1HXCOMM See docs/devel/docs.rst for the format of this file. 2HXCOMM 3HXCOMM Use DEFHEADING() to define headings in both help text and rST. 4HXCOMM Text between SRST and ERST is copied to the rST version and 5HXCOMM discarded from C version. 6HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 7HXCOMM construct option structures, enums and help message for specified 8HXCOMM architectures. 9HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 10 11DEFHEADING(Standard options:) 12 13DEF("help", 0, QEMU_OPTION_h, 14 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 15SRST 16``-h`` 17 Display help and exit 18ERST 19 20DEF("version", 0, QEMU_OPTION_version, 21 "-version display version information and exit\n", QEMU_ARCH_ALL) 22SRST 23``-version`` 24 Display version information and exit 25ERST 26 27DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 28 "-machine [type=]name[,prop[=value][,...]]\n" 29 " selects emulated machine ('-machine help' for list)\n" 30 " property accel=accel1[:accel2[:...]] selects accelerator\n" 31 " supported accelerators are kvm, xen, hvf, nvmm, whpx or tcg (default: tcg)\n" 32 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 33 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 34 " mem-merge=on|off controls memory merge support (default: on)\n" 35 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 36 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 37 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 38 " nvdimm=on|off controls NVDIMM support (default=off)\n" 39 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 40 " hmat=on|off controls ACPI HMAT support (default=off)\n" 41 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 42 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n", 43 QEMU_ARCH_ALL) 44SRST 45``-machine [type=]name[,prop=value[,...]]`` 46 Select the emulated machine by name. Use ``-machine help`` to list 47 available machines. 48 49 For architectures which aim to support live migration compatibility 50 across releases, each release will introduce a new versioned machine 51 type. For example, the 2.8.0 release introduced machine types 52 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 53 54 To allow live migration of guests from QEMU version 2.8.0, to QEMU 55 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 56 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 57 skip multiple intermediate releases when upgrading, new releases of 58 QEMU will support machine types from many previous versions. 59 60 Supported machine properties are: 61 62 ``accel=accels1[:accels2[:...]]`` 63 This is used to enable an accelerator. Depending on the target 64 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. 65 By default, tcg is used. If there is more than one accelerator 66 specified, the next one is used if the previous one fails to 67 initialize. 68 69 ``vmport=on|off|auto`` 70 Enables emulation of VMWare IO port, for vmmouse etc. auto says 71 to select the value based on accel. For accel=xen the default is 72 off otherwise the default is on. 73 74 ``dump-guest-core=on|off`` 75 Include guest memory in a core dump. The default is on. 76 77 ``mem-merge=on|off`` 78 Enables or disables memory merge support. This feature, when 79 supported by the host, de-duplicates identical memory pages 80 among VMs instances (enabled by default). 81 82 ``aes-key-wrap=on|off`` 83 Enables or disables AES key wrapping support on s390-ccw hosts. 84 This feature controls whether AES wrapping keys will be created 85 to allow execution of AES cryptographic functions. The default 86 is on. 87 88 ``dea-key-wrap=on|off`` 89 Enables or disables DEA key wrapping support on s390-ccw hosts. 90 This feature controls whether DEA wrapping keys will be created 91 to allow execution of DEA cryptographic functions. The default 92 is on. 93 94 ``nvdimm=on|off`` 95 Enables or disables NVDIMM support. The default is off. 96 97 ``memory-encryption=`` 98 Memory encryption object to use. The default is none. 99 100 ``hmat=on|off`` 101 Enables or disables ACPI Heterogeneous Memory Attribute Table 102 (HMAT) support. The default is off. 103 104 ``memory-backend='id'`` 105 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 106 Allows to use a memory backend as main RAM. 107 108 For example: 109 :: 110 111 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 112 -machine memory-backend=pc.ram 113 -m 512M 114 115 Migration compatibility note: 116 117 * as backend id one shall use value of 'default-ram-id', advertised by 118 machine type (available via ``query-machines`` QMP command), if migration 119 to/from old QEMU (<5.0) is expected. 120 * for machine types 4.0 and older, user shall 121 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 122 if migration to/from old QEMU (<5.0) is expected. 123 124 For example: 125 :: 126 127 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 128 -machine memory-backend=pc.ram 129 -m 512M 130 131 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 132 Define a CXL Fixed Memory Window (CFMW). 133 134 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 135 136 They are regions of Host Physical Addresses (HPA) on a system which 137 may be interleaved across one or more CXL host bridges. The system 138 software will assign particular devices into these windows and 139 configure the downstream Host-managed Device Memory (HDM) decoders 140 in root ports, switch ports and devices appropriately to meet the 141 interleave requirements before enabling the memory devices. 142 143 ``targets.X=target`` provides the mapping to CXL host bridges 144 which may be identified by the id provided in the -device entry. 145 Multiple entries are needed to specify all the targets when 146 the fixed memory window represents interleaved memory. X is the 147 target index from 0. 148 149 ``size=size`` sets the size of the CFMW. This must be a multiple of 150 256MiB. The region will be aligned to 256MiB but the location is 151 platform and configuration dependent. 152 153 ``interleave-granularity=granularity`` sets the granularity of 154 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 155 4096KiB, 8192KiB and 16384KiB granularities supported. 156 157 Example: 158 159 :: 160 161 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 162ERST 163 164DEF("M", HAS_ARG, QEMU_OPTION_M, 165 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 166 QEMU_ARCH_ALL) 167 168SRST 169``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 170 Define an SGX EPC section. 171ERST 172 173DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 174 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 175SRST 176``-cpu model`` 177 Select CPU model (``-cpu help`` for list and additional feature 178 selection) 179ERST 180 181DEF("accel", HAS_ARG, QEMU_OPTION_accel, 182 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 183 " select accelerator (kvm, xen, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 184 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 185 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 186 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 187 " one-insn-per-tb=on|off (one guest instruction per TCG translation block)\n" 188 " split-wx=on|off (enable TCG split w^x mapping)\n" 189 " tb-size=n (TCG translation block cache size)\n" 190 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 191 " eager-split-size=n (KVM Eager Page Split chunk size, default 0, disabled. ARM only)\n" 192 " notify-vmexit=run|internal-error|disable,notify-window=n (enable notify VM exit and set notify window, x86 only)\n" 193 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 194SRST 195``-accel name[,prop=value[,...]]`` 196 This is used to enable an accelerator. Depending on the target 197 architecture, kvm, xen, hvf, nvmm, whpx or tcg can be available. By 198 default, tcg is used. If there is more than one accelerator 199 specified, the next one is used if the previous one fails to 200 initialize. 201 202 ``igd-passthru=on|off`` 203 When Xen is in use, this option controls whether Intel 204 integrated graphics devices can be passed through to the guest 205 (default=off) 206 207 ``kernel-irqchip=on|off|split`` 208 Controls KVM in-kernel irqchip support. The default is full 209 acceleration of the interrupt controllers. On x86, split irqchip 210 reduces the kernel attack surface, at a performance cost for 211 non-MSI interrupts. Disabling the in-kernel irqchip completely 212 is not recommended except for debugging purposes. 213 214 ``kvm-shadow-mem=size`` 215 Defines the size of the KVM shadow MMU. 216 217 ``one-insn-per-tb=on|off`` 218 Makes the TCG accelerator put only one guest instruction into 219 each translation block. This slows down emulation a lot, but 220 can be useful in some situations, such as when trying to analyse 221 the logs produced by the ``-d`` option. 222 223 ``split-wx=on|off`` 224 Controls the use of split w^x mapping for the TCG code generation 225 buffer. Some operating systems require this to be enabled, and in 226 such a case this will default on. On other operating systems, this 227 will default off, but one may enable this for testing or debugging. 228 229 ``tb-size=n`` 230 Controls the size (in MiB) of the TCG translation block cache. 231 232 ``thread=single|multi`` 233 Controls number of TCG threads. When the TCG is multi-threaded 234 there will be one thread per vCPU therefore taking advantage of 235 additional host cores. The default is to enable multi-threading 236 where both the back-end and front-ends support it and no 237 incompatible TCG features have been enabled (e.g. 238 icount/replay). 239 240 ``dirty-ring-size=n`` 241 When the KVM accelerator is used, it controls the size of the per-vCPU 242 dirty page ring buffer (number of entries for each vCPU). It should 243 be a value that is power of two, and it should be 1024 or bigger (but 244 still less than the maximum value that the kernel supports). 4096 245 could be a good initial value if you have no idea which is the best. 246 Set this value to 0 to disable the feature. By default, this feature 247 is disabled (dirty-ring-size=0). When enabled, KVM will instead 248 record dirty pages in a bitmap. 249 250 ``eager-split-size=n`` 251 KVM implements dirty page logging at the PAGE_SIZE granularity and 252 enabling dirty-logging on a huge-page requires breaking it into 253 PAGE_SIZE pages in the first place. KVM on ARM does this splitting 254 lazily by default. There are performance benefits in doing huge-page 255 split eagerly, especially in situations where TLBI costs associated 256 with break-before-make sequences are considerable and also if guest 257 workloads are read intensive. The size here specifies how many pages 258 to break at a time and needs to be a valid block size which is 259 1GB/2MB/4KB, 32MB/16KB and 512MB/64KB for 4KB/16KB/64KB PAGE_SIZE 260 respectively. Be wary of specifying a higher size as it will have an 261 impact on the memory. By default, this feature is disabled 262 (eager-split-size=0). 263 264 ``notify-vmexit=run|internal-error|disable,notify-window=n`` 265 Enables or disables notify VM exit support on x86 host and specify 266 the corresponding notify window to trigger the VM exit if enabled. 267 ``run`` option enables the feature. It does nothing and continue 268 if the exit happens. ``internal-error`` option enables the feature. 269 It raises a internal error. ``disable`` option doesn't enable the feature. 270 This feature can mitigate the CPU stuck issue due to event windows don't 271 open up for a specified of time (i.e. notify-window). 272 Default: notify-vmexit=run,notify-window=0. 273 274ERST 275 276DEF("smp", HAS_ARG, QEMU_OPTION_smp, 277 "-smp [[cpus=]n][,maxcpus=maxcpus][,drawers=drawers][,books=books][,sockets=sockets]\n" 278 " [,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 279 " set the number of initial CPUs to 'n' [default=1]\n" 280 " maxcpus= maximum number of total CPUs, including\n" 281 " offline CPUs for hotplug, etc\n" 282 " drawers= number of drawers on the machine board\n" 283 " books= number of books in one drawer\n" 284 " sockets= number of sockets in one book\n" 285 " dies= number of dies in one socket\n" 286 " clusters= number of clusters in one die\n" 287 " cores= number of cores in one cluster\n" 288 " threads= number of threads in one core\n" 289 "Note: Different machines may have different subsets of the CPU topology\n" 290 " parameters supported, so the actual meaning of the supported parameters\n" 291 " will vary accordingly. For example, for a machine type that supports a\n" 292 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 293 " sequentially mean as below:\n" 294 " sockets means the number of sockets on the machine board\n" 295 " cores means the number of cores in one socket\n" 296 " threads means the number of threads in one core\n" 297 " For a particular machine type board, an expected CPU topology hierarchy\n" 298 " can be defined through the supported sub-option. Unsupported parameters\n" 299 " can also be provided in addition to the sub-option, but their values\n" 300 " must be set as 1 in the purpose of correct parsing.\n", 301 QEMU_ARCH_ALL) 302SRST 303``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 304 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 305 the machine type board. On boards supporting CPU hotplug, the optional 306 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 307 added at runtime. When both parameters are omitted, the maximum number 308 of CPUs will be calculated from the provided topology members and the 309 initial CPU count will match the maximum number. When only one of them 310 is given then the omitted one will be set to its counterpart's value. 311 Both parameters may be specified, but the maximum number of CPUs must 312 be equal to or greater than the initial CPU count. Product of the 313 CPU topology hierarchy must be equal to the maximum number of CPUs. 314 Both parameters are subject to an upper limit that is determined by 315 the specific machine type chosen. 316 317 To control reporting of CPU topology information, values of the topology 318 parameters can be specified. Machines may only support a subset of the 319 parameters and different machines may have different subsets supported 320 which vary depending on capacity of the corresponding CPU targets. So 321 for a particular machine type board, an expected topology hierarchy can 322 be defined through the supported sub-option. Unsupported parameters can 323 also be provided in addition to the sub-option, but their values must be 324 set as 1 in the purpose of correct parsing. 325 326 Either the initial CPU count, or at least one of the topology parameters 327 must be specified. The specified parameters must be greater than zero, 328 explicit configuration like "cpus=0" is not allowed. Values for any 329 omitted parameters will be computed from those which are given. 330 331 For example, the following sub-option defines a CPU topology hierarchy 332 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 333 core) for a machine that only supports sockets/cores/threads. 334 Some members of the option can be omitted but their values will be 335 automatically computed: 336 337 :: 338 339 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 340 341 The following sub-option defines a CPU topology hierarchy (2 sockets 342 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 343 per core) for PC machines which support sockets/dies/cores/threads. 344 Some members of the option can be omitted but their values will be 345 automatically computed: 346 347 :: 348 349 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 350 351 The following sub-option defines a CPU topology hierarchy (2 sockets 352 totally on the machine, 2 clusters per socket, 2 cores per cluster, 353 2 threads per core) for ARM virt machines which support sockets/clusters 354 /cores/threads. Some members of the option can be omitted but their values 355 will be automatically computed: 356 357 :: 358 359 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 360 361 Historically preference was given to the coarsest topology parameters 362 when computing missing values (ie sockets preferred over cores, which 363 were preferred over threads), however, this behaviour is considered 364 liable to change. Prior to 6.2 the preference was sockets over cores 365 over threads. Since 6.2 the preference is cores over sockets over threads. 366 367 For example, the following option defines a machine board with 2 sockets 368 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 369 370 :: 371 372 -smp 2 373 374 Note: The cluster topology will only be generated in ACPI and exposed 375 to guest if it's explicitly specified in -smp. 376ERST 377 378DEF("numa", HAS_ARG, QEMU_OPTION_numa, 379 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 380 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 381 "-numa dist,src=source,dst=destination,val=distance\n" 382 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 383 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 384 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 385 QEMU_ARCH_ALL) 386SRST 387``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 388 \ 389``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 390 \ 391``-numa dist,src=source,dst=destination,val=distance`` 392 \ 393``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 394 \ 395``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=type[,latency=lat][,bandwidth=bw]`` 396 \ 397``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 398 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 399 distance from a source node to a destination node. Set the ACPI 400 Heterogeneous Memory Attributes for the given nodes. 401 402 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 403 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 404 contiguous range of CPU indexes (or a single VCPU if lastcpu is 405 omitted). A non-contiguous set of VCPUs can be represented by 406 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 407 omitted on all nodes, VCPUs are automatically split between them. 408 409 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 410 NUMA node: 411 412 :: 413 414 -numa node,cpus=0-2,cpus=5 415 416 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 417 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 418 assign CPU objects to a node using topology layout properties of 419 CPU. The set of properties is machine specific, and depends on used 420 machine type/'\ ``smp``\ ' options. It could be queried with 421 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 422 property specifies node to which CPU object will be assigned, it's 423 required for node to be declared with '\ ``node``\ ' option before 424 it's used with '\ ``cpu``\ ' option. 425 426 For example: 427 428 :: 429 430 -M pc \ 431 -smp 1,sockets=2,maxcpus=2 \ 432 -numa node,nodeid=0 -numa node,nodeid=1 \ 433 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 434 435 '\ ``memdev``\ ' option assigns RAM from a given memory backend 436 device to a node. It is recommended to use '\ ``memdev``\ ' option 437 over legacy '\ ``mem``\ ' option. This is because '\ ``memdev``\ ' 438 option provides better performance and more control over the 439 backend's RAM (e.g. '\ ``prealloc``\ ' parameter of 440 '\ ``-memory-backend-ram``\ ' allows memory preallocation). 441 442 For compatibility reasons, legacy '\ ``mem``\ ' option is 443 supported in 5.0 and older machine types. Note that '\ ``mem``\ ' 444 and '\ ``memdev``\ ' are mutually exclusive. If one node uses 445 '\ ``memdev``\ ', the rest nodes have to use '\ ``memdev``\ ' 446 option, and vice versa. 447 448 Users must specify memory for all NUMA nodes by '\ ``memdev``\ ' 449 (or legacy '\ ``mem``\ ' if available). In QEMU 5.2, the support 450 for '\ ``-numa node``\ ' without memory specified was removed. 451 452 '\ ``initiator``\ ' is an additional option that points to an 453 initiator NUMA node that has best performance (the lowest latency or 454 largest bandwidth) to this NUMA node. Note that this option can be 455 set only when the machine property 'hmat' is set to 'on'. 456 457 Following example creates a machine with 2 NUMA nodes, node 0 has 458 CPU. node 1 has only memory, and its initiator is node 0. Note that 459 because node 0 has CPU, by default the initiator of node 0 is itself 460 and must be itself. 461 462 :: 463 464 -machine hmat=on \ 465 -m 2G,slots=2,maxmem=4G \ 466 -object memory-backend-ram,size=1G,id=m0 \ 467 -object memory-backend-ram,size=1G,id=m1 \ 468 -numa node,nodeid=0,memdev=m0 \ 469 -numa node,nodeid=1,memdev=m1,initiator=0 \ 470 -smp 2,sockets=2,maxcpus=2 \ 471 -numa cpu,node-id=0,socket-id=0 \ 472 -numa cpu,node-id=0,socket-id=1 473 474 source and destination are NUMA node IDs. distance is the NUMA 475 distance from source to destination. The distance from a node to 476 itself is always 10. If any pair of nodes is given a distance, then 477 all pairs must be given distances. Although, when distances are only 478 given in one direction for each pair of nodes, then the distances in 479 the opposite directions are assumed to be the same. If, however, an 480 asymmetrical pair of distances is given for even one node pair, then 481 all node pairs must be provided distance values for both directions, 482 even when they are symmetrical. When a node is unreachable from 483 another node, set the pair's distance to 255. 484 485 Note that the -``numa`` option doesn't allocate any of the specified 486 resources, it just assigns existing resources to NUMA nodes. This 487 means that one still has to use the ``-m``, ``-smp`` options to 488 allocate RAM and VCPUs respectively. 489 490 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 491 Information between initiator and target NUMA nodes in ACPI 492 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 493 create memory requests, usually it has one or more processors. 494 Target NUMA node contains addressable memory. 495 496 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 497 the memory hierarchy of the target NUMA node: if hierarchy is 498 'memory', the structure represents the memory performance; if 499 hierarchy is 'first-level\|second-level\|third-level', this 500 structure represents aggregated performance of memory side caches 501 for each domain. type of 'data-type' is type of data represented by 502 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 503 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 504 the target memory; if 'hierarchy' is 505 'first-level\|second-level\|third-level', 'data-type' is 506 'access\|read\|write' hit latency or 'access\|read\|write' hit 507 bandwidth of the target memory side cache. 508 509 lat is latency value in nanoseconds. bw is bandwidth value, the 510 possible value and units are NUM[M\|G\|T], mean that the bandwidth 511 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 512 used suffix). Note that if latency or bandwidth value is 0, means 513 the corresponding latency or bandwidth information is not provided. 514 515 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 516 belongs. size is the size of memory side cache in bytes. level is 517 the cache level described in this structure, note that the cache 518 level 0 should not be used with '\ ``hmat-cache``\ ' option. 519 associativity is the cache associativity, the possible value is 520 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 521 is the write policy. line is the cache Line size in bytes. 522 523 For example, the following options describe 2 NUMA nodes. Node 0 has 524 2 cpus and a ram, node 1 has only a ram. The processors in node 0 525 access memory in node 0 with access-latency 5 nanoseconds, 526 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 527 memory in NUMA node 1 with access-latency 10 nanoseconds, 528 access-bandwidth is 100 MB/s. And for memory side cache information, 529 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 530 policy is write-back, the cache Line size is 8 bytes: 531 532 :: 533 534 -machine hmat=on \ 535 -m 2G \ 536 -object memory-backend-ram,size=1G,id=m0 \ 537 -object memory-backend-ram,size=1G,id=m1 \ 538 -smp 2,sockets=2,maxcpus=2 \ 539 -numa node,nodeid=0,memdev=m0 \ 540 -numa node,nodeid=1,memdev=m1,initiator=0 \ 541 -numa cpu,node-id=0,socket-id=0 \ 542 -numa cpu,node-id=0,socket-id=1 \ 543 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 544 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 545 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 546 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 547 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 548 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 549ERST 550 551DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 552 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 553 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 554SRST 555``-add-fd fd=fd,set=set[,opaque=opaque]`` 556 Add a file descriptor to an fd set. Valid options are: 557 558 ``fd=fd`` 559 This option defines the file descriptor of which a duplicate is 560 added to fd set. The file descriptor cannot be stdin, stdout, or 561 stderr. 562 563 ``set=set`` 564 This option defines the ID of the fd set to add the file 565 descriptor to. 566 567 ``opaque=opaque`` 568 This option defines a free-form string that can be used to 569 describe fd. 570 571 You can open an image using pre-opened file descriptors from an fd 572 set: 573 574 .. parsed-literal:: 575 576 |qemu_system| \\ 577 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 578 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 579 -drive file=/dev/fdset/2,index=0,media=disk 580ERST 581 582DEF("set", HAS_ARG, QEMU_OPTION_set, 583 "-set group.id.arg=value\n" 584 " set <arg> parameter for item <id> of type <group>\n" 585 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 586SRST 587``-set group.id.arg=value`` 588 Set parameter arg for item id of type group 589ERST 590 591DEF("global", HAS_ARG, QEMU_OPTION_global, 592 "-global driver.property=value\n" 593 "-global driver=driver,property=property,value=value\n" 594 " set a global default for a driver property\n", 595 QEMU_ARCH_ALL) 596SRST 597``-global driver.prop=value`` 598 \ 599``-global driver=driver,property=property,value=value`` 600 Set default value of driver's property prop to value, e.g.: 601 602 .. parsed-literal:: 603 604 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 605 606 In particular, you can use this to set driver properties for devices 607 which are created automatically by the machine model. To create a 608 device which is not created automatically and set properties on it, 609 use -``device``. 610 611 -global driver.prop=value is shorthand for -global 612 driver=driver,property=prop,value=value. The longhand syntax works 613 even when driver contains a dot. 614ERST 615 616DEF("boot", HAS_ARG, QEMU_OPTION_boot, 617 "-boot [order=drives][,once=drives][,menu=on|off]\n" 618 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 619 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 620 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 621 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 622 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 623 QEMU_ARCH_ALL) 624SRST 625``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 626 Specify boot order drives as a string of drive letters. Valid drive 627 letters depend on the target architecture. The x86 PC uses: a, b 628 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 629 (Etherboot from network adapter 1-4), hard disk boot is the default. 630 To apply a particular boot order only on the first startup, specify 631 it via ``once``. Note that the ``order`` or ``once`` parameter 632 should not be used together with the ``bootindex`` property of 633 devices, since the firmware implementations normally do not support 634 both at the same time. 635 636 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 637 as firmware/BIOS supports them. The default is non-interactive boot. 638 639 A splash picture could be passed to bios, enabling user to show it 640 as logo, when option splash=sp\_name is given and menu=on, If 641 firmware/BIOS supports them. Currently Seabios for X86 system 642 support it. limitation: The splash file could be a jpeg file or a 643 BMP file in 24 BPP format(true color). The resolution should be 644 supported by the SVGA mode, so the recommended is 320x240, 640x480, 645 800x640. 646 647 A timeout could be passed to bios, guest will pause for rb\_timeout 648 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 649 not reboot, qemu passes '-1' to bios by default. Currently Seabios 650 for X86 system support it. 651 652 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 653 it. This only effects when boot priority is changed by bootindex 654 options. The default is non-strict boot. 655 656 .. parsed-literal:: 657 658 # try to boot from network first, then from hard disk 659 |qemu_system_x86| -boot order=nc 660 # boot from CD-ROM first, switch back to default order after reboot 661 |qemu_system_x86| -boot once=d 662 # boot with a splash picture for 5 seconds. 663 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 664 665 Note: The legacy format '-boot drives' is still supported but its 666 use is discouraged as it may be removed from future versions. 