1 /* 2 * Vhost User library 3 * 4 * Copyright (c) 2016 Red Hat, Inc. 5 * 6 * Authors: 7 * Victor Kaplansky <victork@redhat.com> 8 * Marc-André Lureau <mlureau@redhat.com> 9 * 10 * This work is licensed under the terms of the GNU GPL, version 2 or 11 * later. See the COPYING file in the top-level directory. 12 */ 13 14 #ifndef LIBVHOST_USER_H 15 #define LIBVHOST_USER_H 16 17 #include <stdint.h> 18 #include <stdbool.h> 19 #include <stddef.h> 20 #include <poll.h> 21 #include <linux/vhost.h> 22 #include <pthread.h> 23 #include "standard-headers/linux/virtio_ring.h" 24 25 /* Based on qemu/hw/virtio/vhost-user.c */ 26 #define VHOST_USER_F_PROTOCOL_FEATURES 30 27 #define VHOST_LOG_PAGE 4096 28 29 #define VIRTQUEUE_MAX_SIZE 1024 30 31 #define VHOST_MEMORY_BASELINE_NREGIONS 8 32 33 /* 34 * vhost in the kernel usually supports 509 mem slots. 509 used to be the 35 * KVM limit, it supported 512, but 3 were used for internal purposes. This 36 * limit is sufficient to support many DIMMs and virtio-mem in 37 * "dynamic-memslots" mode. 38 */ 39 #define VHOST_USER_MAX_RAM_SLOTS 509 40 41 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64) 42 43 typedef enum VhostSetConfigType { 44 VHOST_SET_CONFIG_TYPE_FRONTEND = 0, 45 VHOST_SET_CONFIG_TYPE_MIGRATION = 1, 46 } VhostSetConfigType; 47 48 /* 49 * Maximum size of virtio device config space 50 */ 51 #define VHOST_USER_MAX_CONFIG_SIZE 256 52 53 enum VhostUserProtocolFeature { 54 VHOST_USER_PROTOCOL_F_MQ = 0, 55 VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1, 56 VHOST_USER_PROTOCOL_F_RARP = 2, 57 VHOST_USER_PROTOCOL_F_REPLY_ACK = 3, 58 VHOST_USER_PROTOCOL_F_NET_MTU = 4, 59 VHOST_USER_PROTOCOL_F_BACKEND_REQ = 5, 60 VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6, 61 VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7, 62 VHOST_USER_PROTOCOL_F_PAGEFAULT = 8, 63 VHOST_USER_PROTOCOL_F_CONFIG = 9, 64 VHOST_USER_PROTOCOL_F_BACKEND_SEND_FD = 10, 65 VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11, 66 VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12, 67 VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14, 68 VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15, 69 /* Feature 16 is reserved for VHOST_USER_PROTOCOL_F_STATUS. */ 70 /* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */ 71 VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 18, 72 VHOST_USER_PROTOCOL_F_MAX 73 }; 74 75 #define VHOST_USER_PROTOCOL_FEATURE_MASK ((1 << VHOST_USER_PROTOCOL_F_MAX) - 1) 76 77 typedef enum VhostUserRequest { 78 VHOST_USER_NONE = 0, 79 VHOST_USER_GET_FEATURES = 1, 80 VHOST_USER_SET_FEATURES = 2, 81 VHOST_USER_SET_OWNER = 3, 82 VHOST_USER_RESET_OWNER = 4, 83 VHOST_USER_SET_MEM_TABLE = 5, 84 VHOST_USER_SET_LOG_BASE = 6, 85 VHOST_USER_SET_LOG_FD = 7, 86 VHOST_USER_SET_VRING_NUM = 8, 87 VHOST_USER_SET_VRING_ADDR = 9, 88 VHOST_USER_SET_VRING_BASE = 10, 89 VHOST_USER_GET_VRING_BASE = 11, 90 VHOST_USER_SET_VRING_KICK = 12, 91 VHOST_USER_SET_VRING_CALL = 13, 92 VHOST_USER_SET_VRING_ERR = 14, 93 VHOST_USER_GET_PROTOCOL_FEATURES = 15, 94 VHOST_USER_SET_PROTOCOL_FEATURES = 16, 95 VHOST_USER_GET_QUEUE_NUM = 17, 96 VHOST_USER_SET_VRING_ENABLE = 18, 97 VHOST_USER_SEND_RARP = 19, 98 VHOST_USER_NET_SET_MTU = 20, 99 VHOST_USER_SET_BACKEND_REQ_FD = 21, 100 