xref: /qemu/docs/user/main.rst (revision 83fb360d6a60b0a77dce3d3643d1a5311a235e58)
1 QEMU User space emulator
2 ========================
3 
4 Supported Operating Systems
5 ---------------------------
6 
7 The following OS are supported in user space emulation:
8 
9 -  Linux (referred as qemu-linux-user)
10 
11 -  BSD (referred as qemu-bsd-user)
12 
13 Features
14 --------
15 
16 QEMU user space emulation has the following notable features:
17 
18 **System call translation:**
19    QEMU includes a generic system call translator. This means that the
20    parameters of the system calls can be converted to fix endianness and
21    32/64-bit mismatches between hosts and targets. IOCTLs can be
22    converted too.
23 
24 **POSIX signal handling:**
25    QEMU can redirect to the running program all signals coming from the
26    host (such as ``SIGALRM``), as well as synthesize signals from
27    virtual CPU exceptions (for example ``SIGFPE`` when the program
28    executes a division by zero).
29 
30    QEMU relies on the host kernel to emulate most signal system calls,
31    for example to emulate the signal mask. On Linux, QEMU supports both
32    normal and real-time signals.
33 
34 **Threading:**
35    On Linux, QEMU can emulate the ``clone`` syscall and create a real
36    host thread (with a separate virtual CPU) for each emulated thread.
37    Note that not all targets currently emulate atomic operations
38    correctly. x86 and Arm use a global lock in order to preserve their
39    semantics.
40 
41 QEMU was conceived so that ultimately it can emulate itself. Although it
42 is not very useful, it is an important test to show the power of the
43 emulator.
44 
45 Linux User space emulator
46 -------------------------
47 
48 Command line options
49 ~~~~~~~~~~~~~~~~~~~~
50 
51 ::
52 
53    qemu-i386 [-h] [-d] [-L path] [-s size] [-cpu model] [-g port] [-B offset] [-R size] program [arguments...]
54 
55 ``-h``
56    Print the help
57 
58 ``-L path``
59    Set the x86 elf interpreter prefix (default=/usr/local/qemu-i386)
60 
61 ``-s size``
62    Set the x86 stack size in bytes (default=524288)
63 
64 ``-cpu model``
65    Select CPU model (-cpu help for list and additional feature
66    selection)
67 
68 ``-E var=value``
69    Set environment var to value.
70 
71 ``-U var``
72    Remove var from the environment.
73 
74 ``-B offset``
75    Offset guest address by the specified number of bytes. This is useful
76    when the address region required by guest applications is reserved on
77    the host. This option is currently only supported on some hosts.
78 
79 ``-R size``
80    Pre-allocate a guest virtual address space of the given size (in
81    bytes). \"G\", \"M\", and \"k\" suffixes may be used when specifying
82    the size.
83 
84 Debug options:
85 
86 ``-d item1,...``
87    Activate logging of the specified items (use '-d help' for a list of
88    log items)
89 
90 ``-g port``
91    Wait gdb connection to port
92 
93 ``-one-insn-per-tb``
94    Run the emulation with one guest instruction per translation block.
95    This slows down emulation a lot, but can be useful in some situations,
96    such as when trying to analyse the logs produced by the ``-d`` option.
97 
98 Environment variables:
99 
100 QEMU_STRACE
101    Print system calls and arguments similar to the 'strace' program
102    (NOTE: the actual 'strace' program will not work because the user
103    space emulator hasn't implemented ptrace). At the moment this is
104    incomplete. All system calls that don't have a specific argument
105    format are printed with information for six arguments. Many
106    flag-style arguments don't have decoders and will show up as numbers.
107 
108 Other binaries
109 ~~~~~~~~~~~~~~
110 
111 -  user mode (Alpha)
112 
113    * ``qemu-alpha`` TODO.
114 
115 -  user mode (Arm)
116 
117    * ``qemu-armeb`` TODO.
118 
119    * ``qemu-arm`` is also capable of running Arm \"Angel\" semihosted ELF
120      binaries (as implemented by the arm-elf and arm-eabi Newlib/GDB
121      configurations), and arm-uclinux bFLT format binaries.