667ERST 668 669DEF("m", HAS_ARG, QEMU_OPTION_m, 670 "-m [size=]megs[,slots=n,maxmem=size]\n" 671 " configure guest RAM\n" 672 " size: initial amount of guest memory\n" 673 " slots: number of hotplug slots (default: none)\n" 674 " maxmem: maximum amount of guest memory (default: none)\n" 675 " Note: Some architectures might enforce a specific granularity\n", 676 QEMU_ARCH_ALL) 677SRST 678``-m [size=]megs[,slots=n,maxmem=size]`` 679 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 680 Optionally, a suffix of "M" or "G" can be used to signify a value in 681 megabytes or gigabytes respectively. Optional pair slots, maxmem 682 could be used to set amount of hotpluggable memory slots and maximum 683 amount of memory. Note that maxmem must be aligned to the page size. 684 685 For example, the following command-line sets the guest startup RAM 686 size to 1GB, creates 3 slots to hotplug additional memory and sets 687 the maximum memory the guest can reach to 4GB: 688 689 .. parsed-literal:: 690 691 |qemu_system| -m 1G,slots=3,maxmem=4G 692 693 If slots and maxmem are not specified, memory hotplug won't be 694 enabled and the guest startup RAM will never increase. 695ERST 696 697DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 698 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 699SRST 700``-mem-path path`` 701 Allocate guest RAM from a temporarily created file in path. 702ERST 703 704DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 705 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 706 QEMU_ARCH_ALL) 707SRST 708``-mem-prealloc`` 709 Preallocate memory when using -mem-path. 710ERST 711 712DEF("k", HAS_ARG, QEMU_OPTION_k, 713 "-k language use keyboard layout (for example 'fr' for French)\n", 714 QEMU_ARCH_ALL) 715SRST 716``-k language`` 717 Use keyboard layout language (for example ``fr`` for French). This 718 option is only needed where it is not easy to get raw PC keycodes 719 (e.g. on Macs, with some X11 servers or with a VNC or curses 720 display). You don't normally need to use it on PC/Linux or 721 PC/Windows hosts. 722 723 The available layouts are: 724 725 :: 726 727 ar de-ch es fo fr-ca hu ja mk no pt-br sv 728 da en-gb et fr fr-ch is lt nl pl ru th 729 de en-us fi fr-be hr it lv nl-be pt sl tr 730 731 The default is ``en-us``. 732ERST 733 734 735DEF("audio", HAS_ARG, QEMU_OPTION_audio, 736 "-audio [driver=]driver[,prop[=value][,...]]\n" 737 " specifies default audio backend when `audiodev` is not\n" 738 " used to create a machine or sound device;" 739 " options are the same as for -audiodev\n" 740 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 741 " specifies the audio backend and device to use;\n" 742 " apart from 'model', options are the same as for -audiodev.\n" 743 " use '-audio model=help' to show possible devices.\n", 744 QEMU_ARCH_ALL) 745SRST 746``-audio [driver=]driver[,model=value][,prop[=value][,...]]`` 747 If the ``model`` option is specified, ``-audio`` is a shortcut 748 for configuring both the guest audio hardware and the host audio 749 backend in one go. The guest hardware model can be set with 750 ``model=modelname``. Use ``model=help`` to list the available 751 device types. 752 753 The following two example do exactly the same, to show how ``-audio`` 754 can be used to shorten the command line length: 755 756 .. parsed-literal:: 757 758 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 759 |qemu_system| -audio pa,model=sb16 760 761 If the ``model`` option is not specified, ``-audio`` is used to 762 configure a default audio backend that will be used whenever the 763 ``audiodev`` property is not set on a device or machine. In 764 particular, ``-audio none`` ensures that no audio is produced even 765 for machines that have embedded sound hardware. 766 767 In both cases, the driver option is the same as with the corresponding 768 ``-audiodev`` option below. Use ``driver=help`` to list the available 769 drivers. 770 771ERST 772 773DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 774 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 775 " specifies the audio backend to use\n" 776 " Use ``-audiodev help`` to list the available drivers\n" 777 " id= identifier of the backend\n" 778 " timer-period= timer period in microseconds\n" 779 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 780 " in|out.fixed-settings= use fixed settings for host audio\n" 781 " in|out.frequency= frequency to use with fixed settings\n" 782 " in|out.channels= number of channels to use with fixed settings\n" 783 " in|out.format= sample format to use with fixed settings\n" 784 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 785 " in|out.voices= number of voices to use\n" 786 " in|out.buffer-length= length of buffer in microseconds\n" 787 "-audiodev none,id=id,[,prop[=value][,...]]\n" 788 " dummy driver that discards all output\n" 789#ifdef CONFIG_AUDIO_ALSA 790 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 791 " in|out.dev= name of the audio device to use\n" 792 " in|out.period-length= length of period in microseconds\n" 793 " in|out.try-poll= attempt to use poll mode\n" 794 " threshold= threshold (in microseconds) when playback starts\n" 795#endif 796#ifdef CONFIG_AUDIO_COREAUDIO 797 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 798 " in|out.buffer-count= number of buffers\n" 799#endif 800#ifdef CONFIG_AUDIO_DSOUND 801 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 802 " latency= add extra latency to playback in microseconds\n" 803#endif 804#ifdef CONFIG_AUDIO_OSS 805 "-audiodev oss,id=id[,prop[=value][,...]]\n" 806 " in|out.dev= path of the audio device to use\n" 807 " in|out.buffer-count= number of buffers\n" 808 " in|out.try-poll= attempt to use poll mode\n" 809 " try-mmap= try using memory mapped access\n" 810 " exclusive= open device in exclusive mode\n" 811 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 812#endif 813#ifdef CONFIG_AUDIO_PA 814 "-audiodev pa,id=id[,prop[=value][,...]]\n" 815 " server= PulseAudio server address\n" 816 " in|out.name= source/sink device name\n" 817 " in|out.latency= desired latency in microseconds\n" 818#endif 819#ifdef CONFIG_AUDIO_PIPEWIRE 820 "-audiodev pipewire,id=id[,prop[=value][,...]]\n" 821 " in|out.name= source/sink device name\n" 822 " in|out.stream-name= name of pipewire stream\n" 823 " in|out.latency= desired latency in microseconds\n" 824#endif 825#ifdef CONFIG_AUDIO_SDL 826 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 827 " in|out.buffer-count= number of buffers\n" 828#endif 829#ifdef CONFIG_AUDIO_SNDIO 830 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 831#endif 832#ifdef CONFIG_SPICE 833 "-audiodev spice,id=id[,prop[=value][,...]]\n" 834#endif 835#ifdef CONFIG_DBUS_DISPLAY 836 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 837#endif 838 "-audiodev wav,id=id[,prop[=value][,...]]\n" 839 " path= path of wav file to record\n", 840 QEMU_ARCH_ALL) 841SRST 842``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 843 Adds a new audio backend driver identified by id. There are global 844 and driver specific properties. Some values can be set differently 845 for input and output, they're marked with ``in|out.``. You can set 846 the input's property with ``in.prop`` and the output's property with 847 ``out.prop``. For example: 848 849 :: 850 851 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 852 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 853 854 NOTE: parameter validation is known to be incomplete, in many cases 855 specifying an invalid option causes QEMU to print an error message 856 and continue emulation without sound. 857 858 Valid global options are: 859 860 ``id=identifier`` 861 Identifies the audio backend. 862 863 ``timer-period=period`` 864 Sets the timer period used by the audio subsystem in 865 microseconds. Default is 10000 (10 ms). 866 867 ``in|out.mixing-engine=on|off`` 868 Use QEMU's mixing engine to mix all streams inside QEMU and 869 convert audio formats when not supported by the backend. When 870 off, fixed-settings must be off too. Note that disabling this 871 option means that the selected backend must support multiple 872 streams and the audio formats used by the virtual cards, 873 otherwise you'll get no sound. It's not recommended to disable 874 this option unless you want to use 5.1 or 7.1 audio, as mixing 875 engine only supports mono and stereo audio. Default is on. 876 877 ``in|out.fixed-settings=on|off`` 878 Use fixed settings for host audio. When off, it will change 879 based on how the guest opens the sound card. In this case you 880 must not specify frequency, channels or format. Default is on. 881 882 ``in|out.frequency=frequency`` 883 Specify the frequency to use when using fixed-settings. Default 884 is 44100Hz. 885 886 ``in|out.channels=channels`` 887 Specify the number of channels to use when using fixed-settings. 888 Default is 2 (stereo). 889 890 ``in|out.format=format`` 891 Specify the sample format to use when using fixed-settings. 892 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 893 ``u32``, ``f32``. Default is ``s16``. 894 895 ``in|out.voices=voices`` 896 Specify the number of voices to use. Default is 1. 897 898 ``in|out.buffer-length=usecs`` 899 Sets the size of the buffer in microseconds. 900 901``-audiodev none,id=id[,prop[=value][,...]]`` 902 Creates a dummy backend that discards all outputs. This backend has 903 no backend specific properties. 904 905``-audiodev alsa,id=id[,prop[=value][,...]]`` 906 Creates backend using the ALSA. This backend is only available on 907 Linux. 908 909 ALSA specific options are: 910 911 ``in|out.dev=device`` 912 Specify the ALSA device to use for input and/or output. Default 913 is ``default``. 914 915 ``in|out.period-length=usecs`` 916 Sets the period length in microseconds. 917 918 ``in|out.try-poll=on|off`` 919 Attempt to use poll mode with the device. Default is on. 920 921 ``threshold=threshold`` 922 Threshold (in microseconds) when playback starts. Default is 0. 923 924``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 925 Creates a backend using Apple's Core Audio. This backend is only 926 available on Mac OS and only supports playback. 927 928 Core Audio specific options are: 929 930 ``in|out.buffer-count=count`` 931 Sets the count of the buffers. 932 933``-audiodev dsound,id=id[,prop[=value][,...]]`` 934 Creates a backend using Microsoft's DirectSound. This backend is 935 only available on Windows and only supports playback. 936 937 DirectSound specific options are: 938 939 ``latency=usecs`` 940 Add extra usecs microseconds latency to playback. Default is 941 10000 (10 ms). 942 943``-audiodev oss,id=id[,prop[=value][,...]]`` 944 Creates a backend using OSS. This backend is available on most 945 Unix-like systems. 946 947 OSS specific options are: 948 949 ``in|out.dev=device`` 950 Specify the file name of the OSS device to use. Default is 951 ``/dev/dsp``. 952 953 ``in|out.buffer-count=count`` 954 Sets the count of the buffers. 955 956 ``in|out.try-poll=on|of`` 957 Attempt to use poll mode with the device. Default is on. 958 959 ``try-mmap=on|off`` 960 Try using memory mapped device access. Default is off. 961 962 ``exclusive=on|off`` 963 Open the device in exclusive mode (vmix won't work in this 964 case). Default is off. 965 966 ``dsp-policy=policy`` 967 Sets the timing policy (between 0 and 10, where smaller number 968 means smaller latency but higher CPU usage). Use -1 to use 969 buffer sizes specified by ``buffer`` and ``buffer-count``. This 970 option is ignored if you do not have OSS 4. Default is 5. 971 972``-audiodev pa,id=id[,prop[=value][,...]]`` 973 Creates a backend using PulseAudio. This backend is available on 974 most systems. 975 976 PulseAudio specific options are: 977 978 ``server=server`` 979 Sets the PulseAudio server to connect to. 980 981 ``in|out.name=sink`` 982 Use the specified source/sink for recording/playback. 983 984 ``in|out.latency=usecs`` 985 Desired latency in microseconds. The PulseAudio server will try 986 to honor this value but actual latencies may be lower or higher. 987 988``-audiodev pipewire,id=id[,prop[=value][,...]]`` 989 Creates a backend using PipeWire. This backend is available on 990 most systems. 991 992 PipeWire specific options are: 993 994 ``in|out.latency=usecs`` 995 Desired latency in microseconds. 996 997 ``in|out.name=sink`` 998 Use the specified source/sink for recording/playback. 999 1000 ``in|out.stream-name`` 1001 Specify the name of pipewire stream. 1002 1003``-audiodev sdl,id=id[,prop[=value][,...]]`` 1004 Creates a backend using SDL. This backend is available on most 1005 systems, but you should use your platform's native backend if 1006 possible. 1007 1008 SDL specific options are: 1009 1010 ``in|out.buffer-count=count`` 1011 Sets the count of the buffers. 1012 1013``-audiodev sndio,id=id[,prop[=value][,...]]`` 1014 Creates a backend using SNDIO. This backend is available on 1015 OpenBSD and most other Unix-like systems. 1016 1017 Sndio specific options are: 1018 1019 ``in|out.dev=device`` 1020 Specify the sndio device to use for input and/or output. Default 1021 is ``default``. 1022 1023 ``in|out.latency=usecs`` 1024 Sets the desired period length in microseconds. 1025 1026``-audiodev spice,id=id[,prop[=value][,...]]`` 1027 Creates a backend that sends audio through SPICE. This backend 1028 requires ``-spice`` and automatically selected in that case, so 1029 usually you can ignore this option. This backend has no backend 1030 specific properties. 1031 1032``-audiodev wav,id=id[,prop[=value][,...]]`` 1033 Creates a backend that writes audio to a WAV file. 1034 1035 Backend specific options are: 1036 1037 ``path=path`` 1038 Write recorded audio into the specified file. Default is 1039 ``qemu.wav``. 1040ERST 1041 1042DEF("device", HAS_ARG, QEMU_OPTION_device, 1043 "-device driver[,prop[=value][,...]]\n" 1044 " add device (based on driver)\n" 1045 " prop=value,... sets driver properties\n" 1046 " use '-device help' to print all possible drivers\n" 1047 " use '-device driver,help' to print all possible properties\n", 1048 QEMU_ARCH_ALL) 1049SRST 1050``-device driver[,prop[=value][,...]]`` 1051 Add device driver. prop=value sets driver properties. Valid 1052 properties depend on the driver. To get help on possible drivers and 1053 properties, use ``-device help`` and ``-device driver,help``. 1054 1055 Some drivers are: 1056 1057``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 1058 Add an IPMI BMC. This is a simulation of a hardware management 1059 interface processor that normally sits on a system. It provides a 1060 watchdog and the ability to reset and power control the system. You 1061 need to connect this to an IPMI interface to make it useful 1062 1063 The IPMI slave address to use for the BMC. The default is 0x20. This 1064 address is the BMC's address on the I2C network of management 1065 controllers. If you don't know what this means, it is safe to ignore 1066 it. 1067 1068 ``id=id`` 1069 The BMC id for interfaces to use this device. 1070 1071 ``slave_addr=val`` 1072 Define slave address to use for the BMC. The default is 0x20. 1073 1074 ``sdrfile=file`` 1075 file containing raw Sensor Data Records (SDR) data. The default 1076 is none. 1077 1078 ``fruareasize=val`` 1079 size of a Field Replaceable Unit (FRU) area. The default is 1080 1024. 1081 1082 ``frudatafile=file`` 1083 file containing raw Field Replaceable Unit (FRU) inventory data. 1084 The default is none. 1085 1086 ``guid=uuid`` 1087 value for the GUID for the BMC, in standard UUID format. If this 1088 is set, get "Get GUID" command to the BMC will return it. 1089 Otherwise "Get GUID" will return an error. 1090 1091``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1092 Add a connection to an external IPMI BMC simulator. Instead of 1093 locally emulating the BMC like the above item, instead connect to an 1094 external entity that provides the IPMI services. 1095 1096 A connection is made to an external BMC simulator. If you do this, 1097 it is strongly recommended that you use the "reconnect=" chardev 1098 option to reconnect to the simulator if the connection is lost. Note 1099 that if this is not used carefully, it can be a security issue, as 1100 the interface has the ability to send resets, NMIs, and power off 1101 the VM. It's best if QEMU makes a connection to an external 1102 simulator running on a secure port on localhost, so neither the 1103 simulator nor QEMU is exposed to any outside network. 1104 1105 See the "lanserv/README.vm" file in the OpenIPMI library for more 1106 details on the external interface. 1107 1108``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1109 Add a KCS IPMI interface on the ISA bus. This also adds a 1110 corresponding ACPI and SMBIOS entries, if appropriate. 1111 1112 ``bmc=id`` 1113 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1114 above. 1115 1116 ``ioport=val`` 1117 Define the I/O address of the interface. The default is 0xca0 1118 for KCS. 1119 1120 ``irq=val`` 1121 Define the interrupt to use. The default is 5. To disable 1122 interrupts, set this to 0. 1123 1124``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1125 Like the KCS interface, but defines a BT interface. The default port 1126 is 0xe4 and the default interrupt is 5. 1127 1128``-device pci-ipmi-kcs,bmc=id`` 1129 Add a KCS IPMI interface on the PCI bus. 1130 1131 ``bmc=id`` 1132 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1133 1134``-device pci-ipmi-bt,bmc=id`` 1135 Like the KCS interface, but defines a BT interface on the PCI bus. 1136 1137``-device intel-iommu[,option=...]`` 1138 This is only supported by ``-machine q35``, which will enable Intel VT-d 1139 emulation within the guest. It supports below options: 1140 1141 ``intremap=on|off`` (default: auto) 1142 This enables interrupt remapping feature. It's required to enable 1143 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1144 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1145 The default value is "auto", which will be decided by the mode of 1146 kernel-irqchip. 1147 1148 ``caching-mode=on|off`` (default: off) 1149 This enables caching mode for the VT-d emulated device. When 1150 caching-mode is enabled, each guest DMA buffer mapping will generate an 1151 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1152 a synchronous way. It is required for ``-device vfio-pci`` to work 1153 with the VT-d device, because host assigned devices requires to setup 1154 the DMA mapping on the host before guest DMA starts. 1155 1156 ``device-iotlb=on|off`` (default: off) 1157 This enables device-iotlb capability for the emulated VT-d device. So 1158 far virtio/vhost should be the only real user for this parameter, 1159 paired with ats=on configured for the device. 1160 1161 ``aw-bits=39|48`` (default: 39) 1162 This decides the address width of IOVA address space. The address 1163 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1164 4-level IOMMU page tables. 1165 1166 Please also refer to the wiki page for general scenarios of VT-d 1167 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1168 1169ERST 1170 1171DEF("name", HAS_ARG, QEMU_OPTION_name, 1172 "-name string1[,process=string2][,debug-threads=on|off]\n" 1173 " set the name of the guest\n" 1174 " string1 sets the window title and string2 the process name\n" 1175 " When debug-threads is enabled, individual threads are given a separate name\n" 1176 " NOTE: The thread names are for debugging and not a stable API.\n", 1177 QEMU_ARCH_ALL) 1178SRST 1179``-name name`` 1180 Sets the name of the guest. This name will be displayed in the SDL 1181 window caption. The name will also be used for the VNC server. Also 1182 optionally set the top visible process name in Linux. Naming of 1183 individual threads can also be enabled on Linux to aid debugging. 1184ERST 1185 1186DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1187 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1188 " specify machine UUID\n", QEMU_ARCH_ALL) 1189SRST 1190``-uuid uuid`` 1191 Set system UUID. 1192ERST 1193 1194DEFHEADING() 1195 1196DEFHEADING(Block device options:) 1197 1198SRST 1199The QEMU block device handling options have a long history and 1200have gone through several iterations as the feature set and complexity 1201of the block layer have grown. Many online guides to QEMU often 1202reference older and deprecated options, which can lead to confusion. 1203 1204The most explicit way to describe disks is to use a combination of 1205``-device`` to specify the hardware device and ``-blockdev`` to 1206describe the backend. The device defines what the guest sees and the 1207backend describes how QEMU handles the data. It is the only guaranteed 1208stable interface for describing block devices and as such is 1209recommended for management tools and scripting. 1210 1211The ``-drive`` option combines the device and backend into a single 1212command line option which is a more human friendly. There is however no 1213interface stability guarantee although some older board models still 1214need updating to work with the modern blockdev forms. 1215 1216Older options like ``-hda`` are essentially macros which expand into 1217``-drive`` options for various drive interfaces. The original forms 1218bake in a lot of assumptions from the days when QEMU was emulating a 1219legacy PC, they are not recommended for modern configurations. 1220 1221ERST 1222 1223DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1224 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1225DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1226SRST 1227``-fda file`` 1228 \ 1229``-fdb file`` 1230 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1231 the System Emulation Users Guide). 1232ERST 1233 1234DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1235 "-hda/-hdb file use 'file' as hard disk 0/1 image\n", QEMU_ARCH_ALL) 1236DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1237DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1238 "-hdc/-hdd file use 'file' as hard disk 2/3 image\n", QEMU_ARCH_ALL) 1239DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1240SRST 1241``-hda file`` 1242 \ 1243``-hdb file`` 1244 \ 1245``-hdc file`` 1246 \ 1247``-hdd file`` 1248 Use file as hard disk 0, 1, 2 or 3 image on the default bus of the 1249 emulated machine (this is for example the IDE bus on most x86 machines, 1250 but it can also be SCSI, virtio or something else on other target 1251 architectures). See also the :ref:`disk images` chapter in the System 1252 Emulation Users Guide. 1253ERST 1254 1255DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1256 "-cdrom file use 'file' as CD-ROM image\n", 1257 QEMU_ARCH_ALL) 1258SRST 1259``-cdrom file`` 1260 Use file as CD-ROM image on the default bus of the emulated machine 1261 (which is IDE1 master on x86, so you cannot use ``-hdc`` and ``-cdrom`` 1262 at the same time there). On systems that support it, you can use the 1263 host CD-ROM by using ``/dev/cdrom`` as filename. 1264ERST 1265 1266DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1267 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1268 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1269 " [,read-only=on|off][,auto-read-only=on|off]\n" 1270 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1271 " [,driver specific parameters...]\n" 1272 " configure a block backend\n", QEMU_ARCH_ALL) 1273SRST 1274``-blockdev option[,option[,option[,...]]]`` 1275 Define a new block driver node. Some of the options apply to all 1276 block drivers, other options are only accepted for a specific block 1277 driver. See below for a list of generic options and options for the 1278 most common block drivers. 1279 1280 Options that expect a reference to another node (e.g. ``file``) can 1281 be given in two ways. Either you specify the node name of an already 1282 existing node (file=node-name), or you define a new node inline, 1283 adding options for the referenced node after a dot 1284 (file.filename=path,file.aio=native). 1285 1286 A block driver node created with ``-blockdev`` can be used for a 1287 guest device by specifying its node name for the ``drive`` property 1288 in a ``-device`` argument that defines a block device. 1289 1290 ``Valid options for any block driver node:`` 1291 ``driver`` 1292 Specifies the block driver to use for the given node. 1293 1294 ``node-name`` 1295 This defines the name of the block driver node by which it 1296 will be referenced later. The name must be unique, i.e. it 1297 must not match the name of a different block driver node, or 1298 (if you use ``-drive`` as well) the ID of a drive. 1299 1300 If no node name is specified, it is automatically generated. 1301 The generated node name is not intended to be predictable 1302 and changes between QEMU invocations. For the top level, an 1303 explicit node name must be specified. 1304 1305 ``read-only`` 1306 Open the node read-only. Guest write attempts will fail. 1307 1308 Note that some block drivers support only read-only access, 1309 either generally or in certain configurations. In this case, 1310 the default value ``read-only=off`` does not work and the 1311 option must be specified explicitly. 1312 1313 ``auto-read-only`` 1314 If ``auto-read-only=on`` is set, QEMU may fall back to 1315 read-only usage even when ``read-only=off`` is requested, or 1316 even switch between modes as needed, e.g. depending on 1317 whether the image file is writable or whether a writing user 1318 is attached to the node. 1319 1320 ``force-share`` 1321 Override the image locking system of QEMU by forcing the 1322 node to utilize weaker shared access for permissions where 1323 it would normally request exclusive access. When there is 1324 the potential for multiple instances to have the same file 1325 open (whether this invocation of QEMU is the first or the 1326 second instance), both instances must permit shared access 1327 for the second instance to succeed at opening the file. 1328 1329 Enabling ``force-share=on`` requires ``read-only=on``. 1330 1331 ``cache.direct`` 1332 The host page cache can be avoided with ``cache.direct=on``. 1333 This will attempt to do disk IO directly to the guest's 1334 memory. QEMU may still perform an internal copy of the data. 1335 1336 ``cache.no-flush`` 1337 In case you don't care about data integrity over host 1338 failures, you can use ``cache.no-flush=on``. This option 1339 tells QEMU that it never needs to write any data to the disk 1340 but can instead keep things in cache. If anything goes 1341 wrong, like your host losing power, the disk storage getting 1342 disconnected accidentally, etc. your image will most 1343 probably be rendered unusable. 1344 1345 ``discard=discard`` 1346 discard is one of "ignore" (or "off") or "unmap" (or "on") 1347 and controls whether ``discard`` (also known as ``trim`` or 1348 ``unmap``) requests are ignored or passed to the filesystem. 1349 Some machine types may not support discard requests. 1350 1351 ``detect-zeroes=detect-zeroes`` 1352 detect-zeroes is "off", "on" or "unmap" and enables the 1353 automatic conversion of plain zero writes by the OS to 1354 driver specific optimized zero write commands. You may even 1355 choose "unmap" if discard is set to "unmap" to allow a zero 1356 write to be converted to an ``unmap`` operation. 1357 1358 ``Driver-specific options for file`` 1359 This is the protocol-level block driver for accessing regular 1360 files. 1361 1362 ``filename`` 1363 The path to the image file in the local filesystem 1364 1365 ``aio`` 1366 Specifies the AIO backend (threads/native/io_uring, 1367 default: threads) 1368 1369 ``locking`` 1370 Specifies whether the image file is protected with Linux OFD 1371 / POSIX locks. The default is to use the Linux Open File 1372 Descriptor API if available, otherwise no lock is applied. 1373 (auto/on/off, default: auto) 1374 1375 Example: 1376 1377 :: 1378 1379 -blockdev driver=file,node-name=disk,filename=disk.img 1380 1381 ``Driver-specific options for raw`` 1382 This is the image format block driver for raw images. It is 1383 usually stacked on top of a protocol level block driver such as 1384 ``file``. 1385 1386 ``file`` 1387 Reference to or definition of the data source block driver 1388 node (e.g. a ``file`` driver node) 1389 1390 Example 1: 1391 1392 :: 1393 1394 -blockdev driver=file,node-name=disk_file,filename=disk.img 1395 -blockdev driver=raw,node-name=disk,file=disk_file 1396 1397 Example 2: 1398 1399 :: 1400 1401 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1402 1403 ``Driver-specific options for qcow2`` 1404 This is the image format block driver for qcow2 images. It is 1405 usually stacked on top of a protocol level block driver such as 1406 ``file``. 1407 1408 ``file`` 1409 Reference to or definition of the data source block driver 1410 node (e.g. a ``file`` driver node) 1411 1412 ``backing`` 1413 Reference to or definition of the backing file block device 1414 (default is taken from the image file). It is allowed to 1415 pass ``null`` here in order to disable the default backing 1416 file. 1417 1418 ``lazy-refcounts`` 1419 Whether to enable the lazy refcounts feature (on/off; 1420 default is taken from the image file) 1421 1422 ``cache-size`` 1423 The maximum total size of the L2 table and refcount block 1424 caches in bytes (default: the sum of l2-cache-size and 1425 refcount-cache-size) 1426 1427 ``l2-cache-size`` 1428 The maximum size of the L2 table cache in bytes (default: if 1429 cache-size is not specified - 32M on Linux platforms, and 8M 1430 on non-Linux platforms; otherwise, as large as possible 1431 within the cache-size, while permitting the requested or the 1432 minimal refcount cache size) 1433 1434 ``refcount-cache-size`` 1435 The maximum size of the refcount block cache in bytes 1436 (default: 4 times the cluster size; or if cache-size is 1437 specified, the part of it which is not used for the L2 1438 cache) 1439 1440 ``cache-clean-interval`` 1441 Clean unused entries in the L2 and refcount caches. The 1442 interval is in seconds. The default value is 600 on 1443 supporting platforms, and 0 on other platforms. Setting it 1444 to 0 disables this feature. 