VHOST_USER_IOTLB_MSG = 22, 101 VHOST_USER_SET_VRING_ENDIAN = 23, 102 VHOST_USER_GET_CONFIG = 24, 103 VHOST_USER_SET_CONFIG = 25, 104 VHOST_USER_CREATE_CRYPTO_SESSION = 26, 105 VHOST_USER_CLOSE_CRYPTO_SESSION = 27, 106 VHOST_USER_POSTCOPY_ADVISE = 28, 107 VHOST_USER_POSTCOPY_LISTEN = 29, 108 VHOST_USER_POSTCOPY_END = 30, 109 VHOST_USER_GET_INFLIGHT_FD = 31, 110 VHOST_USER_SET_INFLIGHT_FD = 32, 111 VHOST_USER_GPU_SET_SOCKET = 33, 112 VHOST_USER_VRING_KICK = 35, 113 VHOST_USER_GET_MAX_MEM_SLOTS = 36, 114 VHOST_USER_ADD_MEM_REG = 37, 115 VHOST_USER_REM_MEM_REG = 38, 116 VHOST_USER_GET_SHARED_OBJECT = 41, 117 VHOST_USER_MAX 118 } VhostUserRequest; 119 120 typedef enum VhostUserBackendRequest { 121 VHOST_USER_BACKEND_NONE = 0, 122 VHOST_USER_BACKEND_IOTLB_MSG = 1, 123 VHOST_USER_BACKEND_CONFIG_CHANGE_MSG = 2, 124 VHOST_USER_BACKEND_VRING_HOST_NOTIFIER_MSG = 3, 125 VHOST_USER_BACKEND_VRING_CALL = 4, 126 VHOST_USER_BACKEND_VRING_ERR = 5, 127 VHOST_USER_BACKEND_SHARED_OBJECT_ADD = 6, 128 VHOST_USER_BACKEND_SHARED_OBJECT_REMOVE = 7, 129 VHOST_USER_BACKEND_SHARED_OBJECT_LOOKUP = 8, 130 VHOST_USER_BACKEND_MAX 131 } VhostUserBackendRequest; 132 133 typedef struct VhostUserMemoryRegion { 134 uint64_t guest_phys_addr; 135 uint64_t memory_size; 136 uint64_t userspace_addr; 137 uint64_t mmap_offset; 138 } VhostUserMemoryRegion; 139 140 #define VHOST_USER_MEM_REG_SIZE (sizeof(VhostUserMemoryRegion)) 141 142 typedef struct VhostUserMemory { 143 uint32_t nregions; 144 uint32_t padding; 145 VhostUserMemoryRegion regions[VHOST_MEMORY_BASELINE_NREGIONS]; 146 } VhostUserMemory; 147 148 typedef struct VhostUserMemRegMsg { 149 uint64_t padding; 150 VhostUserMemoryRegion region; 151 } VhostUserMemRegMsg; 152 153 typedef struct VhostUserLog { 154 uint64_t mmap_size; 155 uint64_t mmap_offset; 156 } VhostUserLog; 157 158 typedef struct VhostUserConfig { 159 uint32_t offset; 160 uint32_t size; 161 uint32_t flags; 162 uint8_t region[VHOST_USER_MAX_CONFIG_SIZE]; 163 } VhostUserConfig; 164 165 static VhostUserConfig c __attribute__ ((unused)); 166 #define VHOST_USER_CONFIG_HDR_SIZE (sizeof(c.offset) \ 167 + sizeof(c.size) \ 168 + sizeof(c.flags)) 169 170 typedef struct VhostUserVringArea { 171 uint64_t u64; 172 uint64_t size; 173 uint64_t offset; 174 } VhostUserVringArea; 175 176 typedef struct VhostUserInflight { 177 uint64_t mmap_size; 178 uint64_t mmap_offset; 179 uint16_t num_queues; 180 uint16_t queue_size; 181 } VhostUserInflight; 182 183 #define UUID_LEN 16 184 185 typedef struct VhostUserShared { 186 unsigned char uuid[UUID_LEN]; 187 } VhostUserShared; 188 189 #define VU_PACKED __attribute__((packed)) 190 191 typedef struct VhostUserMsg { 192 int request; 193 194 #define VHOST_USER_VERSION_MASK (0x3) 195 #define VHOST_USER_REPLY_MASK (0x1 << 2) 196 #define VHOST_USER_NEED_REPLY_MASK (0x1 << 3) 197 uint32_t flags; 198 uint32_t size; /* the following payload size */ 199 200 union { 201 #define VHOST_USER_VRING_IDX_MASK (0xff) 202 #define VHOST_USER_VRING_NOFD_MASK (0x1 << 8) 203 uint64_t u64; 204 struct vhost_vring_state state; 205 struct vhost_vring_addr addr; 206 VhostUserMemory memory; 207 VhostUserMemRegMsg memreg; 208 VhostUserLog log; 209 VhostUserConfig config; 210 VhostUserVringArea area; 211 VhostUserInflight inflight; 212 