122 
123 -  user mode (ColdFire)
124 
125 -  user mode (M68K)
126 
127    * ``qemu-m68k`` is capable of running semihosted binaries using the BDM
128      (m5xxx-ram-hosted.ld) or m68k-sim (sim.ld) syscall interfaces, and
129      coldfire uClinux bFLT format binaries.
130 
131    The binary format is detected automatically.
132 
133 -  user mode (Cris)
134 
135    * ``qemu-cris`` TODO.
136 
137 -  user mode (i386)
138 
139    * ``qemu-i386`` TODO.
140    * ``qemu-x86_64`` TODO.
141 
142 -  user mode (Microblaze)
143 
144    * ``qemu-microblaze`` TODO.
145 
146 -  user mode (MIPS)
147 
148    * ``qemu-mips`` executes 32-bit big endian MIPS binaries (MIPS O32 ABI).
149 
150    * ``qemu-mipsel`` executes 32-bit little endian MIPS binaries (MIPS O32 ABI).
151 
152    * ``qemu-mips64`` executes 64-bit big endian MIPS binaries (MIPS N64 ABI).
153 
154    * ``qemu-mips64el`` executes 64-bit little endian MIPS binaries (MIPS N64
155      ABI).
156 
157    * ``qemu-mipsn32`` executes 32-bit big endian MIPS binaries (MIPS N32 ABI).
158 
159    * ``qemu-mipsn32el`` executes 32-bit little endian MIPS binaries (MIPS N32
160      ABI).
161 
162 -  user mode (PowerPC)
163 
164    * ``qemu-ppc64`` TODO.
165    * ``qemu-ppc`` TODO.
166 
167 -  user mode (SH4)
168 
169    * ``qemu-sh4eb`` TODO.
170    * ``qemu-sh4`` TODO.
171 
172 -  user mode (SPARC)
173 
174    * ``qemu-sparc`` can execute Sparc32 binaries (Sparc32 CPU, 32 bit ABI).
175 
176    * ``qemu-sparc32plus`` can execute Sparc32 and SPARC32PLUS binaries
177      (Sparc64 CPU, 32 bit ABI).
178 
179    * ``qemu-sparc64`` can execute some Sparc64 (Sparc64 CPU, 64 bit ABI) and
180      SPARC32PLUS binaries (Sparc64 CPU, 32 bit ABI).
181 
182 BSD User space emulator
183 -----------------------
184 
185 BSD Status
186 ~~~~~~~~~~
187 
188 -  target Sparc64 on Sparc64: Some trivial programs work.
189 
190 Quick Start
191 ~~~~~~~~~~~
192 
193 In order to launch a BSD process, QEMU needs the process executable
194 itself and all the target dynamic libraries used by it.
195 
196 -  On Sparc64, you can just try to launch any process by using the
197    native libraries::
198 
199       qemu-sparc64 /bin/ls
200 
201 Command line options
202 ~~~~~~~~~~~~~~~~~~~~
203 
204 ::
205 
206    qemu-sparc64 [-h] [-d] [-L path] [-s size] [-bsd type] program [arguments...]
207 
208 ``-h``
209    Print the help
210 
211 ``-L path``
212    Set the library root path (default=/)
213 
214 ``-s size``
215    Set the stack size in bytes (default=524288)
216 
217 ``-ignore-environment``
218    Start with an empty environment. Without this option, the initial
219    environment is a copy of the caller's environment.
220 
221 ``-E var=value``
222    Set environment var to value.
223 
224 ``-U var``
225    Remove var from the environment.
226 
227 ``-bsd type``
228    Set the type of the emulated BSD Operating system. Valid values are
229    FreeBSD, NetBSD and OpenBSD (default).
230 
231 Debug options:
232 
233 ``-d item1,...``
234    Activate logging of the specified items (use '-d help' for a list of
235    log items)
236 
237 ``-p pagesize``
238    Act as if the host page size was 'pagesize' bytes
239 
240 ``-one-insn-per-tb``
241    Run the emulation with one guest instruction per translation block.
242    This slows down emulation a lot, but can be useful in some situations,
243    such as when trying to analyse the logs produced by the ``-d`` option.
244