1445 1446 ``pass-discard-request`` 1447 Whether discard requests to the qcow2 device should be 1448 forwarded to the data source (on/off; default: on if 1449 discard=unmap is specified, off otherwise) 1450 1451 ``pass-discard-snapshot`` 1452 Whether discard requests for the data source should be 1453 issued when a snapshot operation (e.g. deleting a snapshot) 1454 frees clusters in the qcow2 file (on/off; default: on) 1455 1456 ``pass-discard-other`` 1457 Whether discard requests for the data source should be 1458 issued on other occasions where a cluster gets freed 1459 (on/off; default: off) 1460 1461 ``discard-no-unref`` 1462 When enabled, data clusters will remain preallocated when they are 1463 no longer used, e.g. because they are discarded or converted to 1464 zero clusters. As usual, whether the old data is discarded or kept 1465 on the protocol level (i.e. in the image file) depends on the 1466 setting of the pass-discard-request option. Keeping the clusters 1467 preallocated prevents qcow2 fragmentation that would otherwise be 1468 caused by freeing and re-allocating them later. Besides potential 1469 performance degradation, such fragmentation can lead to increased 1470 allocation of clusters past the end of the image file, 1471 resulting in image files whose file length can grow much larger 1472 than their guest disk size would suggest. 1473 If image file length is of concern (e.g. when storing qcow2 1474 images directly on block devices), you should consider enabling 1475 this option. 1476 1477 ``overlap-check`` 1478 Which overlap checks to perform for writes to the image 1479 (none/constant/cached/all; default: cached). For details or 1480 finer granularity control refer to the QAPI documentation of 1481 ``blockdev-add``. 1482 1483 Example 1: 1484 1485 :: 1486 1487 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1488 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1489 1490 Example 2: 1491 1492 :: 1493 1494 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1495 1496 ``Driver-specific options for other drivers`` 1497 Please refer to the QAPI documentation of the ``blockdev-add`` 1498 QMP command. 1499ERST 1500 1501DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1502 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1503 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1504 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1505 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1506 " [,aio=threads|native|io_uring]\n" 1507 " [,readonly=on|off][,copy-on-read=on|off]\n" 1508 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1509 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1510 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1511 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1512 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1513 " [[,iops_size=is]]\n" 1514 " [[,group=g]]\n" 1515 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1516SRST 1517``-drive option[,option[,option[,...]]]`` 1518 Define a new drive. This includes creating a block driver node (the 1519 backend) as well as a guest device, and is mostly a shortcut for 1520 defining the corresponding ``-blockdev`` and ``-device`` options. 1521 1522 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1523 In addition, it knows the following options: 1524 1525 ``file=file`` 1526 This option defines which disk image (see the :ref:`disk images` 1527 chapter in the System Emulation Users Guide) to use with this drive. 1528 If the filename contains comma, you must double it (for instance, 1529 "file=my,,file" to use file "my,file"). 1530 1531 Special files such as iSCSI devices can be specified using 1532 protocol specific URLs. See the section for "Device URL Syntax" 1533 for more information. 1534 1535 ``if=interface`` 1536 This option defines on which type on interface the drive is 1537 connected. Available types are: ide, scsi, sd, mtd, floppy, 1538 pflash, virtio, none. 1539 1540 ``bus=bus,unit=unit`` 1541 These options define where is connected the drive by defining 1542 the bus number and the unit id. 1543 1544 ``index=index`` 1545 This option defines where the drive is connected by using an 1546 index in the list of available connectors of a given interface 1547 type. 1548 1549 ``media=media`` 1550 This option defines the type of the media: disk or cdrom. 1551 1552 ``snapshot=snapshot`` 1553 snapshot is "on" or "off" and controls snapshot mode for the 1554 given drive (see ``-snapshot``). 1555 1556 ``cache=cache`` 1557 cache is "none", "writeback", "unsafe", "directsync" or 1558 "writethrough" and controls how the host cache is used to access 1559 block data. This is a shortcut that sets the ``cache.direct`` 1560 and ``cache.no-flush`` options (as in ``-blockdev``), and 1561 additionally ``cache.writeback``, which provides a default for 1562 the ``write-cache`` option of block guest devices (as in 1563 ``-device``). The modes correspond to the following settings: 1564 1565 ============= =============== ============ ============== 1566 \ cache.writeback cache.direct cache.no-flush 1567 ============= =============== ============ ============== 1568 writeback on off off 1569 none on on off 1570 writethrough off off off 1571 directsync off on off 1572 unsafe on off on 1573 ============= =============== ============ ============== 1574 1575 The default mode is ``cache=writeback``. 1576 1577 ``aio=aio`` 1578 aio is "threads", "native", or "io_uring" and selects between pthread 1579 based disk I/O, native Linux AIO, or Linux io_uring API. 1580 1581 ``format=format`` 1582 Specify which disk format will be used rather than detecting the 1583 format. Can be used to specify format=raw to avoid interpreting 1584 an untrusted format header. 1585 1586 ``werror=action,rerror=action`` 1587 Specify which action to take on write and read errors. Valid 1588 actions are: "ignore" (ignore the error and try to continue), 1589 "stop" (pause QEMU), "report" (report the error to the guest), 1590 "enospc" (pause QEMU only if the host disk is full; report the 1591 error to the guest otherwise). The default setting is 1592 ``werror=enospc`` and ``rerror=report``. 1593 1594 ``copy-on-read=copy-on-read`` 1595 copy-on-read is "on" or "off" and enables whether to copy read 1596 backing file sectors into the image file. 1597 1598 ``bps=b,bps_rd=r,bps_wr=w`` 1599 Specify bandwidth throttling limits in bytes per second, either 1600 for all request types or for reads or writes only. Small values 1601 can lead to timeouts or hangs inside the guest. A safe minimum 1602 for disks is 2 MB/s. 1603 1604 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1605 Specify bursts in bytes per second, either for all request types 1606 or for reads or writes only. Bursts allow the guest I/O to spike 1607 above the limit temporarily. 1608 1609 ``iops=i,iops_rd=r,iops_wr=w`` 1610 Specify request rate limits in requests per second, either for 1611 all request types or for reads or writes only. 1612 1613 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1614 Specify bursts in requests per second, either for all request 1615 types or for reads or writes only. Bursts allow the guest I/O to 1616 spike above the limit temporarily. 1617 1618 ``iops_size=is`` 1619 Let every is bytes of a request count as a new request for iops 1620 throttling purposes. Use this option to prevent guests from 1621 circumventing iops limits by sending fewer but larger requests. 1622 1623 ``group=g`` 1624 Join a throttling quota group with given name g. All drives that 1625 are members of the same group are accounted for together. Use 1626 this option to prevent guests from circumventing throttling 1627 limits by using many small disks instead of a single larger 1628 disk. 1629 1630 By default, the ``cache.writeback=on`` mode is used. It will report 1631 data writes as completed as soon as the data is present in the host 1632 page cache. This is safe as long as your guest OS makes sure to 1633 correctly flush disk caches where needed. If your guest OS does not 1634 handle volatile disk write caches correctly and your host crashes or 1635 loses power, then the guest may experience data corruption. 1636 1637 For such guests, you should consider using ``cache.writeback=off``. 1638 This means that the host page cache will be used to read and write 1639 data, but write notification will be sent to the guest only after 1640 QEMU has made sure to flush each write to the disk. Be aware that 1641 this has a major impact on performance. 1642 1643 When using the ``-snapshot`` option, unsafe caching is always used. 1644 1645 Copy-on-read avoids accessing the same backing file sectors 1646 repeatedly and is useful when the backing file is over a slow 1647 network. By default copy-on-read is off. 1648 1649 Instead of ``-cdrom`` you can use: 1650 1651 .. parsed-literal:: 1652 1653 |qemu_system| -drive file=file,index=2,media=cdrom 1654 1655 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1656 1657 .. parsed-literal:: 1658 1659 |qemu_system| -drive file=file,index=0,media=disk 1660 |qemu_system| -drive file=file,index=1,media=disk 1661 |qemu_system| -drive file=file,index=2,media=disk 1662 |qemu_system| -drive file=file,index=3,media=disk 1663 1664 You can open an image using pre-opened file descriptors from an fd 1665 set: 1666 1667 .. parsed-literal:: 1668 1669 |qemu_system| \\ 1670 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1671 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1672 -drive file=/dev/fdset/2,index=0,media=disk 1673 1674 You can connect a CDROM to the slave of ide0: 1675 1676 .. parsed-literal:: 1677 1678 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1679 1680 If you don't specify the "file=" argument, you define an empty 1681 drive: 1682 1683 .. parsed-literal:: 1684 1685 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1686 1687 Instead of ``-fda``, ``-fdb``, you can use: 1688 1689 .. parsed-literal:: 1690 1691 |qemu_system_x86| -drive file=file,index=0,if=floppy 1692 |qemu_system_x86| -drive file=file,index=1,if=floppy 1693 1694 By default, interface is "ide" and index is automatically 1695 incremented: 1696 1697 .. parsed-literal:: 1698 1699 |qemu_system_x86| -drive file=a -drive file=b 1700 1701 is interpreted like: 1702 1703 .. parsed-literal:: 1704 1705 |qemu_system_x86| -hda a -hdb b 1706ERST 1707 1708DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1709 "-mtdblock file use 'file' as on-board Flash memory image\n", 1710 QEMU_ARCH_ALL) 1711SRST 1712``-mtdblock file`` 1713 Use file as on-board Flash memory image. 1714ERST 1715 1716DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1717 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1718SRST 1719``-sd file`` 1720 Use file as SecureDigital card image. 1721ERST 1722 1723DEF("snapshot", 0, QEMU_OPTION_snapshot, 1724 "-snapshot write to temporary files instead of disk image files\n", 1725 QEMU_ARCH_ALL) 1726SRST 1727``-snapshot`` 1728 Write to temporary files instead of disk image files. In this case, 1729 the raw disk image you use is not written back. You can however 1730 force the write back by pressing C-a s (see the :ref:`disk images` 1731 chapter in the System Emulation Users Guide). 1732 1733 .. warning:: 1734 snapshot is incompatible with ``-blockdev`` (instead use qemu-img 1735 to manually create snapshot images to attach to your blockdev). 1736 If you have mixed ``-blockdev`` and ``-drive`` declarations you 1737 can use the 'snapshot' property on your drive declarations 1738 instead of this global option. 1739 1740ERST 1741 1742DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1743 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1744 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1745 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1746 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1747 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1748 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1749 " [[,throttling.iops-size=is]]\n" 1750 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1751 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1752 "-fsdev synth,id=id\n", 1753 QEMU_ARCH_ALL) 1754 1755SRST 1756``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1757 \ 1758``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1759 \ 1760``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1761 \ 1762``-fsdev synth,id=id[,readonly=on]`` 1763 Define a new file system device. Valid options are: 1764 1765 ``local`` 1766 Accesses to the filesystem are done by QEMU. 1767 1768 ``proxy`` 1769 Accesses to the filesystem are done by virtfs-proxy-helper(1). This 1770 option is deprecated (since QEMU 8.1) and will be removed in a future 1771 version of QEMU. Use ``local`` instead. 1772 1773 ``synth`` 1774 Synthetic filesystem, only used by QTests. 1775 1776 ``id=id`` 1777 Specifies identifier for this device. 1778 1779 ``path=path`` 1780 Specifies the export path for the file system device. Files 1781 under this path will be available to the 9p client on the guest. 1782 1783 ``security_model=security_model`` 1784 Specifies the security model to be used for this export path. 1785 Supported security models are "passthrough", "mapped-xattr", 1786 "mapped-file" and "none". In "passthrough" security model, files 1787 are stored using the same credentials as they are created on the 1788 guest. This requires QEMU to run as root. In "mapped-xattr" 1789 security model, some of the file attributes like uid, gid, mode 1790 bits and link target are stored as file attributes. For 1791 "mapped-file" these attributes are stored in the hidden 1792 .virtfs\_metadata directory. Directories exported by this 1793 security model cannot interact with other unix tools. "none" 1794 security model is same as passthrough except the sever won't 1795 report failures if it fails to set file attributes like 1796 ownership. Security model is mandatory only for local fsdriver. 1797 Other fsdrivers (like proxy) don't take security model as a 1798 parameter. 1799 1800 ``writeout=writeout`` 1801 This is an optional argument. The only supported value is 1802 "immediate". This means that host page cache will be used to 1803 read and write data but write notification will be sent to the 1804 guest only when the data has been reported as written by the 1805 storage subsystem. 1806 1807 ``readonly=on`` 1808 Enables exporting 9p share as a readonly mount for guests. By 1809 default read-write access is given. 1810 1811 ``socket=socket`` 1812 Enables proxy filesystem driver to use passed socket file for 1813 communicating with virtfs-proxy-helper(1). 1814 1815 ``sock_fd=sock_fd`` 1816 Enables proxy filesystem driver to use passed socket descriptor 1817 for communicating with virtfs-proxy-helper(1). Usually a helper 1818 like libvirt will create socketpair and pass one of the fds as 1819 sock\_fd. 1820 1821 ``fmode=fmode`` 1822 Specifies the default mode for newly created files on the host. 1823 Works only with security models "mapped-xattr" and 1824 "mapped-file". 1825 1826 ``dmode=dmode`` 1827 Specifies the default mode for newly created directories on the 1828 host. Works only with security models "mapped-xattr" and 1829 "mapped-file". 1830 1831 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1832 Specify bandwidth throttling limits in bytes per second, either 1833 for all request types or for reads or writes only. 1834 1835 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1836 Specify bursts in bytes per second, either for all request types 1837 or for reads or writes only. Bursts allow the guest I/O to spike 1838 above the limit temporarily. 1839 1840 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1841 Specify request rate limits in requests per second, either for 1842 all request types or for reads or writes only. 1843 1844 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1845 Specify bursts in requests per second, either for all request 1846 types or for reads or writes only. Bursts allow the guest I/O to 1847 spike above the limit temporarily. 1848 1849 ``throttling.iops-size=is`` 1850 Let every is bytes of a request count as a new request for iops 1851 throttling purposes. 1852 1853 -fsdev option is used along with -device driver "virtio-9p-...". 1854 1855``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1856 Options for virtio-9p-... driver are: 1857 1858 ``type`` 1859 Specifies the variant to be used. Supported values are "pci", 1860 "ccw" or "device", depending on the machine type. 1861 1862 ``fsdev=id`` 1863 Specifies the id value specified along with -fsdev option. 1864 1865 ``mount_tag=mount_tag`` 1866 Specifies the tag name to be used by the guest to mount this 1867 export point. 1868ERST 1869 1870DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1871 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1872 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1873 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1874 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1875 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1876 QEMU_ARCH_ALL) 1877 1878SRST 1879``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1880 \ 1881``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1882 \ 1883``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1884 \ 1885``-virtfs synth,mount_tag=mount_tag`` 1886 Define a new virtual filesystem device and expose it to the guest using 1887 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1888 directory on host is made directly accessible by guest as a pass-through 1889 file system by using the 9P network protocol for communication between 1890 host and guests, if desired even accessible, shared by several guests 1891 simultaneously. 1892 1893 Note that ``-virtfs`` is actually just a convenience shortcut for its 1894 generalized form ``-fsdev -device virtio-9p-pci``. 1895 1896 The general form of pass-through file system options are: 1897 1898 ``local`` 1899 Accesses to the filesystem are done by QEMU. 1900 1901 ``proxy`` 1902 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1903 This option is deprecated (since QEMU 8.1) and will be removed in a 1904 future version of QEMU. Use ``local`` instead. 1905 1906 ``synth`` 1907 Synthetic filesystem, only used by QTests. 1908 1909 ``id=id`` 1910 Specifies identifier for the filesystem device 1911 1912 ``path=path`` 1913 Specifies the export path for the file system device. Files 1914 under this path will be available to the 9p client on the guest. 1915 1916 ``security_model=security_model`` 1917 Specifies the security model to be used for this export path. 1918 Supported security models are "passthrough", "mapped-xattr", 1919 "mapped-file" and "none". In "passthrough" security model, files 1920 are stored using the same credentials as they are created on the 1921 guest. This requires QEMU to run as root. In "mapped-xattr" 1922 security model, some of the file attributes like uid, gid, mode 1923 bits and link target are stored as file attributes. For 1924 "mapped-file" these attributes are stored in the hidden 1925 .virtfs\_metadata directory. Directories exported by this 1926 security model cannot interact with other unix tools. "none" 1927 security model is same as passthrough except the sever won't 1928 report failures if it fails to set file attributes like 1929 ownership. Security model is mandatory only for local fsdriver. 1930 Other fsdrivers (like proxy) don't take security model as a 1931 parameter. 1932 1933 ``writeout=writeout`` 1934 This is an optional argument. The only supported value is 1935 "immediate". This means that host page cache will be used to 1936 read and write data but write notification will be sent to the 1937 guest only when the data has been reported as written by the 1938 storage subsystem. 1939 1940 ``readonly=on`` 1941 Enables exporting 9p share as a readonly mount for guests. By 1942 default read-write access is given. 1943 1944 ``socket=socket`` 1945 Enables proxy filesystem driver to use passed socket file for 1946 communicating with virtfs-proxy-helper(1). Usually a helper like 1947 libvirt will create socketpair and pass one of the fds as 1948 sock\_fd. 1949 1950 ``sock_fd`` 1951 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1952 socket descriptor for interfacing with virtfs-proxy-helper(1). 1953 1954 ``fmode=fmode`` 1955 Specifies the default mode for newly created files on the host. 1956 Works only with security models "mapped-xattr" and 1957 "mapped-file". 1958 1959 ``dmode=dmode`` 1960 Specifies the default mode for newly created directories on the 1961 host. Works only with security models "mapped-xattr" and 1962 "mapped-file". 1963 1964 ``mount_tag=mount_tag`` 1965 Specifies the tag name to be used by the guest to mount this 1966 export point. 1967 1968 ``multidevs=multidevs`` 1969 Specifies how to deal with multiple devices being shared with a 1970 9p export. Supported behaviours are either "remap", "forbid" or 1971 "warn". The latter is the default behaviour on which virtfs 9p 1972 expects only one device to be shared with the same export, and 1973 if more than one device is shared and accessed via the same 9p 1974 export then only a warning message is logged (once) by qemu on 1975 host side. In order to avoid file ID collisions on guest you 1976 should either create a separate virtfs export for each device to 1977 be shared with guests (recommended way) or you might use "remap" 1978 instead which allows you to share multiple devices with only one 1979 export instead, which is achieved by remapping the original 1980 inode numbers from host to guest in a way that would prevent 1981 such collisions. Remapping inodes in such use cases is required 1982 because the original device IDs from host are never passed and 1983 exposed on guest. Instead all files of an export shared with 1984 virtfs always share the same device id on guest. So two files 1985 with identical inode numbers but from actually different devices 1986 on host would otherwise cause a file ID collision and hence 1987 potential misbehaviours on guest. "forbid" on the other hand 1988 assumes like "warn" that only one device is shared by the same 1989 export, however it will not only log a warning message but also 1990 deny access to additional devices on guest. Note though that 1991 "forbid" does currently not block all possible file access 1992 operations (e.g. readdir() would still return entries from other 1993 devices). 1994ERST 1995 1996DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1997 "-iscsi [user=user][,password=password][,password-secret=secret-id]\n" 1998 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE]\n" 1999 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 2000 " [,timeout=timeout]\n" 2001 " iSCSI session parameters\n", QEMU_ARCH_ALL) 2002 2003SRST 2004``-iscsi`` 2005 Configure iSCSI session parameters. 2006ERST 2007 2008DEFHEADING() 2009 2010DEFHEADING(USB convenience options:) 2011 2012DEF("usb", 0, QEMU_OPTION_usb, 2013 "-usb enable on-board USB host controller (if not enabled by default)\n", 2014 QEMU_ARCH_ALL) 2015SRST 2016``-usb`` 2017 Enable USB emulation on machine types with an on-board USB host 2018 controller (if not enabled by default). Note that on-board USB host 2019 controllers may not support USB 3.0. In this case 2020 ``-device qemu-xhci`` can be used instead on machines with PCI. 2021ERST 2022 2023DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 2024 "-usbdevice name add the host or guest USB device 'name'\n", 2025 QEMU_ARCH_ALL) 2026SRST 2027``-usbdevice devname`` 2028 Add the USB device devname, and enable an on-board USB controller 2029 if possible and necessary (just like it can be done via 2030 ``-machine usb=on``). Note that this option is mainly intended for 2031 the user's convenience only. More fine-grained control can be 2032 achieved by selecting a USB host controller (if necessary) and the 2033 desired USB device via the ``-device`` option instead. For example, 2034 instead of using ``-usbdevice mouse`` it is possible to use 2035 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 2036 to a USB 3.0 controller instead (at least on machines that support 2037 PCI and do not have an USB controller enabled by default yet). 2038 For more details, see the chapter about 2039 :ref:`Connecting USB devices` in the System Emulation Users Guide. 2040 Possible devices for devname are: 2041 2042 ``braille`` 2043 Braille device. This will use BrlAPI to display the braille 2044 output on a real or fake device (i.e. it also creates a 2045 corresponding ``braille`` chardev automatically beside the 2046 ``usb-braille`` USB device). 2047 2048 ``keyboard`` 2049 Standard USB keyboard. Will override the PS/2 keyboard (if present). 2050 2051 ``mouse`` 2052 Virtual Mouse. This will override the PS/2 mouse emulation when 2053 activated. 2054 2055 ``tablet`` 2056 Pointer device that uses absolute coordinates (like a 2057 touchscreen). This means QEMU is able to report the mouse 2058 position without having to grab the mouse. Also overrides the 2059 PS/2 mouse emulation when activated. 2060 2061 ``wacom-tablet`` 2062 Wacom PenPartner USB tablet. 2063 2064 2065ERST 2066 2067DEFHEADING() 2068 2069DEFHEADING(Display options:) 2070 2071DEF("display", HAS_ARG, QEMU_OPTION_display, 2072#if defined(CONFIG_SPICE) 2073 "-display spice-app[,gl=on|off]\n" 2074#endif 2075#if defined(CONFIG_SDL) 2076 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 2077 " [,window-close=on|off]\n" 2078#endif 2079#if defined(CONFIG_GTK) 2080 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 2081 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 2082 " [,show-menubar=on|off]\n" 2083#endif 2084#if defined(CONFIG_VNC) 2085 "-display vnc=<display>[,<optargs>]\n" 2086#endif 2087#if defined(CONFIG_CURSES) 2088 "-display curses[,charset=<encoding>]\n" 2089#endif 2090#if defined(CONFIG_COCOA) 2091 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 2092 " [,show-cursor=on|off][,left-command-key=on|off]\n" 2093 " [,full-screen=on|off][,zoom-to-fit=on|off]\n" 2094#endif 2095#if defined(CONFIG_OPENGL) 2096 "-display egl-headless[,rendernode=<file>]\n" 2097#endif 2098#if defined(CONFIG_DBUS_DISPLAY) 2099 "-display dbus[,addr=<dbusaddr>]\n" 2100 " [,gl=on|core|es|off][,rendernode=<file>]\n" 2101#endif 2102 "-display none\n" 2103 " select display backend type\n" 2104 " The default display is equivalent to\n " 2105#if defined(CONFIG_GTK) 2106 "\"-display gtk\"\n" 2107#elif defined(CONFIG_SDL) 2108 "\"-display sdl\"\n" 2109#elif defined(CONFIG_COCOA) 2110 "\"-display cocoa\"\n" 2111#elif defined(CONFIG_VNC) 2112 "\"-vnc localhost:0,to=99,id=default\"\n" 2113#else 2114 "\"-display none\"\n" 2115#endif 2116 , QEMU_ARCH_ALL) 2117SRST 2118``-display type`` 2119 Select type of display to use. Use ``-display help`` to list the available 2120 display types. Valid values for type are 2121 2122 ``spice-app[,gl=on|off]`` 2123 Start QEMU as a Spice server and launch the default Spice client 2124 application. The Spice server will redirect the serial consoles 2125 and QEMU monitors. (Since 4.0) 2126 2127 ``dbus`` 2128 Export the display over D-Bus interfaces. (Since 7.0) 2129 2130 The connection is registered with the "org.qemu" name (and queued when 2131 already owned). 2132 2133 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2134 2135 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2136 2137 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2138 will share framebuffers with DMABUF file descriptors). 2139 2140 ``sdl`` 2141 Display video output via SDL (usually in a separate graphics 2142 window; see the SDL documentation for other possibilities). 2143 Valid parameters are: 2144 2145 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2146 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2147 either ``lshift-lctrl-lalt`` or ``rctrl``. 2148 2149 ``gl=on|off|core|es`` : Use OpenGL for displaying 2150 2151 ``show-cursor=on|off`` : Force showing the mouse cursor 2152 2153 ``window-close=on|off`` : Allow to quit qemu with window close button 2154 2155 ``gtk`` 2156 Display video output in a GTK window. This interface provides 2157 drop-down menus and other UI elements to configure and control 2158 the VM during runtime. Valid parameters are: 2159 2160 ``full-screen=on|off`` : Start in fullscreen mode 2161 2162 ``gl=on|off`` : Use OpenGL for displaying 2163 2164 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2165 2166 ``show-tabs=on|off`` : Display the tab bar for switching between the 2167 various graphical interfaces (e.g. VGA and 2168 virtual console character devices) by default. 2169 2170 ``show-cursor=on|off`` : Force showing the mouse cursor 2171 2172 ``window-close=on|off`` : Allow to quit qemu with window close button 2173 2174 ``show-menubar=on|off`` : Display the main window menubar, defaults to "on" 2175 2176 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2177 defaults to "off" 2178 2179 ``curses[,charset=<encoding>]`` 2180 Display video output via curses. For graphics device models 2181 which support a text mode, QEMU can display this output using a 2182 curses/ncurses interface. Nothing is displayed when the graphics 2183 device is in graphical mode or if the graphics device does not 2184 support a text mode. Generally only the VGA device models 2185 support text mode. The font charset used by the guest can be 2186 specified with the ``charset`` option, for example 2187 ``charset=CP850`` for IBM CP850 encoding. The default is 2188 ``CP437``. 2189 2190 ``cocoa`` 2191 Display video output in a Cocoa window. Mac only. This interface 2192 provides drop-down menus and other UI elements to configure and 2193 control the VM during runtime. Valid parameters are: 2194 2195 ``full-grab=on|off`` : Capture all key presses, including system combos. 2196 This requires accessibility permissions, since it 2197 performs a global grab on key events. 