VhostUserShared object; 213 } payload; 214 215 int fds[VHOST_MEMORY_BASELINE_NREGIONS]; 216 int fd_num; 217 uint8_t *data; 218 } VU_PACKED VhostUserMsg; 219 220 typedef struct VuDevRegion { 221 /* Guest Physical address. */ 222 uint64_t gpa; 223 /* Memory region size. */ 224 uint64_t size; 225 /* QEMU virtual address (userspace). */ 226 uint64_t qva; 227 /* Starting offset in our mmaped space. */ 228 uint64_t mmap_offset; 229 /* Start address of mmaped space. */ 230 uint64_t mmap_addr; 231 } VuDevRegion; 232 233 typedef struct VuDev VuDev; 234 235 typedef uint64_t (*vu_get_features_cb) (VuDev *dev); 236 typedef void (*vu_set_features_cb) (VuDev *dev, uint64_t features); 237 typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg, 238 int *do_reply); 239 typedef bool (*vu_read_msg_cb) (VuDev *dev, int sock, VhostUserMsg *vmsg); 240 typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool started); 241 typedef bool (*vu_queue_is_processed_in_order_cb) (VuDev *dev, int qidx); 242 typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t len); 243 typedef int (*vu_set_config_cb) (VuDev *dev, const uint8_t *data, 244 uint32_t offset, uint32_t size, 245 uint32_t flags); 246 typedef int (*vu_get_shared_object_cb) (VuDev *dev, const unsigned char *uuid); 247 248 typedef struct VuDevIface { 249 /* called by VHOST_USER_GET_FEATURES to get the features bitmask */ 250 vu_get_features_cb get_features; 251 /* enable vhost implementation features */ 252 vu_set_features_cb set_features; 253 /* get the protocol feature bitmask from the underlying vhost 254 * implementation */ 255 vu_get_features_cb get_protocol_features; 256 /* enable protocol features in the underlying vhost implementation. */ 257 vu_set_features_cb set_protocol_features; 258 /* process_msg is called for each vhost-user message received */ 259 /* skip libvhost-user processing if return value != 0 */ 260 vu_process_msg_cb process_msg; 261 /* tells when queues can be processed */ 262 vu_queue_set_started_cb queue_set_started; 263 /* 264 * If the queue is processed in order, in which case it will be 265 * resumed to vring.used->idx. This can help to support resuming 266 * on unmanaged exit/crash. 267 */ 268 vu_queue_is_processed_in_order_cb queue_is_processed_in_order; 269 /* get the config space of the device */ 270 vu_get_config_cb get_config; 271 /* set the config space of the device */ 272 vu_set_config_cb set_config; 273 /* get virtio shared object from the underlying vhost implementation. */ 274 vu_get_shared_object_cb get_shared_object; 275 } VuDevIface; 276 277 typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx); 278 279 typedef struct VuRing { 280 unsigned int num; 281 struct vring_desc *desc; 282 struct vring_avail *avail; 283 struct vring_used *used; 284 uint64_t log_guest_addr; 285 uint32_t flags; 286 } VuRing; 287 288 typedef struct VuDescStateSplit { 289 /* Indicate whether this descriptor is inflight or not. 290 * Only available for head-descriptor. */ 291 uint8_t inflight; 292 293 /* Padding */ 294 uint8_t padding[5]; 295 296 /* Maintain a list for the last batch of used descriptors. 297 * Only available when batching is used for submitting */ 298 uint16_t next; 299 300 /* Used to preserve the order of fetching available descriptors. 