2198 (default: off) See 2199 https://support.apple.com/en-in/guide/mac-help/mh32356/mac 2200 2201 ``swap-opt-cmd=on|off`` : Swap the Option and Command keys so that their 2202 key codes match their position on non-Mac 2203 keyboards and you can use Meta/Super and Alt 2204 where you expect them. (default: off) 2205 2206 ``show-cursor=on|off`` : Force showing the mouse cursor 2207 2208 ``left-command-key=on|off`` : Disable forwarding left command key to host 2209 2210 ``full-screen=on|off`` : Start in fullscreen mode 2211 2212 ``zoom-to-fit=on|off`` : Expand video output to the window size, 2213 defaults to "off" 2214 2215 ``egl-headless[,rendernode=<file>]`` 2216 Offload all OpenGL operations to a local DRI device. For any 2217 graphical display, this display needs to be paired with either 2218 VNC or SPICE displays. 2219 2220 ``vnc=<display>`` 2221 Start a VNC server on display <display> 2222 2223 ``none`` 2224 Do not display video output. The guest will still see an 2225 emulated graphics card, but its output will not be displayed to 2226 the QEMU user. This option differs from the -nographic option in 2227 that it only affects what is done with video output; -nographic 2228 also changes the destination of the serial and parallel port 2229 data. 2230ERST 2231 2232DEF("nographic", 0, QEMU_OPTION_nographic, 2233 "-nographic disable graphical output and redirect serial I/Os to console\n", 2234 QEMU_ARCH_ALL) 2235SRST 2236``-nographic`` 2237 Normally, if QEMU is compiled with graphical window support, it 2238 displays output such as guest graphics, guest console, and the QEMU 2239 monitor in a window. With this option, you can totally disable 2240 graphical output so that QEMU is a simple command line application. 2241 The emulated serial port is redirected on the console and muxed with 2242 the monitor (unless redirected elsewhere explicitly). Therefore, you 2243 can still use QEMU to debug a Linux kernel with a serial console. 2244 Use C-a h for help on switching between the console and monitor. 2245ERST 2246 2247#ifdef CONFIG_SPICE 2248DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2249 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2250 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2251 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2252 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2253 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2254 " [,tls-ciphers=<list>]\n" 2255 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2256 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2257 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2258 " [,password-secret=<secret-id>]\n" 2259 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2260 " [,jpeg-wan-compression=[auto|never|always]]\n" 2261 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2262 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2263 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2264 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2265 " [,gl=[on|off]][,rendernode=<file>]\n" 2266 " enable spice\n" 2267 " at least one of {port, tls-port} is mandatory\n", 2268 QEMU_ARCH_ALL) 2269#endif 2270SRST 2271``-spice option[,option[,...]]`` 2272 Enable the spice remote desktop protocol. Valid options are 2273 2274 ``port=<nr>`` 2275 Set the TCP port spice is listening on for plaintext channels. 2276 2277 ``addr=<addr>`` 2278 Set the IP address spice is listening on. Default is any 2279 address. 2280 2281 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2282 Force using the specified IP version. 2283 2284 ``password-secret=<secret-id>`` 2285 Set the ID of the ``secret`` object containing the password 2286 you need to authenticate. 2287 2288 ``sasl=on|off`` 2289 Require that the client use SASL to authenticate with the spice. 2290 The exact choice of authentication method used is controlled 2291 from the system / user's SASL configuration file for the 'qemu' 2292 service. This is typically found in /etc/sasl2/qemu.conf. If 2293 running QEMU as an unprivileged user, an environment variable 2294 SASL\_CONF\_PATH can be used to make it search alternate 2295 locations for the service config. While some SASL auth methods 2296 can also provide data encryption (eg GSSAPI), it is recommended 2297 that SASL always be combined with the 'tls' and 'x509' settings 2298 to enable use of SSL and server certificates. This ensures a 2299 data encryption preventing compromise of authentication 2300 credentials. 2301 2302 ``disable-ticketing=on|off`` 2303 Allow client connects without authentication. 2304 2305 ``disable-copy-paste=on|off`` 2306 Disable copy paste between the client and the guest. 2307 2308 ``disable-agent-file-xfer=on|off`` 2309 Disable spice-vdagent based file-xfer between the client and the 2310 guest. 2311 2312 ``tls-port=<nr>`` 2313 Set the TCP port spice is listening on for encrypted channels. 2314 2315 ``x509-dir=<dir>`` 2316 Set the x509 file directory. Expects same filenames as -vnc 2317 $display,x509=$dir 2318 2319 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2320 The x509 file names can also be configured individually. 2321 2322 ``tls-ciphers=<list>`` 2323 Specify which ciphers to use. 2324 2325 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2326 Force specific channel to be used with or without TLS 2327 encryption. The options can be specified multiple times to 2328 configure multiple channels. The special name "default" can be 2329 used to set the default mode. For channels which are not 2330 explicitly forced into one mode the spice client is allowed to 2331 pick tls/plaintext as he pleases. 2332 2333 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2334 Configure image compression (lossless). Default is auto\_glz. 2335 2336 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2337 Configure wan image compression (lossy for slow links). Default 2338 is auto. 2339 2340 ``streaming-video=[off|all|filter]`` 2341 Configure video stream detection. Default is off. 2342 2343 ``agent-mouse=[on|off]`` 2344 Enable/disable passing mouse events via vdagent. Default is on. 2345 2346 ``playback-compression=[on|off]`` 2347 Enable/disable audio stream compression (using celt 0.5.1). 2348 Default is on. 2349 2350 ``seamless-migration=[on|off]`` 2351 Enable/disable spice seamless migration. Default is off. 2352 2353 ``gl=[on|off]`` 2354 Enable/disable OpenGL context. Default is off. 2355 2356 ``rendernode=<file>`` 2357 DRM render node for OpenGL rendering. If not specified, it will 2358 pick the first available. (Since 2.9) 2359ERST 2360 2361DEF("portrait", 0, QEMU_OPTION_portrait, 2362 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2363 QEMU_ARCH_ALL) 2364SRST 2365``-portrait`` 2366 Rotate graphical output 90 deg left (only PXA LCD). 2367ERST 2368 2369DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2370 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2371 QEMU_ARCH_ALL) 2372SRST 2373``-rotate deg`` 2374 Rotate graphical output some deg left (only PXA LCD). 2375ERST 2376 2377DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2378 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2379 " select video card type\n", QEMU_ARCH_ALL) 2380SRST 2381``-vga type`` 2382 Select type of VGA card to emulate. Valid values for type are 2383 2384 ``cirrus`` 2385 Cirrus Logic GD5446 Video card. All Windows versions starting 2386 from Windows 95 should recognize and use this graphic card. For 2387 optimal performances, use 16 bit color depth in the guest and 2388 the host OS. (This card was the default before QEMU 2.2) 2389 2390 ``std`` 2391 Standard VGA card with Bochs VBE extensions. If your guest OS 2392 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2393 you want to use high resolution modes (>= 1280x1024x16) then you 2394 should use this option. (This card is the default since QEMU 2395 2.2) 2396 2397 ``vmware`` 2398 VMWare SVGA-II compatible adapter. Use it if you have 2399 sufficiently recent XFree86/XOrg server or Windows guest with a 2400 driver for this card. 2401 2402 ``qxl`` 2403 QXL paravirtual graphic card. It is VGA compatible (including 2404 VESA 2.0 VBE support). Works best with qxl guest drivers 2405 installed though. Recommended choice when using the spice 2406 protocol. 2407 2408 ``tcx`` 2409 (sun4m only) Sun TCX framebuffer. This is the default 2410 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2411 colour depths at a fixed resolution of 1024x768. 2412 2413 ``cg3`` 2414 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2415 framebuffer for sun4m machines available in both 1024x768 2416 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2417 wishing to run older Solaris versions. 2418 2419 ``virtio`` 2420 Virtio VGA card. 2421 2422 ``none`` 2423 Disable VGA card. 2424ERST 2425 2426DEF("full-screen", 0, QEMU_OPTION_full_screen, 2427 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2428SRST 2429``-full-screen`` 2430 Start in full screen. 2431ERST 2432 2433DEF("g", HAS_ARG, QEMU_OPTION_g , 2434 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2435 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2436SRST 2437``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2438 Set the initial graphical resolution and depth (PPC, SPARC only). 2439 2440 For PPC the default is 800x600x32. 2441 2442 For SPARC with the TCX graphics device, the default is 1024x768x8 2443 with the option of 1024x768x24. For cgthree, the default is 2444 1024x768x8 with the option of 1152x900x8 for people who wish to use 2445 OBP. 2446ERST 2447 2448#ifdef CONFIG_VNC 2449DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2450 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2451#endif 2452SRST 2453``-vnc display[,option[,option[,...]]]`` 2454 Normally, if QEMU is compiled with graphical window support, it 2455 displays output such as guest graphics, guest console, and the QEMU 2456 monitor in a window. With this option, you can have QEMU listen on 2457 VNC display display and redirect the VGA display over the VNC 2458 session. It is very useful to enable the usb tablet device when 2459 using this option (option ``-device usb-tablet``). When using the 2460 VNC display, you must use the ``-k`` parameter to set the keyboard 2461 layout if you are not using en-us. Valid syntax for the display is 2462 2463 ``to=L`` 2464 With this option, QEMU will try next available VNC displays, 2465 until the number L, if the origianlly defined "-vnc display" is 2466 not available, e.g. port 5900+display is already used by another 2467 application. By default, to=0. 2468 2469 ``host:d`` 2470 TCP connections will only be allowed from host on display d. By 2471 convention the TCP port is 5900+d. Optionally, host can be 2472 omitted in which case the server will accept connections from 2473 any host. 2474 2475 ``unix:path`` 2476 Connections will be allowed over UNIX domain sockets where path 2477 is the location of a unix socket to listen for connections on. 2478 2479 ``none`` 2480 VNC is initialized but not started. The monitor ``change`` 2481 command can be used to later start the VNC server. 2482 2483 Following the display value there may be one or more option flags 2484 separated by commas. Valid options are 2485 2486 ``reverse=on|off`` 2487 Connect to a listening VNC client via a "reverse" connection. 2488 The client is specified by the display. For reverse network 2489 connections (host:d,``reverse``), the d argument is a TCP port 2490 number, not a display number. 2491 2492 ``websocket=on|off`` 2493 Opens an additional TCP listening port dedicated to VNC 2494 Websocket connections. If a bare websocket option is given, the 2495 Websocket port is 5700+display. An alternative port can be 2496 specified with the syntax ``websocket``\ =port. 2497 2498 If host is specified connections will only be allowed from this 2499 host. It is possible to control the websocket listen address 2500 independently, using the syntax ``websocket``\ =host:port. 2501 2502 If no TLS credentials are provided, the websocket connection 2503 runs in unencrypted mode. If TLS credentials are provided, the 2504 websocket connection requires encrypted client connections. 2505 2506 ``password=on|off`` 2507 Require that password based authentication is used for client 2508 connections. 2509 2510 The password must be set separately using the ``set_password`` 2511 command in the :ref:`QEMU monitor`. The 2512 syntax to change your password is: 2513 ``set_password <protocol> <password>`` where <protocol> could be 2514 either "vnc" or "spice". 2515 2516 If you would like to change <protocol> password expiration, you 2517 should use ``expire_password <protocol> <expiration-time>`` 2518 where expiration time could be one of the following options: 2519 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2520 make password expire in 60 seconds, or 1335196800 to make 2521 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2522 this date and time). 2523 2524 You can also use keywords "now" or "never" for the expiration 2525 time to allow <protocol> password to expire immediately or never 2526 expire. 2527 2528 ``password-secret=<secret-id>`` 2529 Require that password based authentication is used for client 2530 connections, using the password provided by the ``secret`` 2531 object identified by ``secret-id``. 2532 2533 ``tls-creds=ID`` 2534 Provides the ID of a set of TLS credentials to use to secure the 2535 VNC server. They will apply to both the normal VNC server socket 2536 and the websocket socket (if enabled). Setting TLS credentials 2537 will cause the VNC server socket to enable the VeNCrypt auth 2538 mechanism. The credentials should have been previously created 2539 using the ``-object tls-creds`` argument. 2540 2541 ``tls-authz=ID`` 2542 Provides the ID of the QAuthZ authorization object against which 2543 the client's x509 distinguished name will validated. This object 2544 is only resolved at time of use, so can be deleted and recreated 2545 on the fly while the VNC server is active. If missing, it will 2546 default to denying access. 2547 2548 ``sasl=on|off`` 2549 Require that the client use SASL to authenticate with the VNC 2550 server. The exact choice of authentication method used is 2551 controlled from the system / user's SASL configuration file for 2552 the 'qemu' service. This is typically found in 2553 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2554 an environment variable SASL\_CONF\_PATH can be used to make it 2555 search alternate locations for the service config. While some 2556 SASL auth methods can also provide data encryption (eg GSSAPI), 2557 it is recommended that SASL always be combined with the 'tls' 2558 and 'x509' settings to enable use of SSL and server 2559 certificates. This ensures a data encryption preventing 2560 compromise of authentication credentials. See the 2561 :ref:`VNC security` section in the System Emulation Users Guide 2562 for details on using SASL authentication. 2563 2564 ``sasl-authz=ID`` 2565 Provides the ID of the QAuthZ authorization object against which 2566 the client's SASL username will validated. This object is only 2567 resolved at time of use, so can be deleted and recreated on the 2568 fly while the VNC server is active. If missing, it will default 2569 to denying access. 2570 2571 ``acl=on|off`` 2572 Legacy method for enabling authorization of clients against the 2573 x509 distinguished name and SASL username. It results in the 2574 creation of two ``authz-list`` objects with IDs of 2575 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2576 objects must be configured with the HMP ACL commands. 2577 2578 This option is deprecated and should no longer be used. The new 2579 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2580 2581 ``lossy=on|off`` 2582 Enable lossy compression methods (gradient, JPEG, ...). If this 2583 option is set, VNC client may receive lossy framebuffer updates 2584 depending on its encoding settings. Enabling this option can 2585 save a lot of bandwidth at the expense of quality. 2586 2587 ``non-adaptive=on|off`` 2588 Disable adaptive encodings. Adaptive encodings are enabled by 2589 default. An adaptive encoding will try to detect frequently 2590 updated screen regions, and send updates in these regions using 2591 a lossy encoding (like JPEG). This can be really helpful to save 2592 bandwidth when playing videos. Disabling adaptive encodings 2593 restores the original static behavior of encodings like Tight. 2594 2595 ``share=[allow-exclusive|force-shared|ignore]`` 2596 Set display sharing policy. 'allow-exclusive' allows clients to 2597 ask for exclusive access. As suggested by the rfb spec this is 2598 implemented by dropping other connections. Connecting multiple 2599 clients in parallel requires all clients asking for a shared 2600 session (vncviewer: -shared switch). This is the default. 2601 'force-shared' disables exclusive client access. Useful for 2602 shared desktop sessions, where you don't want someone forgetting 2603 specify -shared disconnect everybody else. 'ignore' completely 2604 ignores the shared flag and allows everybody connect 2605 unconditionally. Doesn't conform to the rfb spec but is 2606 traditional QEMU behavior. 2607 2608 ``key-delay-ms`` 2609 Set keyboard delay, for key down and key up events, in 2610 milliseconds. Default is 10. Keyboards are low-bandwidth 2611 devices, so this slowdown can help the device and guest to keep 2612 up and not lose events in case events are arriving in bulk. 2613 Possible causes for the latter are flaky network connections, or 2614 scripts for automated testing. 2615 2616 ``audiodev=audiodev`` 2617 Use the specified audiodev when the VNC client requests audio 2618 transmission. When not using an -audiodev argument, this option 2619 must be omitted, otherwise is must be present and specify a 2620 valid audiodev. 2621 2622 ``power-control=on|off`` 2623 Permit the remote client to issue shutdown, reboot or reset power 2624 control requests. 2625ERST 2626 2627ARCHHEADING(, QEMU_ARCH_I386) 2628 2629ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2630 2631DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2632 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2633 QEMU_ARCH_I386) 2634SRST 2635``-win2k-hack`` 2636 Use it when installing Windows 2000 to avoid a disk full bug. After 2637 Windows 2000 is installed, you no longer need this option (this 2638 option slows down the IDE transfers). 2639ERST 2640 2641DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2642 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2643 QEMU_ARCH_I386) 2644SRST 2645``-no-fd-bootchk`` 2646 Disable boot signature checking for floppy disks in BIOS. May be 2647 needed to boot from old floppy disks. 2648ERST 2649 2650DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2651 "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]\n" 2652 " ACPI table description\n", QEMU_ARCH_I386) 2653SRST 2654``-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n] [,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]`` 2655 Add ACPI table with specified header fields and context from 2656 specified files. For file=, take whole ACPI table from the specified 2657 files, including all ACPI headers (possible overridden by other 2658 options). For data=, only data portion of the table is used, all 2659 header information is specified in the command line. If a SLIC table 2660 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2661 fields will override the same in the RSDT and the FADT (a.k.a. 2662 FACP), in order to ensure the field matches required by the 2663 Microsoft SLIC spec and the ACPI spec. 2664ERST 2665 2666DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2667 "-smbios file=binary\n" 2668 " load SMBIOS entry from binary file\n" 2669 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2670 " [,uefi=on|off]\n" 2671 " specify SMBIOS type 0 fields\n" 2672 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2673 " [,uuid=uuid][,sku=str][,family=str]\n" 2674 " specify SMBIOS type 1 fields\n" 2675 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2676 " [,asset=str][,location=str]\n" 2677 " specify SMBIOS type 2 fields\n" 2678 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2679 " [,sku=str]\n" 2680 " specify SMBIOS type 3 fields\n" 2681 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2682 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2683 " [,processor-id=%d]\n" 2684 " specify SMBIOS type 4 fields\n" 2685 "-smbios type=8[,external_reference=str][,internal_reference=str][,connector_type=%d][,port_type=%d]\n" 2686 " specify SMBIOS type 8 fields\n" 2687 "-smbios type=11[,value=str][,path=filename]\n" 2688 " specify SMBIOS type 11 fields\n" 2689 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2690 " [,asset=str][,part=str][,speed=%d]\n" 2691 " specify SMBIOS type 17 fields\n" 2692 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2693 " specify SMBIOS type 41 fields\n", 2694 QEMU_ARCH_I386 | QEMU_ARCH_ARM | QEMU_ARCH_LOONGARCH) 2695SRST 2696``-smbios file=binary`` 2697 Load SMBIOS entry from binary file. 2698 2699``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2700 Specify SMBIOS type 0 fields 2701 2702``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2703 Specify SMBIOS type 1 fields 2704 2705``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2706 Specify SMBIOS type 2 fields 2707 2708``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2709 Specify SMBIOS type 3 fields 2710 2711``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2712 Specify SMBIOS type 4 fields 2713 2714``-smbios type=11[,value=str][,path=filename]`` 2715 Specify SMBIOS type 11 fields 2716 2717 This argument can be repeated multiple times, and values are added in the order they are parsed. 2718 Applications intending to use OEM strings data are encouraged to use their application name as 2719 a prefix for the value string. This facilitates passing information for multiple applications 2720 concurrently. 2721 2722 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2723 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2724 2725 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2726 the SMBIOS table in the order in which they appear. 2727 2728 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2729 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2730 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2731 data set, for example, by specifying the serial ID of a block device. 2732 2733 An example passing three strings is 2734 2735 .. parsed-literal:: 2736 2737 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2738 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2739 path=/some/file/with/oemstringsdata.txt 2740 2741 In the guest OS this is visible with the ``dmidecode`` command 2742 2743 .. parsed-literal:: 2744 2745 $ dmidecode -t 11 2746 Handle 0x0E00, DMI type 11, 5 bytes 2747 OEM Strings 2748 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2749 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2750 String 3: myapp:some extra data 2751 2752 2753``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2754 Specify SMBIOS type 17 fields 2755 2756``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2757 Specify SMBIOS type 41 fields 2758 2759 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2760 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2761 position on the PCI bus. 2762 2763 Here is an example of use: 2764 2765 .. parsed-literal:: 2766 2767 -netdev user,id=internet \\ 2768 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2769 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2770 2771 In the guest OS, the device should then appear as ``eno1``: 2772 2773 ..parsed-literal:: 2774 2775 $ ip -brief l 2776 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2777 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2778 2779 Currently, the PCI device has to be attached to the root bus. 2780 2781ERST 2782 2783DEFHEADING() 2784 2785DEFHEADING(Network options:) 2786 2787DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2788#ifdef CONFIG_SLIRP 2789 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2790 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2791 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2792 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2793 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2794#ifndef _WIN32 2795 "[,smb=dir[,smbserver=addr]]\n" 2796#endif 2797 " configure a user mode network backend with ID 'str',\n" 2798 " its DHCP server and optional services\n" 2799#endif 2800#ifdef _WIN32 2801 "-netdev tap,id=str,ifname=name\n" 2802 " configure a host TAP network backend with ID 'str'\n" 2803#else 2804 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2805 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2806 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2807 " [,poll-us=n]\n" 2808 " configure a host TAP network backend with ID 'str'\n" 2809 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2810 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2811 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2812 " to deconfigure it\n" 2813 " use '[down]script=no' to disable script execution\n" 2814 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2815 " configure it\n" 2816 " use 'fd=h' to connect to an already opened TAP interface\n" 2817 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2818 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2819 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2820 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2821 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2822 " use vhost=on to enable experimental in kernel accelerator\n" 2823 " (only has effect for virtio guests which use MSIX)\n" 2824 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2825 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2826 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2827 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2828 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2829 " spent on busy polling for vhost net\n" 2830 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2831 " configure a host TAP network backend with ID 'str' that is\n" 2832 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2833 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2834#endif 2835#ifdef __linux__ 2836 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2837 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2838 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2839 " [,rxcookie=rxcookie][,offset=offset]\n" 2840 " configure a network backend with ID 'str' connected to\n" 2841 " an Ethernet over L2TPv3 pseudowire.\n" 2842 " Linux kernel 3.3+ as well as most routers can talk\n" 2843 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2844 " VM to a router and even VM to Host. It is a nearly-universal\n" 2845 " standard (RFC3931). Note - this implementation uses static\n" 2846 " pre-configured tunnels (same as the Linux kernel).\n" 2847 " use 'src=' to specify source address\n" 2848 " use 'dst=' to specify destination address\n" 2849 " use 'udp=on' to specify udp encapsulation\n" 2850 " use 'srcport=' to specify source udp port\n" 2851 " use 'dstport=' to specify destination udp port\n" 2852 " use 'ipv6=on' to force v6\n" 2853 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2854 " well as a weak security measure\n" 2855 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2856 " use 'txcookie=0x012345678' to specify a txcookie\n" 2857 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2858 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2859 " use 'pincounter=on' to work around broken counter handling in peer\n" 2860 " use 'offset=X' to add an extra offset between header and data\n" 2861#endif 2862 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2863 " configure a network backend to connect to another network\n" 2864 " using a socket connection\n" 2865 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2866 " configure a network backend to connect to a multicast maddr and port\n" 2867 " use 'localaddr=addr' to specify the host address to send packets from\n" 2868 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2869 " configure a network backend to connect to another network\n" 2870 " using an UDP tunnel\n" 2871 "-netdev stream,id=str[,server=on|off],addr.type=inet,addr.host=host,addr.port=port[,to=maxport][,numeric=on|off][,keep-alive=on|off][,mptcp=on|off][,addr.ipv4=on|off][,addr.ipv6=on|off][,reconnect=seconds]\n" 2872 "-netdev stream,id=str[,server=on|off],addr.type=unix,addr.path=path[,abstract=on|off][,tight=on|off][,reconnect=seconds]\n" 2873 "-netdev stream,id=str[,server=on|off],addr.type=fd,addr.str=file-descriptor[,reconnect=seconds]\n" 2874 " configure a network backend to connect to another network\n" 2875 " using a socket connection in stream mode.\n" 2876 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=inet,local.host=addr]\n" 2877 "-netdev dgram,id=str,remote.type=inet,remote.host=maddr,remote.port=port[,local.type=fd,local.str=file-descriptor]\n" 2878 " configure a network backend to connect to a multicast maddr and port\n" 2879 " use ``local.host=addr`` to specify the host address to send packets from\n" 2880 "-netdev dgram,id=str,local.type=inet,local.host=addr,local.port=port[,remote.type=inet,remote.host=addr,remote.port=port]\n" 2881 "-netdev dgram,id=str,local.type=unix,local.path=path[,remote.type=unix,remote.path=path]\n" 2882 "-netdev dgram,id=str,local.type=fd,local.str=file-descriptor\n" 2883 " configure a network backend to connect to another network\n" 2884 " using an UDP tunnel\n" 2885#ifdef CONFIG_VDE 2886 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2887 " configure a network backend to connect to port 'n' of a vde switch\n" 2888 " running on host and listening for incoming connections on 'socketpath'.\n" 2889 " Use group 'groupname' and mode 'octalmode' to change default\n" 2890 " ownership and permissions for communication port.\n" 2891#endif 2892#ifdef CONFIG_NETMAP 2893 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2894 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2895 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2896 " netmap device, defaults to '/dev/netmap')\n" 2897#endif 2898#ifdef CONFIG_AF_XDP 2899 "-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off]\n" 2900 " [,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]\n" 2901 " attach to the existing network interface 'name' with AF_XDP socket\n" 2902 " use 'mode=MODE' to specify an XDP program attach mode\n" 2903 " use 'force-copy=on|off' to force XDP copy mode even if device supports zero-copy (default: off)\n" 2904 " use 'inhibit=on|off' to inhibit loading of a default XDP program (default: off)\n" 2905 " with inhibit=on,\n" 2906 " use 'sock-fds' to provide file descriptors for already open AF_XDP sockets\n" 2907 " added to a socket map in XDP program. One socket per queue.\n" 2908 " use 'queues=n' to specify how many queues of a multiqueue interface should be used\n" 2909 " use 'start-queue=m' to specify the first queue that should be used\n" 2910#endif 2911#ifdef CONFIG_POSIX 2912 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2913 " configure a vhost-user network, backed by a chardev 'dev'\n" 2914#endif 2915#ifdef __linux__ 2916 "-netdev vhost-vdpa,id=str[,vhostdev=/path/to/dev][,vhostfd=h]\n" 2917 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2918 " use 'vhostdev=/path/to/dev' to open a vhost vdpa device\n" 2919 " use 'vhostfd=h' to connect to an already opened vhost vdpa device\n" 2920#endif 2921#ifdef CONFIG_VMNET 2922 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2923 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2924 " configure a vmnet network backend in host mode with ID 'str',\n" 2925 " isolate this interface from others with 'isolated',\n" 2926 " configure the address range and choose a subnet mask,\n" 2927 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2928 " vmnet-host interfaces within this isolated network\n" 2929 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2930 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2931 " configure a vmnet network backend in shared mode with ID 'str',\n" 2932 " configure the address range and choose a subnet mask,\n" 2933 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2934 " isolate this interface from others with 'isolated'\n" 2935 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2936 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2937 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2938 " isolate this interface from others with 'isolated'\n" 2939#endif 2940 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2941 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2942DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2943 "-nic [tap|bridge|" 2944#ifdef CONFIG_SLIRP 2945 "user|" 2946#endif 2947#ifdef __linux__ 2948 "l2tpv3|" 2949#endif 2950#ifdef CONFIG_VDE 2951 "vde|" 2952#endif 2953#ifdef CONFIG_NETMAP 2954 "netmap|" 2955#endif 2956#ifdef CONFIG_AF_XDP 2957 "af-xdp|" 2958#endif 2959#ifdef CONFIG_POSIX 2960 "vhost-user|" 2961#endif 2962#ifdef CONFIG_VMNET 2963 "vmnet-host|vmnet-shared|vmnet-bridged|" 2964#endif 2965 "socket][,option][,...][mac=macaddr]\n" 2966 " initialize an on-board / default host NIC (using MAC address\n" 2967 " macaddr) and connect it to the given host network backend\n" 2968 "-nic none use it alone to have zero network devices (the default is to\n" 2969 " provided a 'user' network connection)\n", 2970 QEMU_ARCH_ALL) 2971DEF("net", HAS_ARG, QEMU_OPTION_net, 2972 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2973 " configure or create an on-board (or machine default) NIC and\n" 2974 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2975 "-net [" 2976#ifdef CONFIG_SLIRP 2977 "user|" 2978#endif 2979 "tap|" 2980 "bridge|" 2981#ifdef CONFIG_VDE 2982 "vde|" 2983#endif 2984#ifdef CONFIG_NETMAP 2985 "netmap|" 2986#endif 2987#ifdef CONFIG_AF_XDP 2988 "af-xdp|" 2989#endif 2990#ifdef CONFIG_VMNET 2991 "vmnet-host|vmnet-shared|vmnet-bridged|" 2992#endif 2993 "socket][,option][,option][,...]\n" 2994 " old way to initialize a host network interface\n" 2995 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2996SRST 2997``-nic [tap|bridge|user|l2tpv3|vde|netmap|af-xdp|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2998 This option is a shortcut for configuring both the on-board 2999 (default) guest NIC hardware and the host network backend in one go. 3000 The host backend options are the same as with the corresponding 3001 ``-netdev`` options below. The guest NIC model can be set with 3002 ``model=modelname``. Use ``model=help`` to list the available device 3003 types. The hardware MAC address can be set with ``mac=macaddr``. 3004 3005 The following two example do exactly the same, to show how ``-nic`` 3006 can be used to shorten the command line length: 3007 3008 .. parsed-literal:: 3009 3010 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 3011 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 3012 3013``-nic none`` 3014 Indicate that no network devices should be configured. It is used to 3015 override the default configuration (default NIC with "user" host 3016 network backend) which is activated if no other networking options 3017 are provided. 3018 3019``-netdev user,id=id[,option][,option][,...]`` 3020 Configure user mode host network backend which requires no 3021 administrator privilege to run. Valid options are: 3022 3023 ``id=id`` 3024 Assign symbolic name for use in monitor commands. 3025 3026 ``ipv4=on|off and ipv6=on|off`` 3027 Specify that either IPv4 or IPv6 must be enabled. If neither is 3028 specified both protocols are enabled. 3029 3030 ``net=addr[/mask]`` 3031 Set IP network address the guest will see. Optionally specify 3032 the netmask, either in the form a.b.c.d or as number of valid 3033 top-most bits. Default is 10.0.2.0/24. 3034 3035 ``host=addr`` 3036 Specify the guest-visible address of the host. Default is the 3037 2nd IP in the guest network, i.e. x.x.x.2. 3038 3039 ``ipv6-net=addr[/int]`` 3040 Set IPv6 network address the guest will see (default is 3041 fec0::/64). The network prefix is given in the usual hexadecimal 3042 IPv6 address notation. The prefix size is optional, and is given 3043 as the number of valid top-most bits (default is 64). 3044 3045 ``ipv6-host=addr`` 3046 Specify the guest-visible IPv6 address of the host. Default is 3047 the 2nd IPv6 in the guest network, i.e. xxxx::2. 3048 3049 ``restrict=on|off`` 3050 If this option is enabled, the guest will be isolated, i.e. it 3051 will not be able to contact the host and no guest IP packets 3052 will be routed over the host to the outside. This option does 3053 not affect any explicitly set forwarding rules. 3054 3055 ``hostname=name`` 3056 Specifies the client hostname reported by the built-in DHCP 3057 server. 3058 3059 ``dhcpstart=addr`` 3060 Specify the first of the 16 IPs the built-in DHCP server can 3061 assign. Default is the 15th to 31st IP in the guest network, 3062 i.e. x.x.x.15 to x.x.x.31. 3063 3064 ``dns=addr`` 3065 Specify the guest-visible address of the virtual nameserver. The 3066 address must be different from the host address. Default is the 3067 3rd IP in the guest network, i.e. x.x.x.3. 3068 3069 ``ipv6-dns=addr`` 3070 Specify the guest-visible address of the IPv6 virtual 3071 nameserver. The address must be different from the host address. 3072 Default is the 3rd IP in the guest network, i.e. xxxx::3. 3073 3074 ``dnssearch=domain`` 3075 Provides an entry for the domain-search list sent by the 3076 built-in DHCP server. More than one domain suffix can be 3077 transmitted by specifying this option multiple times. If 3078 supported, this will cause the guest to automatically try to 3079 append the given domain suffix(es) in case a domain name can not 3080 be resolved. 3081 3082 Example: 3083 3084 .. parsed-literal:: 3085 3086 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 3087 3088 ``domainname=domain`` 3089 Specifies the client domain name reported by the built-in DHCP 3090 server. 3091 3092 ``tftp=dir`` 3093 When using the user mode network stack, activate a built-in TFTP 3094 server. The files in dir will be exposed as the root of a TFTP 3095 server. The TFTP client on the guest must be configured in 3096 binary mode (use the command ``bin`` of the Unix TFTP client). 3097 3098 ``tftp-server-name=name`` 3099 In BOOTP reply, broadcast name as the "TFTP server name" 3100 (RFC2132 option 66). This can be used to advise the guest to 3101 load boot files or configurations from a different server than 3102 the host address. 3103 3104 ``bootfile=file`` 3105 When using the user mode network stack, broadcast file as the 3106 BOOTP filename. In conjunction with ``tftp``, this can be used 3107 to network boot a guest from a local directory. 3108 3109 Example (using pxelinux): 3110 3111 .. parsed-literal:: 3112 3113 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 3114 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 3115 3116 ``smb=dir[,smbserver=addr]`` 3117 When using the user mode network stack, activate a built-in SMB 3118 server so that Windows OSes can access to the host files in 3119 ``dir`` transparently. The IP address of the SMB server can be 3120 set to addr. By default the 4th IP in the guest network is used, 3121 i.e. x.x.x.4. 3122 3123 In the guest Windows OS, the line: 3124 3125 :: 3126 3127 10.0.2.4 smbserver 3128 3129 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 3130 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 3131 NT/2000). 3132 3133 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 3134 3135 Note that a SAMBA server must be installed on the host OS. 3136 3137 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 3138 Redirect incoming TCP or UDP connections to the host port 3139 hostport to the guest IP address guestaddr on guest port 3140 guestport. If guestaddr is not specified, its value is x.x.x.15 3141 (default first address given by the built-in DHCP server). By 3142 specifying hostaddr, the rule can be bound to a specific host 3143 interface. If no connection type is set, TCP is used. This 3144 option can be given multiple times. 3145 3146 For example, to redirect host X11 connection from screen 1 to 3147 guest screen 0, use the following: 3148 3149 .. parsed-literal:: 3150 3151 # on the host 3152 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3153 # this host xterm should open in the guest X11 server 3154 xterm -display :1 3155 3156 To redirect telnet connections from host port 5555 to telnet 3157 port on the guest, use the following: 3158 3159 .. parsed-literal:: 3160 3161 # on the host 3162 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3163 telnet localhost 5555 3164 3165 Then when you use on the host ``telnet localhost 5555``, you 3166 connect to the guest telnet server. 3167 3168 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3169 Forward guest TCP connections to the IP address server on port 3170 port to the character device dev or to a program executed by 3171 cmd:command which gets spawned for each connection. This option 3172 can be given multiple times. 3173 3174 You can either use a chardev directly and have that one used 3175 throughout QEMU's lifetime, like in the following example: 3176 3177 .. parsed-literal:: 3178 3179 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3180 # the guest accesses it 3181 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3182 3183 Or you can execute a command on every TCP connection established 3184 by the guest, so that QEMU behaves similar to an inetd process 3185 for that virtual server: 3186 3187 .. parsed-literal:: 3188 3189 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3190 # and connect the TCP stream to its stdin/stdout 3191 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3192 3193``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3194 Configure a host TAP network backend with ID id. 3195 3196 Use the network script file to configure it and the network script 3197 dfile to deconfigure it. If name is not provided, the OS 3198 automatically provides one. The default network configure script is 3199 ``/etc/qemu-ifup`` and the default network deconfigure script is 3200 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3201 disable script execution. 3202 3203 If running QEMU as an unprivileged user, use the network helper 3204 to configure the TAP interface and attach it to the bridge. 3205 The default network helper executable is 3206 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3207 ``br0``. 3208 3209 ``fd``\ =h can be used to specify the handle of an already opened 3210 host TAP interface. 3211 3212 Examples: 3213 3214 .. parsed-literal:: 3215 3216 #launch a QEMU instance with the default network script 3217 |qemu_system| linux.img -nic tap 3218 3219 .. parsed-literal:: 3220 3221 #launch a QEMU instance with two NICs, each one connected 3222 #to a TAP device 3223 |qemu_system| linux.img \\ 3224 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3225 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3226 3227 .. parsed-literal:: 3228 3229 #launch a QEMU instance with the default network helper to 3230 #connect a TAP device to bridge br0 3231 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3232 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3233 3234``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3235 Connect a host TAP network interface to a host bridge device. 3236 3237 Use the network helper helper to configure the TAP interface and 3238 attach it to the bridge. The default network helper executable is 3239 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3240 ``br0``. 3241 3242 Examples: 3243 3244 .. parsed-literal:: 3245 3246 #launch a QEMU instance with the default network helper to 3247 #connect a TAP device to bridge br0 3248 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3249 3250 .. parsed-literal:: 3251 3252 #launch a QEMU instance with the default network helper to 3253 #connect a TAP device to bridge qemubr0 3254 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3255 3256``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3257 This host network backend can be used to connect the guest's network 3258 to another QEMU virtual machine using a TCP socket connection. If 3259 ``listen`` is specified, QEMU waits for incoming connections on port 3260 (host is optional). ``connect`` is used to connect to another QEMU 3261 instance using the ``listen`` option. ``fd``\ =h specifies an 3262 already opened TCP socket. 3263 3264 Example: 3265 3266 .. parsed-literal:: 3267 3268 # launch a first QEMU instance 3269 |qemu_system| linux.img \\ 3270 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3271 -netdev socket,id=n1,listen=:1234 3272 # connect the network of this instance to the network of the first instance 3273 |qemu_system| linux.img \\ 3274 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3275 -netdev socket,id=n2,connect=127.0.0.1:1234 3276 3277``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3278 Configure a socket host network backend to share the guest's network 3279 traffic with another QEMU virtual machines using a UDP multicast 3280 socket, effectively making a bus for every QEMU with same multicast 3281 address maddr and port. NOTES: 3282 3283 1. Several QEMU can be running on different hosts and share same bus 3284 (assuming correct multicast setup for these hosts). 3285 3286 2. mcast support is compatible with User Mode Linux (argument 3287 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3288 3289 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3290 3291 Example: 3292 3293 .. parsed-literal:: 3294 3295 # launch one QEMU instance 3296 |qemu_system| linux.img \\ 3297 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3298 -netdev socket,id=n1,mcast=230.0.0.1:1234 3299 # launch another QEMU instance on same "bus" 3300 |qemu_system| linux.img \\ 3301 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3302 -netdev socket,id=n2,mcast=230.0.0.1:1234 3303 # launch yet another QEMU instance on same "bus" 3304 |qemu_system| linux.img \\ 3305 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3306 -netdev socket,id=n3,mcast=230.0.0.1:1234 3307 3308 Example (User Mode Linux compat.): 3309 3310 .. parsed-literal:: 3311 3312 # launch QEMU instance (note mcast address selected is UML's default) 3313 |qemu_system| linux.img \\ 3314 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3315 -netdev socket,id=n1,mcast=239.192.168.1:1102 3316 # launch UML 3317 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3318 3319 Example (send packets from host's 1.2.3.4): 3320 3321 .. parsed-literal:: 3322 3323 |qemu_system| linux.img \\ 3324 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3325 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3326 3327``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 3328 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3329 is a popular protocol to transport Ethernet (and other Layer 2) data 3330 frames between two systems. It is present in routers, firewalls and 3331 the Linux kernel (from version 3.3 onwards). 3332 3333 This transport allows a VM to communicate to another VM, router or 3334 firewall directly. 3335 3336 ``src=srcaddr`` 3337 source address (mandatory) 3338 3339 ``dst=dstaddr`` 3340 destination address (mandatory) 3341 3342 ``udp`` 3343 select udp encapsulation (default is ip). 3344 3345 ``srcport=srcport`` 3346 source udp port. 3347 3348 ``dstport=dstport`` 3349 destination udp port. 3350 3351 ``ipv6`` 3352 force v6, otherwise defaults to v4. 3353 3354 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3355 Cookies are a weak form of security in the l2tpv3 specification. 3356 Their function is mostly to prevent misconfiguration. By default 3357 they are 32 bit. 3358 3359 ``cookie64`` 3360 Set cookie size to 64 bit instead of the default 32 3361 3362 ``counter=off`` 3363 Force a 'cut-down' L2TPv3 with no counter as in 3364 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3365 3366 ``pincounter=on`` 3367 Work around broken counter handling in peer. This may also help 3368 on networks which have packet reorder. 3369 3370 ``offset=offset`` 3371 Add an extra offset between header and data 3372 3373 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3374 the bridge br-lan on the remote Linux host 1.2.3.4: 3375 3376 .. parsed-literal:: 3377 3378 # Setup tunnel on linux host using raw ip as encapsulation 3379 # on 1.2.3.4 3380 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3381 encap udp udp_sport 16384 udp_dport 16384 3382 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3383 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3384 ifconfig vmtunnel0 mtu 1500 3385 ifconfig vmtunnel0 up 3386 brctl addif br-lan vmtunnel0 3387 3388 3389 # on 4.3.2.1 3390 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3391 3392 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3393 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3394 3395``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3396 Configure VDE backend to connect to PORT n of a vde switch running 3397 on host and listening for incoming connections on socketpath. Use 3398 GROUP groupname and MODE octalmode to change default ownership and 3399 permissions for communication port. This option is only available if 3400 QEMU has been compiled with vde support enabled. 3401 3402 Example: 3403 3404 .. parsed-literal:: 3405 3406 # launch vde switch 3407 vde_switch -F -sock /tmp/myswitch 3408 # launch QEMU instance 3409 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3410 3411``-netdev af-xdp,id=str,ifname=name[,mode=native|skb][,force-copy=on|off][,queues=n][,start-queue=m][,inhibit=on|off][,sock-fds=x:y:...:z]`` 3412 Configure AF_XDP backend to connect to a network interface 'name' 3413 using AF_XDP socket. A specific program attach mode for a default 3414 XDP program can be forced with 'mode', defaults to best-effort, 3415 where the likely most performant mode will be in use. Number of queues 3416 'n' should generally match the number or queues in the interface, 3417 defaults to 1. Traffic arriving on non-configured device queues will 3418 not be delivered to the network backend. 3419 3420 .. parsed-literal:: 3421 3422 # set number of queues to 4 3423 ethtool -L eth0 combined 4 3424 # launch QEMU instance 3425 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3426 -netdev af-xdp,id=n1,ifname=eth0,queues=4 3427 3428 'start-queue' option can be specified if a particular range of queues 3429 [m, m + n] should be in use. For example, this is may be necessary in 3430 order to use certain NICs in native mode. Kernel allows the driver to 3431 create a separate set of XDP queues on top of regular ones, and only 3432 these queues can be used for AF_XDP sockets. NICs that work this way 3433 may also require an additional traffic redirection with ethtool to these 3434 special queues. 3435 3436 .. parsed-literal:: 3437 3438 # set number of queues to 1 3439 ethtool -L eth0 combined 1 3440 # redirect all the traffic to the second queue (id: 1) 3441 # note: drivers may require non-empty key/mask pair. 3442 ethtool -N eth0 flow-type ether \\ 3443 dst 00:00:00:00:00:00 m FF:FF:FF:FF:FF:FE action 1 3444 ethtool -N eth0 flow-type ether \\ 3445 dst 00:00:00:00:00:01 m FF:FF:FF:FF:FF:FE action 1 3446 # launch QEMU instance 3447 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3448 -netdev af-xdp,id=n1,ifname=eth0,queues=1,start-queue=1 3449 3450 XDP program can also be loaded externally. In this case 'inhibit' option 3451 should be set to 'on' and 'sock-fds' provided with file descriptors for 3452 already open but not bound XDP sockets already added to a socket map for 3453 corresponding queues. One socket per queue. 3454 3455 .. parsed-literal:: 3456 3457 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3458 -netdev af-xdp,id=n1,ifname=eth0,queues=3,inhibit=on,sock-fds=15:16:17 3459 3460``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3461 Establish a vhost-user netdev, backed by a chardev id. The chardev 3462 should be a unix domain socket backed one. The vhost-user uses a 3463 specifically defined protocol to pass vhost ioctl replacement 3464 messages to an application on the other end of the socket. On 3465 non-MSIX guests, the feature can be forced with vhostforce. Use 3466 'queues=n' to specify the number of queues to be created for 3467 multiqueue vhost-user. 3468 3469 Example: 3470 3471 :: 3472 3473 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3474 -numa node,memdev=mem \ 3475 -chardev socket,id=chr0,path=/path/to/socket \ 3476 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3477 -device virtio-net-pci,netdev=net0 3478 3479``-netdev vhost-vdpa[,vhostdev=/path/to/dev][,vhostfd=h]`` 3480 Establish a vhost-vdpa netdev. 3481 3482 vDPA device is a device that uses a datapath which complies with 3483 the virtio specifications with a vendor specific control path. 3484 vDPA devices can be both physically located on the hardware or 3485 emulated by software. 3486 3487``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3488 Create a hub port on the emulated hub with ID hubid. 3489 3490 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3491 instead of a single netdev. Alternatively, you can also connect the 3492 hubport to another netdev with ID nd by using the ``netdev=nd`` 3493 option. 3494 3495``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3496 Legacy option to configure or create an on-board (or machine 3497 default) Network Interface Card(NIC) and connect it either to the 3498 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3499 If model is omitted, then the default NIC model associated with the 3500 machine type is used. Note that the default NIC model may change in 3501 future QEMU releases, so it is highly recommended to always specify 3502 a model. Optionally, the MAC address can be changed to mac, the 3503 device address set to addr (PCI cards only), and a name can be 3504 assigned for use in monitor commands. Optionally, for PCI cards, you 3505 can specify the number v of MSI-X vectors that the card should have; 3506 this option currently only affects virtio cards; set v = 0 to 3507 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3508 created. QEMU can emulate several different models of network card. 3509 Use ``-net nic,model=help`` for a list of available devices for your 3510 target. 3511 3512``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3513 Configure a host network backend (with the options corresponding to 3514 the same ``-netdev`` option) and connect it to the emulated hub 0 3515 (the default hub). Use name to specify the name of the hub port. 3516ERST 3517 3518DEFHEADING() 3519 3520DEFHEADING(Character device options:) 3521 3522DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3523 "-chardev help\n" 3524 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3525 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3526 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3527 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3528 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3529 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3530 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3531 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3532 " [,logfile=PATH][,logappend=on|off]\n" 3533 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3534 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3535 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3536 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3537 "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3538 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3539#ifdef _WIN32 3540 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3541 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3542#else 3543 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3544 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3545#endif 3546#ifdef CONFIG_BRLAPI 3547 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3548#endif 3549#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3550 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3551 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3552#endif 3553#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3554 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3555#endif 3556#if defined(CONFIG_SPICE) 3557 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3558 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3559#endif 3560 , QEMU_ARCH_ALL 3561) 3562 3563SRST 3564The general form of a character device option is: 3565 3566``-chardev backend,id=id[,mux=on|off][,options]`` 3567 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3568 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3569 ``pty``, ``stdio``, ``braille``, ``parallel``, 3570 ``spicevmc``, ``spiceport``. The specific backend will determine the 3571 applicable options. 3572 3573 Use ``-chardev help`` to print all available chardev backend types. 3574 3575 All devices must have an id, which can be any string up to 127 3576 characters long. It is used to uniquely identify this device in 3577 other command line directives. 3578 3579 A character device may be used in multiplexing mode by multiple 3580 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3581 a "1:N" device, and here the "1" end is your specified chardev 3582 backend, and the "N" end is the various parts of QEMU that can talk 3583 to a chardev. If you create a chardev with ``id=myid`` and 3584 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3585 and you can then configure multiple front ends to use that chardev 3586 ID for their input/output. Up to four different front ends can be 3587 connected to a single multiplexed chardev. (Without multiplexing 3588 enabled, a chardev can only be used by a single front end.) For 3589 instance you could use this to allow a single stdio chardev to be 3590 used by two serial ports and the QEMU monitor: 3591 3592 :: 3593 3594 -chardev stdio,mux=on,id=char0 \ 3595 -mon chardev=char0,mode=readline \ 3596 -serial chardev:char0 \ 3597 -serial chardev:char0 3598 3599 You can have more than one multiplexer in a system configuration; 3600 for instance you could have a TCP port multiplexed between UART 0 3601 and UART 1, and stdio multiplexed between the QEMU monitor and a 3602 parallel port: 3603 3604 :: 3605 3606 -chardev stdio,mux=on,id=char0 \ 3607 -mon chardev=char0,mode=readline \ 3608 -parallel chardev:char0 \ 3609 -chardev tcp,...,mux=on,id=char1 \ 3610 -serial chardev:char1 \ 3611 -serial chardev:char1 3612 3613 When you're using a multiplexed character device, some escape 3614 sequences are interpreted in the input. See the chapter about 3615 :ref:`keys in the character backend multiplexer` in the 3616 System Emulation Users Guide for more details. 3617 3618 Note that some other command line options may implicitly create 3619 multiplexed character backends; for instance ``-serial mon:stdio`` 3620 creates a multiplexed stdio backend connected to the serial port and 3621 the QEMU monitor, and ``-nographic`` also multiplexes the console 3622 and the monitor to stdio. 3623 3624 There is currently no support for multiplexing in the other 3625 direction (where a single QEMU front end takes input and output from 3626 multiple chardevs). 3627 3628 Every backend supports the ``logfile`` option, which supplies the 3629 path to a file to record all data transmitted via the backend. The 3630 ``logappend`` option controls whether the log file will be truncated 3631 or appended to when opened. 