301 * Only available for head-descriptor. */ 302 uint64_t counter; 303 } VuDescStateSplit; 304 305 typedef struct VuVirtqInflight { 306 /* The feature flags of this region. Now it's initialized to 0. */ 307 uint64_t features; 308 309 /* The version of this region. It's 1 currently. 310 * Zero value indicates a vm reset happened. */ 311 uint16_t version; 312 313 /* 314 * The size of VuDescStateSplit array. It's equal to the virtqueue size. 315 * Backend could get it from queue size field of VhostUserInflight. 316 */ 317 uint16_t desc_num; 318 319 /* The head of list that track the last batch of used descriptors. */ 320 uint16_t last_batch_head; 321 322 /* Storing the idx value of used ring */ 323 uint16_t used_idx; 324 325 /* Used to track the state of each descriptor in descriptor table */ 326 VuDescStateSplit desc[]; 327 } VuVirtqInflight; 328 329 typedef struct VuVirtqInflightDesc { 330 uint16_t index; 331 uint64_t counter; 332 } VuVirtqInflightDesc; 333 334 typedef struct VuVirtq { 335 VuRing vring; 336 337 VuVirtqInflight *inflight; 338 339 VuVirtqInflightDesc *resubmit_list; 340 341 uint16_t resubmit_num; 342 343 uint64_t counter; 344 345 /* Next head to pop */ 346 uint16_t last_avail_idx; 347 348 /* Last avail_idx read from VQ. */ 349 uint16_t shadow_avail_idx; 350 351 uint16_t used_idx; 352 353 /* Last used index value we have signalled on */ 354 uint16_t signalled_used; 355 356 /* Last used index value we have signalled on */ 357 bool signalled_used_valid; 358 359 /* Notification enabled? */ 360 bool notification; 361 362 unsigned int inuse; 363 364 vu_queue_handler_cb handler; 365 366 int call_fd; 367 int kick_fd; 368 int err_fd; 369 unsigned int enable; 370 bool started; 371 372 /* Guest addresses of our ring */ 373 struct vhost_vring_addr vra; 374 } VuVirtq; 375 376 enum VuWatchCondtion { 377 VU_WATCH_IN = POLLIN, 378 VU_WATCH_OUT = POLLOUT, 379 VU_WATCH_PRI = POLLPRI, 380 VU_WATCH_ERR = POLLERR, 381 VU_WATCH_HUP = POLLHUP, 382 }; 383 384 typedef void (*vu_panic_cb) (VuDev *dev, const char *err); 385 typedef void (*vu_watch_cb) (VuDev *dev, int condition, void *data); 386 typedef void (*vu_set_watch_cb) (VuDev *dev, int fd, int condition, 387 vu_watch_cb cb, void *data); 388 typedef void (*vu_remove_watch_cb) (VuDev *dev, int fd); 389 390 typedef struct VuDevInflightInfo { 391 int fd; 392 void *addr; 393 uint64_t size; 394 } VuDevInflightInfo; 395 396 struct VuDev { 397 int sock; 398 uint32_t nregions; 399 VuDevRegion *regions; 400 VuVirtq *vq; 401 VuDevInflightInfo inflight_info; 402 int log_call_fd; 403 /* Must be held while using backend_fd */ 404 pthread_mutex_t backend_mutex; 405 int backend_fd; 406 uint64_t log_size; 407 uint8_t *log_table; 408 uint64_t features; 409 uint64_t protocol_features; 410 bool broken; 411 uint16_t max_queues; 412 413 /* 414 * @read_msg: custom method to read vhost-user message 415 * 416 * Read data from vhost_user socket fd and fill up 417 * the passed VhostUserMsg *vmsg struct. 418 * 419 * If reading fails, it should close the received set of file 420 * descriptors as socket message's auxiliary data. 421 * 422 * For the details, please refer to vu_message_read in libvhost-user.c 423 * which will be used by default if not custom method is provided when 424 * calling vu_init 425 * 426 * Returns: true if vhost-user message successfully received, 427 * otherwise return false. 