3632 3633The available backends are: 3634 3635``-chardev null,id=id`` 3636 A void device. This device will not emit any data, and will drop any 3637 data it receives. The null backend does not take any options. 3638 3639``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3640 Create a two-way stream socket, which can be either a TCP or a unix 3641 socket. A unix socket will be created if ``path`` is specified. 3642 Behaviour is undefined if TCP options are specified for a unix 3643 socket. 3644 3645 ``server=on|off`` specifies that the socket shall be a listening socket. 3646 3647 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3648 to connect to a listening socket. 3649 3650 ``telnet=on|off`` specifies that traffic on the socket should interpret 3651 telnet escape sequences. 3652 3653 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3654 communication. 3655 3656 ``reconnect`` sets the timeout for reconnecting on non-server 3657 sockets when the remote end goes away. qemu will delay this many 3658 seconds and then attempt to reconnect. Zero disables reconnecting, 3659 and is the default. 3660 3661 ``tls-creds`` requests enablement of the TLS protocol for 3662 encryption, and specifies the id of the TLS credentials to use for 3663 the handshake. The credentials must be previously created with the 3664 ``-object tls-creds`` argument. 3665 3666 ``tls-auth`` provides the ID of the QAuthZ authorization object 3667 against which the client's x509 distinguished name will be 3668 validated. This object is only resolved at time of use, so can be 3669 deleted and recreated on the fly while the chardev server is active. 3670 If missing, it will default to denying access. 3671 3672 TCP and unix socket options are given below: 3673 3674 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3675 ``host`` for a listening socket specifies the local address to 3676 be bound. For a connecting socket species the remote host to 3677 connect to. ``host`` is optional for listening sockets. If not 3678 specified it defaults to ``0.0.0.0``. 3679 3680 ``port`` for a listening socket specifies the local port to be 3681 bound. For a connecting socket specifies the port on the remote 3682 host to connect to. ``port`` can be given as either a port 3683 number or a service name. ``port`` is required. 3684 3685 ``to`` is only relevant to listening sockets. If it is 3686 specified, and ``port`` cannot be bound, QEMU will attempt to 3687 bind to subsequent ports up to and including ``to`` until it 3688 succeeds. ``to`` must be specified as a port number. 3689 3690 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3691 or IPv6 must be used. If neither is specified the socket may 3692 use either protocol. 3693 3694 ``nodelay=on|off`` disables the Nagle algorithm. 3695 3696 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3697 ``path`` specifies the local path of the unix socket. ``path`` 3698 is required. 3699 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3700 rather than the filesystem. Optional, defaults to false. 3701 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3702 rather than the full sun_path length. Optional, defaults to true. 3703 3704``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3705 Sends all traffic from the guest to a remote host over UDP. 3706 3707 ``host`` specifies the remote host to connect to. If not specified 3708 it defaults to ``localhost``. 3709 3710 ``port`` specifies the port on the remote host to connect to. 3711 ``port`` is required. 3712 3713 ``localaddr`` specifies the local address to bind to. If not 3714 specified it defaults to ``0.0.0.0``. 3715 3716 ``localport`` specifies the local port to bind to. If not specified 3717 any available local port will be used. 3718 3719 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3720 If neither is specified the device may use either protocol. 3721 3722``-chardev msmouse,id=id`` 3723 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3724 does not take any options. 3725 3726``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3727 Connect to a QEMU text console. ``vc`` may optionally be given a 3728 specific size. 3729 3730 ``width`` and ``height`` specify the width and height respectively 3731 of the console, in pixels. 3732 3733 ``cols`` and ``rows`` specify that the console be sized to fit a 3734 text console with the given dimensions. 3735 3736``-chardev ringbuf,id=id[,size=size]`` 3737 Create a ring buffer with fixed size ``size``. size must be a power 3738 of two and defaults to ``64K``. 3739 3740``-chardev file,id=id,path=path[,input-path=input-path]`` 3741 Log all traffic received from the guest to a file. 3742 3743 ``path`` specifies the path of the file to be opened. This file will 3744 be created if it does not already exist, and overwritten if it does. 3745 ``path`` is required. 3746 3747 If ``input-path`` is specified, this is the path of a second file 3748 which will be used for input. If ``input-path`` is not specified, 3749 no input will be available from the chardev. 3750 3751 Note that ``input-path`` is not supported on Windows hosts. 3752 3753``-chardev pipe,id=id,path=path`` 3754 Create a two-way connection to the guest. The behaviour differs 3755 slightly between Windows hosts and other hosts: 3756 3757 On Windows, a single duplex pipe will be created at 3758 ``\\.pipe\path``. 3759 3760 On other hosts, 2 pipes will be created called ``path.in`` and 3761 ``path.out``. Data written to ``path.in`` will be received by the 3762 guest. Data written by the guest can be read from ``path.out``. QEMU 3763 will not create these fifos, and requires them to be present. 3764 3765 ``path`` forms part of the pipe path as described above. ``path`` is 3766 required. 3767 3768``-chardev console,id=id`` 3769 Send traffic from the guest to QEMU's standard output. ``console`` 3770 does not take any options. 3771 3772 ``console`` is only available on Windows hosts. 3773 3774``-chardev serial,id=id,path=path`` 3775 Send traffic from the guest to a serial device on the host. 3776 3777 On Unix hosts serial will actually accept any tty device, not only 3778 serial lines. 3779 3780 ``path`` specifies the name of the serial device to open. 3781 3782``-chardev pty,id=id`` 3783 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3784 does not take any options. 3785 3786 ``pty`` is not available on Windows hosts. 3787 3788``-chardev stdio,id=id[,signal=on|off]`` 3789 Connect to standard input and standard output of the QEMU process. 3790 3791 ``signal`` controls if signals are enabled on the terminal, that 3792 includes exiting QEMU with the key sequence Control-c. This option 3793 is enabled by default, use ``signal=off`` to disable it. 3794 3795``-chardev braille,id=id`` 3796 Connect to a local BrlAPI server. ``braille`` does not take any 3797 options. 3798 3799``-chardev parallel,id=id,path=path`` 3800 \ 3801 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3802 hosts. 3803 3804 Connect to a local parallel port. 3805 3806 ``path`` specifies the path to the parallel port device. ``path`` is 3807 required. 3808 3809``-chardev spicevmc,id=id,debug=debug,name=name`` 3810 ``spicevmc`` is only available when spice support is built in. 3811 3812 ``debug`` debug level for spicevmc 3813 3814 ``name`` name of spice channel to connect to 3815 3816 Connect to a spice virtual machine channel, such as vdiport. 3817 3818``-chardev spiceport,id=id,debug=debug,name=name`` 3819 ``spiceport`` is only available when spice support is built in. 3820 3821 ``debug`` debug level for spicevmc 3822 3823 ``name`` name of spice port to connect to 3824 3825 Connect to a spice port, allowing a Spice client to handle the 3826 traffic identified by a name (preferably a fqdn). 3827ERST 3828 3829DEFHEADING() 3830 3831#ifdef CONFIG_TPM 3832DEFHEADING(TPM device options:) 3833 3834DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3835 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3836 " use path to provide path to a character device; default is /dev/tpm0\n" 3837 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3838 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3839 "-tpmdev emulator,id=id,chardev=dev\n" 3840 " configure the TPM device using chardev backend\n", 3841 QEMU_ARCH_ALL) 3842SRST 3843The general form of a TPM device option is: 3844 3845``-tpmdev backend,id=id[,options]`` 3846 The specific backend type will determine the applicable options. The 3847 ``-tpmdev`` option creates the TPM backend and requires a 3848 ``-device`` option that specifies the TPM frontend interface model. 3849 3850 Use ``-tpmdev help`` to print all available TPM backend types. 3851 3852The available backends are: 3853 3854``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3855 (Linux-host only) Enable access to the host's TPM using the 3856 passthrough driver. 3857 3858 ``path`` specifies the path to the host's TPM device, i.e., on a 3859 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3860 default ``/dev/tpm0`` is used. 3861 3862 ``cancel-path`` specifies the path to the host TPM device's sysfs 3863 entry allowing for cancellation of an ongoing TPM command. 3864 ``cancel-path`` is optional and by default QEMU will search for the 3865 sysfs entry to use. 3866 3867 Some notes about using the host's TPM with the passthrough driver: 3868 3869 The TPM device accessed by the passthrough driver must not be used 3870 by any other application on the host. 3871 3872 Since the host's firmware (BIOS/UEFI) has already initialized the 3873 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3874 the TPM again and may therefore not show a TPM-specific menu that 3875 would otherwise allow the user to configure the TPM, e.g., allow the 3876 user to enable/disable or activate/deactivate the TPM. Further, if 3877 TPM ownership is released from within a VM then the host's TPM will 3878 get disabled and deactivated. To enable and activate the TPM again 3879 afterwards, the host has to be rebooted and the user is required to 3880 enter the firmware's menu to enable and activate the TPM. If the TPM 3881 is left disabled and/or deactivated most TPM commands will fail. 3882 3883 To create a passthrough TPM use the following two options: 3884 3885 :: 3886 3887 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3888 3889 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3890 ``tpmdev=tpm0`` in the device option. 3891 3892``-tpmdev emulator,id=id,chardev=dev`` 3893 (Linux-host only) Enable access to a TPM emulator using Unix domain 3894 socket based chardev backend. 3895 3896 ``chardev`` specifies the unique ID of a character device backend 3897 that provides connection to the software TPM server. 3898 3899 To create a TPM emulator backend device with chardev socket backend: 3900 3901 :: 3902 3903 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3904ERST 3905 3906DEFHEADING() 3907 3908#endif 3909 3910DEFHEADING(Boot Image or Kernel specific:) 3911SRST 3912There are broadly 4 ways you can boot a system with QEMU. 3913 3914 - specify a firmware and let it control finding a kernel 3915 - specify a firmware and pass a hint to the kernel to boot 3916 - direct kernel image boot 3917 - manually load files into the guest's address space 3918 3919The third method is useful for quickly testing kernels but as there is 3920no firmware to pass configuration information to the kernel the 3921hardware must either be probeable, the kernel built for the exact 3922configuration or passed some configuration data (e.g. a DTB blob) 3923which tells the kernel what drivers it needs. This exact details are 3924often hardware specific. 3925 3926The final method is the most generic way of loading images into the 3927guest address space and used mostly for ``bare metal`` type 3928development where the reset vectors of the processor are taken into 3929account. 3930 3931ERST 3932 3933SRST 3934 3935For x86 machines and some other architectures ``-bios`` will generally 3936do the right thing with whatever it is given. For other machines the 3937more strict ``-pflash`` option needs an image that is sized for the 3938flash device for the given machine type. 3939 3940Please see the :ref:`system-targets-ref` section of the manual for 3941more detailed documentation. 3942 3943ERST 3944 3945DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3946 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3947SRST 3948``-bios file`` 3949 Set the filename for the BIOS. 3950ERST 3951 3952DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3953 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3954SRST 3955``-pflash file`` 3956 Use file as a parallel flash image. 3957ERST 3958 3959SRST 3960 3961The kernel options were designed to work with Linux kernels although 3962other things (like hypervisors) can be packaged up as a kernel 3963executable image. The exact format of a executable image is usually 3964architecture specific. 3965 3966The way in which the kernel is started (what address it is loaded at, 3967what if any information is passed to it via CPU registers, the state 3968of the hardware when it is started, and so on) is also architecture 3969specific. Typically it follows the specification laid down by the 3970Linux kernel for how kernels for that architecture must be started. 3971 3972ERST 3973 3974DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3975 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3976SRST 3977``-kernel bzImage`` 3978 Use bzImage as kernel image. The kernel can be either a Linux kernel 3979 or in multiboot format. 3980ERST 3981 3982DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3983 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3984SRST 3985``-append cmdline`` 3986 Use cmdline as kernel command line 3987ERST 3988 3989DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3990 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3991SRST 3992 3993``-initrd file`` 3994 Use file as initial ram disk. 3995 3996``-initrd "file1 arg=foo,file2"`` 3997 This syntax is only available with multiboot. 3998 3999 Use file1 and file2 as modules and pass ``arg=foo`` as parameter to the 4000 first module. Commas can be provided in module parameters by doubling 4001 them on the command line to escape them: 4002 4003``-initrd "bzImage earlyprintk=xen,,keep root=/dev/xvda1,initrd.img"`` 4004 Multiboot only. Use bzImage as the first module with 4005 "``earlyprintk=xen,keep root=/dev/xvda1``" as its command line, 4006 and initrd.img as the second module. 4007 4008ERST 4009 4010DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 4011 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 4012SRST 4013``-dtb file`` 4014 Use file as a device tree binary (dtb) image and pass it to the 4015 kernel on boot. 4016ERST 4017 4018SRST 4019 4020Finally you can also manually load images directly into the address 4021space of the guest. This is most useful for developers who already 4022know the layout of their guest and take care to ensure something sane 4023will happen when the reset vector executes. 4024 4025The generic loader can be invoked by using the loader device: 4026 4027``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 4028 4029there is also the guest loader which operates in a similar way but 4030tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 4031the guest image is: 4032 4033``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 4034 4035ERST 4036 4037DEFHEADING() 4038 4039DEFHEADING(Debug/Expert options:) 4040 4041DEF("compat", HAS_ARG, QEMU_OPTION_compat, 4042 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 4043 " Policy for handling deprecated management interfaces\n" 4044 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 4045 " Policy for handling unstable management interfaces\n", 4046 QEMU_ARCH_ALL) 4047SRST 4048``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 4049 Set policy for handling deprecated management interfaces (experimental): 4050 4051 ``deprecated-input=accept`` (default) 4052 Accept deprecated commands and arguments 4053 ``deprecated-input=reject`` 4054 Reject deprecated commands and arguments 4055 ``deprecated-input=crash`` 4056 Crash on deprecated commands and arguments 4057 ``deprecated-output=accept`` (default) 4058 Emit deprecated command results and events 4059 ``deprecated-output=hide`` 4060 Suppress deprecated command results and events 4061 4062 Limitation: covers only syntactic aspects of QMP. 4063 4064``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 4065 Set policy for handling unstable management interfaces (experimental): 4066 4067 ``unstable-input=accept`` (default) 4068 Accept unstable commands and arguments 4069 ``unstable-input=reject`` 4070 Reject unstable commands and arguments 4071 ``unstable-input=crash`` 4072 Crash on unstable commands and arguments 4073 ``unstable-output=accept`` (default) 4074 Emit unstable command results and events 4075 ``unstable-output=hide`` 4076 Suppress unstable command results and events 4077 4078 Limitation: covers only syntactic aspects of QMP. 4079ERST 4080 4081DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 4082 "-fw_cfg [name=]<name>,file=<file>\n" 4083 " add named fw_cfg entry with contents from file\n" 4084 "-fw_cfg [name=]<name>,string=<str>\n" 4085 " add named fw_cfg entry with contents from string\n", 4086 QEMU_ARCH_ALL) 4087SRST 4088``-fw_cfg [name=]name,file=file`` 4089 Add named fw\_cfg entry with contents from file file. 4090 If the filename contains comma, you must double it (for instance, 4091 "file=my,,file" to use file "my,file"). 4092 4093``-fw_cfg [name=]name,string=str`` 4094 Add named fw\_cfg entry with contents from string str. 4095 If the string contains comma, you must double it (for instance, 4096 "string=my,,string" to use file "my,string"). 4097 4098 The terminating NUL character of the contents of str will not be 4099 included as part of the fw\_cfg item data. To insert contents with 4100 embedded NUL characters, you have to use the file parameter. 4101 4102 The fw\_cfg entries are passed by QEMU through to the guest. 4103 4104 Example: 4105 4106 :: 4107 4108 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 4109 4110 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 4111 from ./my\_blob.bin. 4112ERST 4113 4114DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 4115 "-serial dev redirect the serial port to char device 'dev'\n", 4116 QEMU_ARCH_ALL) 4117SRST 4118``-serial dev`` 4119 Redirect the virtual serial port to host character device dev. The 4120 default device is ``vc`` in graphical mode and ``stdio`` in non 4121 graphical mode. 4122 4123 This option can be used several times to simulate up to 4 serial 4124 ports. 4125 4126 Use ``-serial none`` to disable all serial ports. 4127 4128 Available character devices are: 4129 4130 ``vc[:WxH]`` 4131 Virtual console. Optionally, a width and height can be given in 4132 pixel with 4133 4134 :: 4135 4136 vc:800x600 4137 4138 It is also possible to specify width or height in characters: 4139 4140 :: 4141 4142 vc:80Cx24C 4143 4144 ``pty`` 4145 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 4146 4147 ``none`` 4148 No device is allocated. 4149 4150 ``null`` 4151 void device 4152 4153 ``chardev:id`` 4154 Use a named character device defined with the ``-chardev`` 4155 option. 4156 4157 ``/dev/XXX`` 4158 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 4159 port parameters are set according to the emulated ones. 4160 4161 ``/dev/parportN`` 4162 [Linux only, parallel port only] Use host parallel port N. 4163 Currently SPP and EPP parallel port features can be used. 4164 4165 ``file:filename`` 4166 Write output to filename. No character can be read. 4167 4168 ``stdio`` 4169 [Unix only] standard input/output 4170 4171 ``pipe:filename`` 4172 name pipe filename 4173 4174 ``COMn`` 4175 [Windows only] Use host serial port n 4176 4177 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 4178 This implements UDP Net Console. When remote\_host or src\_ip 4179 are not specified they default to ``0.0.0.0``. When not using a 4180 specified src\_port a random port is automatically chosen. 4181 4182 If you just want a simple readonly console you can use 4183 ``netcat`` or ``nc``, by starting QEMU with: 4184 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 4185 QEMU writes something to that port it will appear in the 4186 netconsole session. 4187 4188 If you plan to send characters back via netconsole or you want 4189 to stop and start QEMU a lot of times, you should have QEMU use 4190 the same source port each time by using something like ``-serial 4191 udp::4555@:4556`` to QEMU. Another approach is to use a patched 4192 version of netcat which can listen to a TCP port and send and 4193 receive characters via udp. If you have a patched version of 4194 netcat which activates telnet remote echo and single char 4195 transfer, then you can use the following options to set up a 4196 netcat redirector to allow telnet on port 5555 to access the 4197 QEMU port. 4198 4199 ``QEMU Options:`` 4200 -serial udp::4555@:4556 4201 4202 ``netcat options:`` 4203 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 4204 4205 ``telnet options:`` 4206 localhost 5555 4207 4208 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4209 The TCP Net Console has two modes of operation. It can send the 4210 serial I/O to a location or wait for a connection from a 4211 location. By default the TCP Net Console is sent to host at the 4212 port. If you use the ``server=on`` option QEMU will wait for a client 4213 socket application to connect to the port before continuing, 4214 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4215 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4216 option only applies if ``server=no`` is set, if the connection goes 4217 down it will attempt to reconnect at the given interval. If host 4218 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4219 time is accepted. You can use ``telnet=on`` to connect to the 4220 corresponding character device. 4221 4222 ``Example to send tcp console to 192.168.0.2 port 4444`` 4223 -serial tcp:192.168.0.2:4444 4224 4225 ``Example to listen and wait on port 4444 for connection`` 4226 -serial tcp::4444,server=on 4227 4228 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4229 -serial tcp:192.168.0.100:4444,server=on,wait=off 4230 4231 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4232 The telnet protocol is used instead of raw tcp sockets. The 4233 options work the same as if you had specified ``-serial tcp``. 4234 The difference is that the port acts like a telnet server or 4235 client using telnet option negotiation. This will also allow you 4236 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4237 supports sending the break sequence. Typically in unix telnet 4238 you do it with Control-] and then type "send break" followed by 4239 pressing the enter key. 4240 4241 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4242 The WebSocket protocol is used instead of raw tcp socket. The 4243 port acts as a WebSocket server. Client mode is not supported. 4244 4245 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4246 A unix domain socket is used instead of a tcp socket. The option 4247 works the same as if you had specified ``-serial tcp`` except 4248 the unix domain socket path is used for connections. 4249 4250 ``mon:dev_string`` 4251 This is a special option to allow the monitor to be multiplexed 4252 onto another serial port. The monitor is accessed with key 4253 sequence of Control-a and then pressing c. dev\_string should be 4254 any one of the serial devices specified above. An example to 4255 multiplex the monitor onto a telnet server listening on port 4256 4444 would be: 4257 4258 ``-serial mon:telnet::4444,server=on,wait=off`` 4259 4260 When the monitor is multiplexed to stdio in this way, Ctrl+C 4261 will not terminate QEMU any more but will be passed to the guest 4262 instead. 4263 4264 ``braille`` 4265 Braille device. This will use BrlAPI to display the braille 4266 output on a real or fake device. 4267 4268 ``msmouse`` 4269 Three button serial mouse. Configure the guest to use Microsoft 4270 protocol. 4271ERST 4272 4273DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4274 "-parallel dev redirect the parallel port to char device 'dev'\n", 4275 QEMU_ARCH_ALL) 4276SRST 4277``-parallel dev`` 4278 Redirect the virtual parallel port to host device dev (same devices 4279 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4280 to use hardware devices connected on the corresponding host parallel 4281 port. 4282 4283 This option can be used several times to simulate up to 3 parallel 4284 ports. 4285 4286 Use ``-parallel none`` to disable all parallel ports. 4287ERST 4288 4289DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4290 "-monitor dev redirect the monitor to char device 'dev'\n", 4291 QEMU_ARCH_ALL) 4292SRST 4293``-monitor dev`` 4294 Redirect the monitor to host device dev (same devices as the serial 4295 port). The default device is ``vc`` in graphical mode and ``stdio`` 4296 in non graphical mode. Use ``-monitor none`` to disable the default 4297 monitor. 4298ERST 4299DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4300 "-qmp dev like -monitor but opens in 'control' mode\n", 4301 QEMU_ARCH_ALL) 4302SRST 4303``-qmp dev`` 4304 Like ``-monitor`` but opens in 'control' mode. For example, to make 4305 QMP available on localhost port 4444:: 4306 4307 -qmp tcp:localhost:4444,server=on,wait=off 4308 4309 Not all options are configurable via this syntax; for maximum 4310 flexibility use the ``-mon`` option and an accompanying ``-chardev``. 4311 4312ERST 4313DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4314 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4315 QEMU_ARCH_ALL) 4316SRST 4317``-qmp-pretty dev`` 4318 Like ``-qmp`` but uses pretty JSON formatting. 4319ERST 4320 4321DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4322 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4323SRST 4324``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4325 Set up a monitor connected to the chardev ``name``. 4326 QEMU supports two monitors: the Human Monitor Protocol 4327 (HMP; for human interaction), and the QEMU Monitor Protocol 4328 (QMP; a JSON RPC-style protocol). 4329 The default is HMP; ``mode=control`` selects QMP instead. 4330 ``pretty`` is only valid when ``mode=control``, 4331 turning on JSON pretty printing to ease 4332 human reading and debugging. 4333 4334 For example:: 4335 4336 -chardev socket,id=mon1,host=localhost,port=4444,server=on,wait=off \ 4337 -mon chardev=mon1,mode=control,pretty=on 4338 4339 enables the QMP monitor on localhost port 4444 with pretty-printing. 4340ERST 4341 4342DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4343 "-debugcon dev redirect the debug console to char device 'dev'\n", 4344 QEMU_ARCH_ALL) 4345SRST 4346``-debugcon dev`` 4347 Redirect the debug console to host device dev (same devices as the 4348 serial port). The debug console is an I/O port which is typically 4349 port 0xe9; writing to that I/O port sends output to this device. The 4350 default device is ``vc`` in graphical mode and ``stdio`` in non 4351 graphical mode. 4352ERST 4353 4354DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4355 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4356SRST 4357``-pidfile file`` 4358 Store the QEMU process PID in file. It is useful if you launch QEMU 4359 from a script. 4360ERST 4361 4362DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4363 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4364 QEMU_ARCH_ALL) 4365SRST 4366``--preconfig`` 4367 Pause QEMU for interactive configuration before the machine is 4368 created, which allows querying and configuring properties that will 4369 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4370 exit the preconfig state and move to the next state (i.e. run guest 4371 if -S isn't used or pause the second time if -S is used). This 4372 option is experimental. 4373ERST 4374 4375DEF("S", 0, QEMU_OPTION_S, \ 4376 "-S freeze CPU at startup (use 'c' to start execution)\n", 4377 QEMU_ARCH_ALL) 4378SRST 4379``-S`` 4380 Do not start CPU at startup (you must type 'c' in the monitor). 4381ERST 4382 4383DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4384 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4385 " run qemu with overcommit hints\n" 4386 " mem-lock=on|off controls memory lock support (default: off)\n" 4387 " cpu-pm=on|off controls cpu power management (default: off)\n", 4388 QEMU_ARCH_ALL) 4389SRST 4390``-overcommit mem-lock=on|off`` 4391 \ 4392``-overcommit cpu-pm=on|off`` 4393 Run qemu with hints about host resource overcommit. The default is 4394 to assume that host overcommits all resources. 4395 4396 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4397 (disabled by default). This works when host memory is not 4398 overcommitted and reduces the worst-case latency for guest. 4399 4400 Guest ability to manage power state of host cpus (increasing latency 4401 for other processes on the same host cpu, but decreasing latency for 4402 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4403 works best when host CPU is not overcommitted. When used, host 4404 estimates of CPU cycle and power utilization will be incorrect, not 4405 taking into account guest idle time. 4406ERST 4407 4408DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4409 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4410 " the guest without waiting for gdb to connect; use -S too\n" 4411 " if you want it to not start execution.)