428 * 429 */ 430 vu_read_msg_cb read_msg; 431 432 /* 433 * @set_watch: add or update the given fd to the watch set, 434 * call cb when condition is met. 435 */ 436 vu_set_watch_cb set_watch; 437 438 /* @remove_watch: remove the given fd from the watch set */ 439 vu_remove_watch_cb remove_watch; 440 441 /* 442 * @panic: encountered an unrecoverable error, you may try to re-initialize 443 */ 444 vu_panic_cb panic; 445 const VuDevIface *iface; 446 447 /* Postcopy data */ 448 int postcopy_ufd; 449 bool postcopy_listening; 450 }; 451 452 typedef struct VuVirtqElement { 453 unsigned int index; 454 unsigned int out_num; 455 unsigned int in_num; 456 struct iovec *in_sg; 457 struct iovec *out_sg; 458 } VuVirtqElement; 459 460 /** 461 * vu_init: 462 * @dev: a VuDev context 463 * @max_queues: maximum number of virtqueues 464 * @socket: the socket connected to vhost-user frontend 465 * @panic: a panic callback 466 * @set_watch: a set_watch callback 467 * @remove_watch: a remove_watch callback 468 * @iface: a VuDevIface structure with vhost-user device callbacks 469 * 470 * Initializes a VuDev vhost-user context. 471 * 472 * Returns: true on success, false on failure. 473 **/ 474 bool vu_init(VuDev *dev, 475 uint16_t max_queues, 476 int socket, 477 vu_panic_cb panic, 478 vu_read_msg_cb read_msg, 479 vu_set_watch_cb set_watch, 480 vu_remove_watch_cb remove_watch, 481 const VuDevIface *iface); 482 483 484 /** 485 * vu_deinit: 486 * @dev: a VuDev context 487 * 488 * Cleans up the VuDev context 489 */ 490 void vu_deinit(VuDev *dev); 491 492 493 /** 494 * vu_request_to_string: return string for vhost message request 495 * @req: VhostUserMsg request 496 * 497 * Returns a const string, do not free. 498 */ 499 const char *vu_request_to_string(unsigned int req); 500 501 /** 502 * vu_dispatch: 503 * @dev: a VuDev context 504 * 505 * Process one vhost-user message. 506 * 507 * Returns: TRUE on success, FALSE on failure. 508 */ 509 bool vu_dispatch(VuDev *dev); 510 511 /** 512 * vu_gpa_to_va: 513 * @dev: a VuDev context 514 * @plen: guest memory size 515 * @guest_addr: guest address 516 * 517 * Translate a guest address to a pointer. Returns NULL on failure. 518 */ 519 void *vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr); 520 521 /** 522 * vu_get_queue: 523 * @dev: a VuDev context 524 * @qidx: queue index 525 * 526 * Returns the queue number @qidx. 527 */ 528 VuVirtq *vu_get_queue(VuDev *dev, int qidx); 529 530 /** 531 * vu_set_queue_handler: 532 * @dev: a VuDev context 533 * @vq: a VuVirtq queue 534 * @handler: the queue handler callback 535 * 536 * Set the queue handler. This function may be called several times 537 * for the same queue. If called with NULL @handler, the handler is 538 * removed. 539 */ 540 void vu_set_queue_handler(VuDev *dev, VuVirtq *vq, 541 vu_queue_handler_cb handler); 542 543 /** 544 * vu_set_queue_host_notifier: 545 * @dev: a VuDev context 546 * @vq: a VuVirtq queue 547 * @fd: a file descriptor 548 * @size: host page size 549 * @offset: notifier offset in @fd file 550 * 551 * Set queue's host notifier. This function may be called several 552 * times for the same queue. If called with -1 @fd, the notifier 553 * is removed. 