\n", 4412 QEMU_ARCH_ALL) 4413SRST 4414``-gdb dev`` 4415 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4416 in the System Emulation Users Guide). Note that this option does not pause QEMU 4417 execution -- if you want QEMU to not start the guest until you 4418 connect with gdb and issue a ``continue`` command, you will need to 4419 also pass the ``-S`` option to QEMU. 4420 4421 The most usual configuration is to listen on a local TCP socket:: 4422 4423 -gdb tcp::3117 4424 4425 but you can specify other backends; UDP, pseudo TTY, or even stdio 4426 are all reasonable use cases. For example, a stdio connection 4427 allows you to start QEMU from within gdb and establish the 4428 connection via a pipe: 4429 4430 .. parsed-literal:: 4431 4432 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4433ERST 4434 4435DEF("s", 0, QEMU_OPTION_s, \ 4436 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4437 QEMU_ARCH_ALL) 4438SRST 4439``-s`` 4440 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4441 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4442ERST 4443 4444DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4445 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4446 QEMU_ARCH_ALL) 4447SRST 4448``-d item1[,...]`` 4449 Enable logging of specified items. Use '-d help' for a list of log 4450 items. 4451ERST 4452 4453DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4454 "-D logfile output log to logfile (default stderr)\n", 4455 QEMU_ARCH_ALL) 4456SRST 4457``-D logfile`` 4458 Output log in logfile instead of to stderr 4459ERST 4460 4461DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4462 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4463 QEMU_ARCH_ALL) 4464SRST 4465``-dfilter range1[,...]`` 4466 Filter debug output to that relevant to a range of target addresses. 4467 The filter spec can be either start+size, start-size or start..end 4468 where start end and size are the addresses and sizes required. For 4469 example: 4470 4471 :: 4472 4473 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4474 4475 Will dump output for any code in the 0x1000 sized block starting at 4476 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4477 another 0x1000 sized block starting at 0xffffffc00005f000. 4478ERST 4479 4480DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4481 "-seed number seed the pseudo-random number generator\n", 4482 QEMU_ARCH_ALL) 4483SRST 4484``-seed number`` 4485 Force the guest to use a deterministic pseudo-random number 4486 generator, seeded with number. This does not affect crypto routines 4487 within the host. 4488ERST 4489 4490DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4491 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4492 QEMU_ARCH_ALL) 4493SRST 4494``-L path`` 4495 Set the directory for the BIOS, VGA BIOS and keymaps. 4496 4497 To list all the data directories, use ``-L help``. 4498ERST 4499 4500DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4501 "-enable-kvm enable KVM full virtualization support\n", 4502 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4503 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4504SRST 4505``-enable-kvm`` 4506 Enable KVM full virtualization support. This option is only 4507 available if KVM support is enabled when compiling. 4508ERST 4509 4510DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4511 "-xen-domid id specify xen guest domain id\n", 4512 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4513DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4514 "-xen-attach attach to existing xen domain\n" 4515 " libxl will use this when starting QEMU\n", 4516 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4517DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4518 "-xen-domid-restrict restrict set of available xen operations\n" 4519 " to specified domain id. (Does not affect\n" 4520 " xenpv machine type).\n", 4521 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4522SRST 4523``-xen-domid id`` 4524 Specify xen guest domain id (XEN only). 4525 4526``-xen-attach`` 4527 Attach to existing xen domain. libxl will use this when starting 4528 QEMU (XEN only). Restrict set of available xen operations to 4529 specified domain id (XEN only). 4530ERST 4531 4532DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4533 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4534SRST 4535``-no-reboot`` 4536 Exit instead of rebooting. 4537ERST 4538 4539DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4540 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4541SRST 4542``-no-shutdown`` 4543 Don't exit QEMU on guest shutdown, but instead only stop the 4544 emulation. This allows for instance switching to monitor to commit 4545 changes to the disk image. 4546ERST 4547 4548DEF("action", HAS_ARG, QEMU_OPTION_action, 4549 "-action reboot=reset|shutdown\n" 4550 " action when guest reboots [default=reset]\n" 4551 "-action shutdown=poweroff|pause\n" 4552 " action when guest shuts down [default=poweroff]\n" 4553 "-action panic=pause|shutdown|exit-failure|none\n" 4554 " action when guest panics [default=shutdown]\n" 4555 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4556 " action when watchdog fires [default=reset]\n", 4557 QEMU_ARCH_ALL) 4558SRST 4559``-action event=action`` 4560 The action parameter serves to modify QEMU's default behavior when 4561 certain guest events occur. It provides a generic method for specifying the 4562 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4563 parameters. 4564 4565 Examples: 4566 4567 ``-action panic=none`` 4568 ``-action reboot=shutdown,shutdown=pause`` 4569 ``-device i6300esb -action watchdog=pause`` 4570 4571ERST 4572 4573DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4574 "-loadvm [tag|id]\n" \ 4575 " start right away with a saved state (loadvm in monitor)\n", 4576 QEMU_ARCH_ALL) 4577SRST 4578``-loadvm file`` 4579 Start right away with a saved state (``loadvm`` in monitor) 4580ERST 4581 4582#ifndef _WIN32 4583DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4584 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4585#endif 4586SRST 4587``-daemonize`` 4588 Daemonize the QEMU process after initialization. QEMU will not 4589 detach from standard IO until it is ready to receive connections on 4590 any of its devices. This option is a useful way for external 4591 programs to launch QEMU without having to cope with initialization 4592 race conditions. 4593ERST 4594 4595DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4596 "-option-rom rom load a file, rom, into the option ROM space\n", 4597 QEMU_ARCH_ALL) 4598SRST 4599``-option-rom file`` 4600 Load the contents of file as an option ROM. This option is useful to 4601 load things like EtherBoot. 4602ERST 4603 4604DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4605 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4606 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4607 QEMU_ARCH_ALL) 4608 4609SRST 4610``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4611 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4612 the current UTC or local time, respectively. ``localtime`` is 4613 required for correct date in MS-DOS or Windows. To start at a 4614 specific point in time, provide datetime in the format 4615 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4616 4617 By default the RTC is driven by the host system time. This allows 4618 using of the RTC as accurate reference clock inside the guest, 4619 specifically if the host time is smoothly following an accurate 4620 external reference clock, e.g. via NTP. If you want to isolate the 4621 guest time from the host, you can set ``clock`` to ``rt`` instead, 4622 which provides a host monotonic clock if host support it. To even 4623 prevent the RTC from progressing during suspension, you can set 4624 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4625 recommended especially in icount mode in order to preserve 4626 determinism; however, note that in icount mode the speed of the 4627 virtual clock is variable and can in general differ from the host 4628 clock. 4629 4630 Enable ``driftfix`` (i386 targets only) if you experience time drift 4631 problems, specifically with Windows' ACPI HAL. This option will try 4632 to figure out how many timer interrupts were not processed by the 4633 Windows guest and will re-inject them. 4634ERST 4635 4636DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4637 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4638 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4639 " instruction, enable aligning the host and virtual clocks\n" \ 4640 " or disable real time cpu sleeping, and optionally enable\n" \ 4641 " record-and-replay mode\n", QEMU_ARCH_ALL) 4642SRST 4643``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4644 Enable virtual instruction counter. The virtual cpu will execute one 4645 instruction every 2^N ns of virtual time. If ``auto`` is specified 4646 then the virtual cpu speed will be automatically adjusted to keep 4647 virtual time within a few seconds of real time. 4648 4649 Note that while this option can give deterministic behavior, it does 4650 not provide cycle accurate emulation. Modern CPUs contain 4651 superscalar out of order cores with complex cache hierarchies. The 4652 number of instructions executed often has little or no correlation 4653 with actual performance. 4654 4655 When the virtual cpu is sleeping, the virtual time will advance at 4656 default speed unless ``sleep=on`` is specified. With 4657 ``sleep=on``, the virtual time will jump to the next timer 4658 deadline instantly whenever the virtual cpu goes to sleep mode and 4659 will not advance if no timer is enabled. This behavior gives 4660 deterministic execution times from the guest point of view. 4661 The default if icount is enabled is ``sleep=off``. 4662 ``sleep=on`` cannot be used together with either ``shift=auto`` 4663 or ``align=on``. 4664 4665 ``align=on`` will activate the delay algorithm which will try to 4666 synchronise the host clock and the virtual clock. The goal is to 4667 have a guest running at the real frequency imposed by the shift 4668 option. Whenever the guest clock is behind the host clock and if 4669 ``align=on`` is specified then we print a message to the user to 4670 inform about the delay. Currently this option does not work when 4671 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4672 shift values for which the guest clock runs ahead of the host clock. 4673 Typically this happens when the shift value is high (how high 4674 depends on the host machine). The default if icount is enabled 4675 is ``align=off``. 4676 4677 When the ``rr`` option is specified deterministic record/replay is 4678 enabled. The ``rrfile=`` option must also be provided to 4679 specify the path to the replay log. In record mode data is written 4680 to this file, and in replay mode it is read back. 4681 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4682 name. In record mode, a new VM snapshot with the given name is created 4683 at the start of execution recording. In replay mode this option 4684 specifies the snapshot name used to load the initial VM state. 4685ERST 4686 4687DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4688 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4689 " action when watchdog fires [default=reset]\n", 4690 QEMU_ARCH_ALL) 4691SRST 4692``-watchdog-action action`` 4693 The action controls what QEMU will do when the watchdog timer 4694 expires. The default is ``reset`` (forcefully reset the guest). 4695 Other possible actions are: ``shutdown`` (attempt to gracefully 4696 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4697 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4698 guest), ``debug`` (print a debug message and continue), or ``none`` 4699 (do nothing). 4700 4701 Note that the ``shutdown`` action requires that the guest responds 4702 to ACPI signals, which it may not be able to do in the sort of 4703 situations where the watchdog would have expired, and thus 4704 ``-watchdog-action shutdown`` is not recommended for production use. 4705 4706 Examples: 4707 4708 ``-device i6300esb -watchdog-action pause`` 4709 4710ERST 4711 4712DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4713 "-echr chr set terminal escape character instead of ctrl-a\n", 4714 QEMU_ARCH_ALL) 4715SRST 4716``-echr numeric_ascii_value`` 4717 Change the escape character used for switching to the monitor when 4718 using monitor and serial sharing. The default is ``0x01`` when using 4719 the ``-nographic`` option. ``0x01`` is equal to pressing 4720 ``Control-a``. You can select a different character from the ascii 4721 control keys where 1 through 26 map to Control-a through Control-z. 4722 For instance you could use the either of the following to change the 4723 escape character to Control-t. 4724 4725 ``-echr 0x14``; \ ``-echr 20`` 4726 4727ERST 4728 4729DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4730 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4731 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4732 "-incoming unix:socketpath\n" \ 4733 " prepare for incoming migration, listen on\n" \ 4734 " specified protocol and socket address\n" \ 4735 "-incoming fd:fd\n" \ 4736 "-incoming file:filename[,offset=offset]\n" \ 4737 "-incoming exec:cmdline\n" \ 4738 " accept incoming migration on given file descriptor\n" \ 4739 " or from given external command\n" \ 4740 "-incoming defer\n" \ 4741 " wait for the URI to be specified via migrate_incoming\n", 4742 QEMU_ARCH_ALL) 4743SRST 4744``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4745 \ 4746``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4747 Prepare for incoming migration, listen on a given tcp port. 4748 4749``-incoming unix:socketpath`` 4750 Prepare for incoming migration, listen on a given unix socket. 4751 4752``-incoming fd:fd`` 4753 Accept incoming migration from a given file descriptor. 4754 4755``-incoming file:filename[,offset=offset]`` 4756 Accept incoming migration from a given file starting at offset. 4757 offset allows the common size suffixes, or a 0x prefix, but not both. 4758 4759``-incoming exec:cmdline`` 4760 Accept incoming migration as an output from specified external 4761 command. 4762 4763``-incoming defer`` 4764 Wait for the URI to be specified via migrate\_incoming. The monitor 4765 can be used to change settings (such as migration parameters) prior 4766 to issuing the migrate\_incoming to allow the migration to begin. 4767ERST 4768 4769DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4770 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4771SRST 4772``-only-migratable`` 4773 Only allow migratable devices. Devices will not be allowed to enter 4774 an unmigratable state. 4775ERST 4776 4777DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4778 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4779SRST 4780``-nodefaults`` 4781 Don't create default devices. Normally, QEMU sets the default 4782 devices like serial port, parallel port, virtual console, monitor 4783 device, VGA adapter, floppy and CD-ROM drive and others. The 4784 ``-nodefaults`` option will disable all those default devices. 4785ERST 4786 4787#ifndef _WIN32 4788DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4789 "-runas user change to user id user just before starting the VM\n" \ 4790 " user can be numeric uid:gid instead\n", 4791 QEMU_ARCH_ALL) 4792#endif 4793SRST 4794``-runas user`` 4795 Immediately before starting guest execution, drop root privileges, 4796 switching to the specified user. 4797ERST 4798 4799DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4800 "-prom-env variable=value\n" 4801 " set OpenBIOS nvram variables\n", 4802 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4803SRST 4804``-prom-env variable=value`` 4805 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4806 4807 :: 4808 4809 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4810 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4811 4812 :: 4813 4814 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4815 -prom-env 'boot-device=hd:2,\yaboot' \ 4816 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4817ERST 4818DEF("semihosting", 0, QEMU_OPTION_semihosting, 4819 "-semihosting semihosting mode\n", 4820 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4821 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4822SRST 4823``-semihosting`` 4824 Enable :ref:`Semihosting` mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4825 4826 .. warning:: 4827 Note that this allows guest direct access to the host filesystem, so 4828 should only be used with a trusted guest OS. 4829 4830 See the -semihosting-config option documentation for further 4831 information about the facilities this enables. 4832ERST 4833DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4834 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4835 " semihosting configuration\n", 4836QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4837QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4838SRST 4839``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4840 Enable and configure :ref:`Semihosting` (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4841 only). 4842 4843 .. warning:: 4844 Note that this allows guest direct access to the host filesystem, so 4845 should only be used with a trusted guest OS. 4846 4847 ``target=native|gdb|auto`` 4848 Defines where the semihosting calls will be addressed, to QEMU 4849 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4850 means ``gdb`` during debug sessions and ``native`` otherwise. 4851 4852 ``chardev=str1`` 4853 Send the output to a chardev backend output for native or auto 4854 output when not in gdb 4855 4856 ``userspace=on|off`` 4857 Allows code running in guest userspace to access the semihosting 4858 interface. The default is that only privileged guest code can 4859 make semihosting calls. Note that setting ``userspace=on`` should 4860 only be used if all guest code is trusted (for example, in 4861 bare-metal test case code). 4862 4863 ``arg=str1,arg=str2,...`` 4864 Allows the user to pass input arguments, and can be used 4865 multiple times to build up a list. The old-style 4866 ``-kernel``/``-append`` method of passing a command line is 4867 still supported for backward compatibility. If both the 4868 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4869 specified, the former is passed to semihosting as it always 4870 takes precedence. 4871ERST 4872DEF("old-param", 0, QEMU_OPTION_old_param, 4873 "-old-param old param mode\n", QEMU_ARCH_ARM) 4874SRST 4875``-old-param`` 4876 Old param mode (ARM only). 4877ERST 4878 4879DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4880 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4881 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4882 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4883 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4884 " by the kernel, but typically no longer used by modern\n" \ 4885 " C library implementations.\n" \ 4886 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4887 " to elevate privileges using set*uid|gid system calls.\n" \ 4888 " The value 'children' will deny set*uid|gid system calls for\n" \ 4889 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4890 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4891 " blocking *fork and execve\n" \ 4892 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4893 QEMU_ARCH_ALL) 4894SRST 4895``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4896 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4897 filtering and 'off' will disable it. The default is 'off'. 4898 4899 ``obsolete=string`` 4900 Enable Obsolete system calls 4901 4902 ``elevateprivileges=string`` 4903 Disable set\*uid\|gid system calls 4904 4905 ``spawn=string`` 4906 Disable \*fork and execve 4907 4908 ``resourcecontrol=string`` 4909 Disable process affinity and schedular priority 4910ERST 4911 4912DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4913 "-readconfig <file>\n" 4914 " read config file\n", QEMU_ARCH_ALL) 4915SRST 4916``-readconfig file`` 4917 Read device configuration from file. This approach is useful when 4918 you want to spawn QEMU process with many command line options but 4919 you don't want to exceed the command line character limit. 4920ERST 4921 4922DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4923 "-no-user-config\n" 4924 " do not load default user-provided config files at startup\n", 4925 QEMU_ARCH_ALL) 4926SRST 4927``-no-user-config`` 4928 The ``-no-user-config`` option makes QEMU not load any of the 4929 user-provided config files on sysconfdir. 4930ERST 4931 4932DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4933 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4934 " specify tracing options\n", 4935 QEMU_ARCH_ALL) 4936SRST 4937``-trace [[enable=]pattern][,events=file][,file=file]`` 4938 .. include:: ../qemu-option-trace.rst.inc 4939 4940ERST 4941DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4942 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4943 " load a plugin\n", 4944 QEMU_ARCH_ALL) 4945SRST 4946``-plugin file=file[,argname=argvalue]`` 4947 Load a plugin. 4948 4949 ``file=file`` 4950 Load the given plugin from a shared library file. 4951 4952 ``argname=argvalue`` 4953 Argument passed to the plugin. (Can be given multiple times.) 4954ERST 4955 4956HXCOMM Internal use 4957DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4958DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4959 4960#ifdef CONFIG_POSIX 4961DEF("run-with", HAS_ARG, QEMU_OPTION_run_with, 4962 "-run-with [async-teardown=on|off][,chroot=dir]\n" 4963 " Set miscellaneous QEMU process lifecycle options:\n" 4964 " async-teardown=on enables asynchronous teardown (Linux only)\n" 4965 " chroot=dir chroot to dir just before starting the VM\n", 4966 QEMU_ARCH_ALL) 4967SRST 4968``-run-with [async-teardown=on|off][,chroot=dir]`` 4969 Set QEMU process lifecycle options. 4970 4971 ``async-teardown=on`` enables asynchronous teardown. A new process called 4972 "cleanup/<QEMU_PID>" will be created at startup sharing the address 4973 space with the main QEMU process, using clone. It will wait for the 4974 main QEMU process to terminate completely, and then exit. This allows 4975 QEMU to terminate very quickly even if the guest was huge, leaving the 4976 teardown of the address space to the cleanup process. Since the cleanup 4977 process shares the same cgroups as the main QEMU process, accounting is 4978 performed correctly. This only works if the cleanup process is not 4979 forcefully killed with SIGKILL before the main QEMU process has 4980 terminated completely. 4981 4982 ``chroot=dir`` can be used for doing a chroot to the specified directory 4983 immediately before starting the guest execution. This is especially useful 4984 in combination with -runas. 4985ERST 4986#endif 4987 4988DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4989 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4990 " control error message format\n" 4991 " timestamp=on enables timestamps (default: off)\n" 4992 " guest-name=on enables guest name prefix but only if\n" 4993 " -name guest option is set (default: off)\n", 4994 QEMU_ARCH_ALL) 4995SRST 4996``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4997 Control error message format. 4998 4999 ``timestamp=on|off`` 5000 Prefix messages with a timestamp. Default is off. 5001 5002 ``guest-name=on|off`` 5003 Prefix messages with guest name but only if -name guest option is set 5004 otherwise the option is ignored. Default is off. 5005ERST 5006 5007DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 5008 "-dump-vmstate <file>\n" 5009 " Output vmstate information in JSON format to file.\n" 5010 " Use the scripts/vmstate-static-checker.py file to\n" 5011 " check for possible regressions in migration code\n" 5012 " by comparing two such vmstate dumps.\n", 5013 QEMU_ARCH_ALL) 5014SRST 5015``-dump-vmstate file`` 5016 Dump json-encoded vmstate information for current machine type to 5017 file in file 5018ERST 5019 5020DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 5021 "-enable-sync-profile\n" 5022 " enable synchronization profiling\n", 5023 QEMU_ARCH_ALL) 5024SRST 5025``-enable-sync-profile`` 5026 Enable synchronization profiling. 5027ERST 5028 5029#if defined(CONFIG_TCG) && defined(CONFIG_LINUX) 5030DEF("perfmap", 0, QEMU_OPTION_perfmap, 5031 "-perfmap generate a /tmp/perf-${pid}.map file for perf\n", 5032 QEMU_ARCH_ALL) 5033SRST 5034``-perfmap`` 5035 Generate a map file for Linux perf tools that will allow basic profiling 5036 information to be broken down into basic blocks. 5037ERST 5038 5039DEF("jitdump", 0, QEMU_OPTION_jitdump, 5040 "-jitdump generate a jit-${pid}.dump file for perf\n", 5041 QEMU_ARCH_ALL) 5042SRST 5043``-jitdump`` 5044 Generate a dump file for Linux perf tools that maps basic blocks to symbol 5045 names, line numbers and JITted code. 5046ERST 5047#endif 5048 5049DEFHEADING() 5050 5051DEFHEADING(Generic object creation:) 5052 5053DEF("object", HAS_ARG, QEMU_OPTION_object, 5054 "-object TYPENAME[,PROP1=VALUE1,...]\n" 5055 " create a new object of type TYPENAME setting properties\n" 5056 " in the order they are specified. Note that the 'id'\n" 5057 " property must be set. These objects are placed in the\n" 5058 " '/objects' path.\n", 5059 QEMU_ARCH_ALL) 5060SRST 5061``-object typename[,prop1=value1,...]`` 5062 Create a new object of type typename setting properties in the order 5063 they are specified. Note that the 'id' property must be set. These 5064 objects are placed in the '/objects' path. 5065 5066 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,offset=offset,readonly=on|off,rom=on|off|auto`` 5067 Creates a memory file backend object, which can be used to back 5068 the guest RAM with huge pages. 5069 5070 The ``id`` parameter is a unique ID that will be used to 5071 reference this memory region in other parameters, e.g. ``-numa``, 5072 ``-device nvdimm``, etc. 5073 5074 The ``size`` option provides the size of the memory region, and 5075 accepts common suffixes, e.g. ``500M``. 5076 5077 The ``mem-path`` provides the path to either a shared memory or 5078 huge page filesystem mount. 5079 5080 The ``share`` boolean option determines whether the memory 5081 region is marked as private to QEMU, or shared. The latter 5082 allows a co-operating external process to access the QEMU memory 5083 region. 5084 5085 The ``share`` is also required for pvrdma devices due to 5086 limitations in the RDMA API provided by Linux. 5087 5088 Setting share=on might affect the ability to configure NUMA 5089 bindings for the memory backend under some circumstances, see 5090 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 5091 source tree for additional details. 5092 5093 Setting the ``discard-data`` boolean option to on indicates that 5094 file contents can be destroyed when QEMU exits, to avoid 5095 unnecessarily flushing data to the backing file. Note that 5096 ``discard-data`` is only an optimization, and QEMU might not 5097 discard file contents if it aborts unexpectedly or is terminated 5098 using SIGKILL. 5099 5100 The ``merge`` boolean option enables memory merge, also known as 5101 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 5102 the pages for memory deduplication. 5103 5104 Setting the ``dump`` boolean option to off excludes the memory 5105 from core dumps. This feature is also known as MADV\_DONTDUMP. 5106 5107 The ``prealloc`` boolean option enables memory preallocation. 5108 5109 The ``host-nodes`` option binds the memory range to a list of 5110 NUMA host nodes. 5111 5112 The ``policy`` option sets the NUMA policy to one of the 5113 following values: 5114 5115 ``default`` 5116 default host policy 5117 5118 ``preferred`` 5119 prefer the given host node list for allocation 5120 5121 ``bind`` 5122 restrict memory allocation to the given host node list 5123 5124 ``interleave`` 5125 interleave memory allocations across the given host node 5126 list 5127 5128 The ``align`` option specifies the base address alignment when 5129 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 5130 ``2M``. Some backend store specified by ``mem-path`` requires an 5131 alignment different than the default one used by QEMU, eg the 5132 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 5133 such cases, users can specify the required alignment via this 5134 option. 5135 5136 The ``offset`` option specifies the offset into the target file 5137 that the region starts at. You can use this parameter to back 5138 multiple regions with a single file. 5139 5140 The ``pmem`` option specifies whether the backing file specified 5141 by ``mem-path`` is in host persistent memory that can be 5142 accessed using the SNIA NVM programming model (e.g. Intel 5143 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 5144 operations to guarantee the persistence of its own writes to 5145 ``mem-path`` (e.g. in vNVDIMM label emulation and live 5146 migration). Also, we will map the backend-file with MAP\_SYNC 5147 flag, which ensures the file metadata is in sync for 5148 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 5149 requires support from both the host kernel (since Linux kernel 5150 4.15) and the filesystem of ``mem-path`` mounted with DAX 5151 option. 5152 5153 The ``readonly`` option specifies whether the backing file is opened 5154 read-only or read-write (default). 5155 5156 The ``rom`` option specifies whether to create Read Only Memory 5157 (ROM) that cannot be modified by the VM. Any write attempts to such 5158 ROM will be denied. Most use cases want proper RAM instead of ROM. 5159 However, selected use cases, like R/O NVDIMMs, can benefit from 5160 ROM. If set to ``on``, create ROM; if set to ``off``, create 5161 writable RAM; if set to ``auto`` (default), the value of the 5162 ``readonly`` option is used. This option is primarily helpful when 5163 we want to have writable RAM in configurations that would 5164 traditionally create ROM before the ``rom`` option was introduced: 5165 VM templating, where we want to open a file readonly 5166 (``readonly=on``) and mark the memory to be private for QEMU 5167 (``share=off``). For this use case, we need writable RAM instead 5168 of ROM, and want to also set ``rom=off``. 5169 5170 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave`` 5171 Creates a memory backend object, which can be used to back the 5172 guest RAM. Memory backend objects offer more control than the 5173 ``-m`` option that is traditionally used to define guest RAM. 5174 Please refer to ``memory-backend-file`` for a description of the 5175 options. 5176 5177 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size`` 5178 Creates an anonymous memory file backend object, which allows 5179 QEMU to share the memory with an external process (e.g. when 5180 using vhost-user). The memory is allocated with memfd and 5181 optional sealing. (Linux only) 5182 5183 The ``seal`` option creates a sealed-file, that will block 5184 further resizing the memory ('on' by default). 5185 5186 The ``hugetlb`` option specify the file to be created resides in 5187 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 5188 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 5189 the hugetlb page size on systems that support multiple hugetlb 5190 page sizes (it must be a power of 2 value supported by the 5191 system). 5192 5193 In some versions of Linux, the ``hugetlb`` option is 5194 incompatible with the ``seal`` option (requires at least Linux 5195 4.16). 5196 5197 Please refer to ``memory-backend-file`` for a description of the 5198 other options. 5199 5200 The ``share`` boolean option is on by default with memfd. 5201 5202 ``-object iommufd,id=id[,fd=fd]`` 5203 Creates an iommufd backend which allows control of DMA mapping 5204 through the ``/dev/iommu`` device. 5205 5206 The ``id`` parameter is a unique ID which frontends (such as 5207 vfio-pci of vdpa) will use to connect with the iommufd backend. 5208 5209 The ``fd`` parameter is an optional pre-opened file descriptor 5210 resulting from ``/dev/iommu`` opening. Usually the iommufd is shared 5211 across all subsystems, bringing the benefit of centralized 5212 reference counting. 5213 5214 ``-object rng-builtin,id=id`` 5215 Creates a random number generator backend which obtains entropy 5216 from QEMU builtin functions. The ``id`` parameter is a unique ID 5217 that will be used to reference this entropy backend from the 5218 ``virtio-rng`` device. By default, the ``virtio-rng`` device 5219 uses this RNG backend. 5220 5221 ``-object rng-random,id=id,filename=/dev/random`` 5222 Creates a random number generator backend which obtains entropy 5223 from a device on the host. The ``id`` parameter is a unique ID 5224 that will be used to reference this entropy backend from the 5225 ``virtio-rng`` device. The ``filename`` parameter specifies 5226 which file to obtain entropy from and if omitted defaults to 5227 ``/dev/urandom``. 5228 5229 ``-object rng-egd,id=id,chardev=chardevid`` 5230 Creates a random number generator backend which obtains entropy 5231 from an external daemon running on the host. The ``id`` 5232 parameter is a unique ID that will be used to reference this 5233 entropy backend from the ``virtio-rng`` device. The ``chardev`` 5234 parameter is the unique ID of a character device backend that 5235 provides the connection to the RNG daemon. 5236 5237 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 5238 Creates a TLS anonymous credentials object, which can be used to 5239 provide TLS support on network backends. The ``id`` parameter is 5240 a unique ID which network backends will use to access the 5241 credentials. The ``endpoint`` is either ``server`` or ``client`` 5242 depending on whether the QEMU network backend that uses the 5243 credentials will be acting as a client or as a server. If 5244 ``verify-peer`` is enabled (the default) then once the handshake 5245 is completed, the peer credentials will be verified, though this 5246 is a no-op for anonymous credentials. 5247 5248 The dir parameter tells QEMU where to find the credential files. 5249 For server endpoints, this directory may contain a file 5250 dh-params.pem providing diffie-hellman parameters to use for the 5251 TLS server. If the file is missing, QEMU will generate a set of 5252 DH parameters at startup. This is a computationally expensive 5253 operation that consumes random pool entropy, so it is 5254 recommended that a persistent set of parameters be generated 5255 upfront and saved. 5256 5257 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5258 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5259 can be used to provide TLS support on network backends. The 5260 ``id`` parameter is a unique ID which network backends will use 5261 to access the credentials. The ``endpoint`` is either ``server`` 5262 or ``client`` depending on whether the QEMU network backend that 5263 uses the credentials will be acting as a client or as a server. 5264 For clients only, ``username`` is the username which will be 5265 sent to the server. If omitted it defaults to "qemu". 5266 5267 The dir parameter tells QEMU where to find the keys file. It is 5268 called "dir/keys.psk" and contains "username:key" pairs. This 5269 file can most easily be created using the GnuTLS ``psktool`` 5270 program. 5271 5272 For server endpoints, dir may also contain a file dh-params.pem 5273 providing diffie-hellman parameters to use for the TLS server. 5274 If the file is missing, QEMU will generate a set of DH 5275 parameters at startup. This is a computationally expensive 5276 operation that consumes random pool entropy, so it is 5277 recommended that a persistent set of parameters be generated up 5278 front and saved. 5279 5280 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5281 Creates a TLS anonymous credentials object, which can be used to 5282 provide TLS support on network backends. The ``id`` parameter is 5283 a unique ID which network backends will use to access the 5284 credentials. The ``endpoint`` is either ``server`` or ``client`` 5285 depending on whether the QEMU network backend that uses the 5286 credentials will be acting as a client or as a server. If 5287 ``verify-peer`` is enabled (the default) then once the handshake 5288 is completed, the peer credentials will be verified. With x509 5289 certificates, this implies that the clients must be provided 5290 with valid client certificates too. 5291 5292 The dir parameter tells QEMU where to find the credential files. 5293 For server endpoints, this directory may contain a file 5294 dh-params.pem providing diffie-hellman parameters to use for the 5295 TLS server. If the file is missing, QEMU will generate a set of 5296 DH parameters at startup. This is a computationally expensive 5297 operation that consumes random pool entropy, so it is 5298 recommended that a persistent set of parameters be generated 5299 upfront and saved. 5300 5301 For x509 certificate credentials the directory will contain 5302 further files providing the x509 certificates. The certificates 5303 must be stored in PEM format, in filenames ca-cert.pem, 5304 ca-crl.pem (optional), server-cert.pem (only servers), 5305 server-key.pem (only servers), client-cert.pem (only clients), 5306 and client-key.pem (only clients). 5307 5308 For the server-key.pem and client-key.pem files which contain 5309 sensitive private keys, it is possible to use an encrypted 5310 version by providing the passwordid parameter. This provides the 5311 ID of a previously created ``secret`` object containing the 5312 password for decryption. 5313 5314 The priority parameter allows to override the global default 5315 priority used by gnutls. This can be useful if the system 5316 administrator needs to use a weaker set of crypto priorities for 5317 QEMU without potentially forcing the weakness onto all 5318 applications. Or conversely if one wants wants a stronger 5319 default for QEMU than for all other applications, they can do 5320 this through this parameter. Its format is a gnutls priority 5321 string as described at 5322 https://gnutls.org/manual/html_node/Priority-Strings.html. 5323 5324 ``-object tls-cipher-suites,id=id,priority=priority`` 5325 Creates a TLS cipher suites object, which can be used to control 5326 the TLS cipher/protocol algorithms that applications are permitted 5327 to use. 5328 5329 The ``id`` parameter is a unique ID which frontends will use to 5330 access the ordered list of permitted TLS cipher suites from the 5331 host. 5332 5333 The ``priority`` parameter allows to override the global default 5334 priority used by gnutls. This can be useful if the system 5335 administrator needs to use a weaker set of crypto priorities for 5336 QEMU without potentially forcing the weakness onto all 5337 applications. Or conversely if one wants wants a stronger 5338 default for QEMU than for all other applications, they can do 5339 this through this parameter. Its format is a gnutls priority 5340 string as described at 5341 https://gnutls.org/manual/html_node/Priority-Strings.html. 5342 5343 An example of use of this object is to control UEFI HTTPS Boot. 5344 The tls-cipher-suites object exposes the ordered list of permitted 5345 TLS cipher suites from the host side to the guest firmware, via 5346 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5347 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5348 guest-side TLS. 5349 5350 In the following example, the priority at which the host-side policy 5351 is retrieved is given by the ``priority`` property. 5352 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5353 refer to /etc/crypto-policies/back-ends/gnutls.config. 5354 5355 .. parsed-literal:: 5356 5357 # |qemu_system| \\ 5358 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5359 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5360 5361 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5362 Interval t can't be 0, this filter batches the packet delivery: 5363 all packets arriving in a given interval on netdev netdevid are 5364 delayed until the end of the interval. Interval is in 5365 microseconds. ``status`` is optional that indicate whether the 5366 netfilter is on (enabled) or off (disabled), the default status 5367 for netfilter will be 'on'. 5368 5369 queue all\|rx\|tx is an option that can be applied to any 5370 netfilter. 5371 5372 ``all``: the filter is attached both to the receive and the 5373 transmit queue of the netdev (default). 5374 5375 ``rx``: the filter is attached to the receive queue of the 5376 netdev, where it will receive packets sent to the netdev. 5377 5378 ``tx``: the filter is attached to the transmit queue of the 5379 netdev, where it will receive packets sent by the netdev. 5380 5381 position head\|tail\|id=<id> is an option to specify where the 5382 filter should be inserted in the filter list. It can be applied 5383 to any netfilter. 5384 5385 ``head``: the filter is inserted at the head of the filter list, 5386 before any existing filters. 5387 5388 ``tail``: the filter is inserted at the tail of the filter list, 5389 behind any existing filters (default). 5390 5391 ``id=<id>``: the filter is inserted before or behind the filter 5392 specified by <id>, see the insert option below. 5393 5394 insert behind\|before is an option to specify where to insert 5395 the new filter relative to the one specified with 5396 position=id=<id>. It can be applied to any netfilter. 5397 5398 ``before``: insert before the specified filter. 5399 5400 ``behind``: insert behind the specified filter (default). 5401 5402 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5403 filter-mirror on netdev netdevid,mirror net packet to 5404 chardevchardevid, if it has the vnet\_hdr\_support flag, 5405 filter-mirror will mirror packet with vnet\_hdr\_len. 5406 5407 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5408 filter-redirector on netdev netdevid,redirect filter's net 5409 packet to chardev chardevid,and redirect indev's packet to 5410 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5411 will redirect packet with vnet\_hdr\_len. Create a 5412 filter-redirector we need to differ outdev id from indev id, id 5413 can not be the same. we can just use indev or outdev, but at 5414 least one of indev or outdev need to be specified. 5415 5416 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5417 Filter-rewriter is a part of COLO project.It will rewrite tcp 5418 packet to secondary from primary to keep secondary tcp 5419 connection,and rewrite tcp packet to primary from secondary make 5420 tcp packet can be handled by client.if it has the 5421 vnet\_hdr\_support flag, we can parse packet with vnet header. 5422 5423 usage: colo secondary: -object 5424 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5425 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5426 filter-rewriter,id=rew0,netdev=hn0,queue=all 5427 5428 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5429 Dump the network traffic on netdev dev to the file specified by 5430 filename. At most len bytes (64k by default) per packet are 5431 stored. The file format is libpcap, so it can be analyzed with 5432 tools such as tcpdump or Wireshark. 5433 5434 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]`` 5435 Colo-compare gets packet from primary\_in chardevid and 5436 secondary\_in, then compare whether the payload of primary packet 5437 and secondary packet are the same. If same, it will output 5438 primary packet to out\_dev, else it will notify COLO-framework to do 5439 checkpoint and send primary packet to out\_dev. In order to 5440 improve efficiency, we need to put the task of comparison in 5441 another iothread. If it has the vnet\_hdr\_support flag, 5442 colo compare will send/recv packet with vnet\_hdr\_len. 5443 The compare\_timeout=@var{ms} determines the maximum time of the 5444 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5445 is to set the period of scanning expired primary node network packets. 5446 The max\_queue\_size=@var{size} is to set the max compare queue 5447 size depend on user environment. 5448 If user want to use Xen COLO, need to add the notify\_dev to 5449 notify Xen colo-frame to do checkpoint. 5450 5451 COLO-compare must be used with the help of filter-mirror, 5452 filter-redirector and filter-rewriter. 5453 5454 :: 5455 5456 KVM COLO 5457 5458 primary: 5459 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5460 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5461 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5462 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5463 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5464 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5465 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5466 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5467 -object iothread,id=iothread1 5468 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5469 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5470 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5471 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5472 5473 secondary: 5474 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5475 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5476 -chardev socket,id=red0,host=3.3.3.3,port=9003 5477 -chardev socket,id=red1,host=3.3.3.3,port=9004 5478 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5479 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5480 5481 5482 Xen COLO 5483 5484 primary: 5485 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5486 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5487 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5488 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5489 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5490 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5491 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5492 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5493 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5494 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5495 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5496 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5497 -object iothread,id=iothread1 5498 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5499 5500 secondary: 5501 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5502 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5503 -chardev socket,id=red0,host=3.3.3.3,port=9003 5504 -chardev socket,id=red1,host=3.3.3.3,port=9004 5505 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5506 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5507 5508 If you want to know the detail of above command line, you can 5509 read the colo-compare git log. 5510 5511 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5512 Creates a cryptodev backend which executes crypto operations from 5513 the QEMU cipher APIs. The id parameter is a unique ID that will 5514 be used to reference this cryptodev backend from the 5515 ``virtio-crypto`` device. The queues parameter is optional, 5516 which specify the queue number of cryptodev backend, the default 5517 of queues is 1. 5518 5519 .. parsed-literal:: 5520 5521 # |qemu_system| \\ 5522 [...] \\ 5523 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5524 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5525 [...] 5526 5527 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5528 Creates a vhost-user cryptodev backend, backed by a chardev 5529 chardevid. The id parameter is a unique ID that will be used to 5530 reference this cryptodev backend from the ``virtio-crypto`` 5531 device. The chardev should be a unix domain socket backed one. 5532 The vhost-user uses a specifically defined protocol to pass 5533 vhost ioctl replacement messages to an application on the other 5534 end of the socket. The queues parameter is optional, which 5535 specify the queue number of cryptodev backend for multiqueue 5536 vhost-user, the default of queues is 1. 5537 5538 .. parsed-literal:: 5539 5540 # |qemu_system| \\ 5541 [...] \\ 5542 -chardev socket,id=chardev0,path=/path/to/socket \\ 5543 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5544 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5545 [...] 5546 5547 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5548 \ 5549 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5550 Defines a secret to store a password, encryption key, or some 5551 other sensitive data. The sensitive data can either be passed 5552 directly via the data parameter, or indirectly via the file 5553 parameter. Using the data parameter is insecure unless the 5554 sensitive data is encrypted. 5555 5556 The sensitive data can be provided in raw format (the default), 5557 or base64. When encoded as JSON, the raw format only supports 5558 valid UTF-8 characters, so base64 is recommended for sending 5559 binary data. QEMU will convert from which ever format is 5560 provided to the format it needs internally. eg, an RBD password 5561 can be provided in raw format, even though it will be base64 5562 encoded when passed onto the RBD sever. 5563 5564 For added protection, it is possible to encrypt the data 5565 associated with a secret using the AES-256-CBC cipher. Use of 5566 encryption is indicated by providing the keyid and iv 5567 parameters. The keyid parameter provides the ID of a previously 5568 defined secret that contains the AES-256 decryption key. This 5569 key should be 32-bytes long and be base64 encoded. The iv 5570 parameter provides the random initialization vector used for 5571 encryption of this particular secret and should be a base64 5572 encrypted string of the 16-byte IV. 5573 5574 The simplest (insecure) usage is to provide the secret inline 5575 5576 .. parsed-literal:: 5577 5578 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5579 5580 The simplest secure usage is to provide the secret via a file 5581 5582 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5583 secret,id=sec0,file=mypasswd.txt,format=raw 5584 5585 For greater security, AES-256-CBC should be used. To illustrate 5586 usage, consider the openssl command line tool which can encrypt 5587 the data. Note that when encrypting, the plaintext must be 5588 padded to the cipher block size (32 bytes) using the standard 5589 PKCS#5/6 compatible padding algorithm. 5590 5591 First a master key needs to be created in base64 encoding: 5592 5593 :: 5594 5595 # openssl rand -base64 32 > key.b64 5596 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5597 5598 Each secret to be encrypted needs to have a random 5599 initialization vector generated. These do not need to be kept 5600 secret 5601 5602 :: 5603 5604 # openssl rand -base64 16 > iv.b64 5605 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5606 5607 The secret to be defined can now be encrypted, in this case 5608 we're telling openssl to base64 encode the result, but it could 5609 be left as raw bytes if desired. 5610 5611 :: 5612 5613 # SECRET=$(printf "letmein" | 5614 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5615 5616 When launching QEMU, create a master secret pointing to 5617 ``key.b64`` and specify that to be used to decrypt the user 5618 password. Pass the contents of ``iv.b64`` to the second secret 5619 5620 .. parsed-literal:: 5621 5622 # |qemu_system| \\ 5623 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5624 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5625 data=$SECRET,iv=$(<iv.b64) 5626 5627 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file,kernel-hashes=on|off]`` 5628 Create a Secure Encrypted Virtualization (SEV) guest object, 5629 which can be used to provide the guest memory encryption support 5630 on AMD processors. 5631 5632 When memory encryption is enabled, one of the physical address 5633 bit (aka the C-bit) is utilized to mark if a memory page is 5634 protected. The ``cbitpos`` is used to provide the C-bit 5635 position. The C-bit position is Host family dependent hence user 5636 must provide this value. On EPYC, the value should be 47. 5637 5638 When memory encryption is enabled, we loose certain bits in 5639 physical address space. The ``reduced-phys-bits`` is used to 5640 provide the number of bits we loose in physical address space. 5641 Similar to C-bit, the value is Host family dependent. On EPYC, 5642 a guest will lose a maximum of 1 bit, so the value should be 1. 5643 5644 The ``sev-device`` provides the device file to use for 5645 communicating with the SEV firmware running inside AMD Secure 5646 Processor. The default device is '/dev/sev'. If hardware 5647 supports memory encryption then /dev/sev devices are created by 5648 CCP driver. 5649 5650 The ``policy`` provides the guest policy to be enforced by the 5651 SEV firmware and restrict what configuration and operational 5652 commands can be performed on this guest by the hypervisor. The 5653 policy should be provided by the guest owner and is bound to the 5654 guest and cannot be changed throughout the lifetime of the 5655 guest. The default is 0. 5656 5657 If guest ``policy`` allows sharing the key with another SEV 5658 guest then ``handle`` can be use to provide handle of the guest 5659 from which to share the key. 5660 5661 The ``dh-cert-file`` and ``session-file`` provides the guest 5662 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5663 and session parameters are used for establishing a cryptographic 5664 session with the guest owner to negotiate keys used for 5665 attestation. The file must be encoded in base64. 5666 5667 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5668 cmdline to a designated guest firmware page for measured Linux 5669 boot with -kernel. The default is off. (Since 6.2) 5670 5671 e.g to launch a SEV guest 5672 5673 .. parsed-literal:: 5674 5675 # |qemu_system_x86| \\ 5676 ...... \\ 5677 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=1 \\ 5678 -machine ...,memory-encryption=sev0 \\ 5679 ..... 5680 5681 ``-object authz-simple,id=id,identity=string`` 5682 Create an authorization object that will control access to 5683 network services. 5684 5685 The ``identity`` parameter is identifies the user and its format 5686 depends on the network service that authorization object is 5687 associated with. For authorizing based on TLS x509 certificates, 5688 the identity must be the x509 distinguished name. Note that care 5689 must be taken to escape any commas in the distinguished name. 5690 5691 An example authorization object to validate a x509 distinguished 5692 name would look like: 5693 5694 .. parsed-literal:: 5695 5696 # |qemu_system| \\ 5697 ... \\ 5698 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5699 ... 5700 5701 Note the use of quotes due to the x509 distinguished name 5702 containing whitespace, and escaping of ','. 5703 5704 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5705 Create an authorization object that will control access to 5706 network services. 5707 5708 The ``filename`` parameter is the fully qualified path to a file 5709 containing the access control list rules in JSON format. 5710 5711 An example set of rules that match against SASL usernames might 5712 look like: 5713 5714 :: 5715 5716 { 5717 "rules": [ 5718 { "match": "fred", "policy": "allow", "format": "exact" }, 5719 { "match": "bob", "policy": "allow", "format": "exact" }, 5720 { "match": "danb", "policy": "deny", "format": "glob" }, 5721 { "match": "dan*", "policy": "allow", "format": "exact" }, 5722 ], 5723 "policy": "deny" 5724 } 5725 5726 When checking access the object will iterate over all the rules 5727 and the first rule to match will have its ``policy`` value 5728 returned as the result. If no rules match, then the default 5729 ``policy`` value is returned. 5730 5731 The rules can either be an exact string match, or they can use 5732 the simple UNIX glob pattern matching to allow wildcards to be 5733 used. 5734 5735 If ``refresh`` is set to true the file will be monitored and 5736 automatically reloaded whenever its content changes. 5737 5738 As with the ``authz-simple`` object, the format of the identity 5739 strings being matched depends on the network service, but is 5740 usually a TLS x509 distinguished name, or a SASL username. 5741 5742 An example authorization object to validate a SASL username 5743 would look like: 5744 5745 .. parsed-literal:: 5746 5747 # |qemu_system| \\ 5748 ... \\ 5749 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5750 ... 5751 5752 ``-object authz-pam,id=id,service=string`` 5753 Create an authorization object that will control access to 5754 network services. 5755 5756 The ``service`` parameter provides the name of a PAM service to 5757 use for authorization. It requires that a file 5758 ``/etc/pam.d/service`` exist to provide the configuration for 5759 the ``account`` subsystem. 5760 5761 An example authorization object to validate a TLS x509 5762 distinguished name would look like: 5763 5764 .. parsed-literal:: 5765 5766 # |qemu_system| \\ 5767 ... \\ 5768 -object authz-pam,id=auth0,service=qemu-vnc \\ 5769 ... 5770 5771 There would then be a corresponding config file for PAM at 5772 ``/etc/pam.d/qemu-vnc`` that contains: 5773 5774 :: 5775 5776 account requisite pam_listfile.so item=user sense=allow \ 5777 file=/etc/qemu/vnc.allow 5778 5779 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5780 of x509 distinguished names that are permitted access 5781 5782 :: 5783 5784 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5785 5786 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5787 Creates a dedicated event loop thread that devices can be 5788 assigned to. This is known as an IOThread. By default device 5789 emulation happens in vCPU threads or the main event loop thread. 5790 This can become a scalability bottleneck. IOThreads allow device 5791 emulation and I/O to run on other host CPUs. 5792 5793 The ``id`` parameter is a unique ID that will be used to 5794 reference this IOThread from ``-device ...,iothread=id``. 5795 Multiple devices can be assigned to an IOThread. Note that not 5796 all devices support an ``iothread`` parameter. 5797 5798 The ``query-iothreads`` QMP command lists IOThreads and reports 5799 their thread IDs so that the user can configure host CPU 5800 pinning/affinity. 5801 5802 IOThreads use an adaptive polling algorithm to reduce event loop 5803 latency. Instead of entering a blocking system call to monitor 5804 file descriptors and then pay the cost of being woken up when an 5805 event occurs, the polling algorithm spins waiting for events for 5806 a short time. The algorithm's default parameters are suitable 5807 for many cases but can be adjusted based on knowledge of the 5808 workload and/or host device latency. 5809 5810 The ``poll-max-ns`` parameter is the maximum number of 5811 nanoseconds to busy wait for events. Polling can be disabled by 5812 setting this value to 0. 5813 5814 The ``poll-grow`` parameter is the multiplier used to increase 5815 the polling time when the algorithm detects it is missing events 5816 due to not polling long enough. 5817 5818 The ``poll-shrink`` parameter is the divisor used to decrease 5819 the polling time when the algorithm detects it is spending too 5820 long polling without encountering events. 5821 5822 The ``aio-max-batch`` parameter is the maximum number of requests 5823 in a batch for the AIO engine, 0 means that the engine will use 5824 its default. 5825 5826 The IOThread parameters can be modified at run-time using the 5827 ``qom-set`` command (where ``iothread1`` is the IOThread's 5828 ``id``): 5829 5830 :: 5831 5832 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5833ERST 5834 5835 5836HXCOMM This is the last statement. Insert new options before this line! 5837 5838#undef DEF 5839#undef DEFHEADING 5840#undef ARCHHEADING 5841