554 */ 555 bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd, 556 int size, int offset); 557 558 /** 559 * vu_lookup_shared_object: 560 * @dev: a VuDev context 561 * @uuid: UUID of the shared object 562 * @dmabuf_fd: output dma-buf file descriptor 563 * 564 * Lookup for a virtio shared object (i.e., dma-buf fd) associated with the 565 * received UUID. Result, if found, is stored in the dmabuf_fd argument. 566 * 567 * Returns: whether the virtio object was found. 568 */ 569 bool vu_lookup_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN], 570 int *dmabuf_fd); 571 572 /** 573 * vu_add_shared_object: 574 * @dev: a VuDev context 575 * @uuid: UUID of the shared object 576 * 577 * Registers this back-end as the exporter for the object associated with 578 * the received UUID. 579 * 580 * Returns: TRUE on success, FALSE on failure. 581 */ 582 bool vu_add_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]); 583 584 /** 585 * vu_rm_shared_object: 586 * @dev: a VuDev context 587 * @uuid: UUID of the shared object 588 * 589 * Removes a shared object entry (i.e., back-end entry) associated with the 590 * received UUID key from the hash table. 591 * 592 * Returns: TRUE on success, FALSE on failure. 593 */ 594 bool vu_rm_shared_object(VuDev *dev, unsigned char uuid[UUID_LEN]); 595 596 /** 597 * vu_queue_set_notification: 598 * @dev: a VuDev context 599 * @vq: a VuVirtq queue 600 * @enable: state 601 * 602 * Set whether the queue notifies (via event index or interrupt) 603 */ 604 void vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable); 605 606 /** 607 * vu_queue_enabled: 608 * @dev: a VuDev context 609 * @vq: a VuVirtq queue 610 * 611 * Returns: whether the queue is enabled. 612 */ 613 bool vu_queue_enabled(VuDev *dev, VuVirtq *vq); 614 615 /** 616 * vu_queue_started: 617 * @dev: a VuDev context 618 * @vq: a VuVirtq queue 619 * 620 * Returns: whether the queue is started. 621 */ 622 bool vu_queue_started(const VuDev *dev, const VuVirtq *vq); 623 624 /** 625 * vu_queue_empty: 626 * @dev: a VuDev context 627 * @vq: a VuVirtq queue 628 * 629 * Returns: true if the queue is empty or not ready. 630 */ 631 bool vu_queue_empty(VuDev *dev, VuVirtq *vq); 632 633 /** 634 * vu_queue_notify: 635 * @dev: a VuDev context 636 * @vq: a VuVirtq queue 637 * 638 * Request to notify the queue via callfd (skipped if unnecessary) 639 */ 640 void vu_queue_notify(VuDev *dev, VuVirtq *vq); 641 642 void vu_config_change_msg(VuDev *dev); 643 644 /** 645 * vu_queue_notify_sync: 646 * @dev: a VuDev context 647 * @vq: a VuVirtq queue 648 * 649 * Request to notify the queue via callfd (skipped if unnecessary) 650 * or sync message if possible. 651 */ 652 void vu_queue_notify_sync(VuDev *dev, VuVirtq *vq); 653 654 /** 655 * vu_queue_pop: 656 * @dev: a VuDev context 657 * @vq: a VuVirtq queue 658 * @sz: the size of struct to return (must be >= VuVirtqElement) 659 * 660 * Returns: a VuVirtqElement filled from the queue or NULL. The 661 * returned element must be free()-d by the caller. 662 */ 663 void *vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz); 664 665 666 /** 667 * vu_queue_unpop: 668 * @dev: a VuDev context 669 * @vq: a VuVirtq queue 670 * @elem: The #VuVirtqElement 671 * @len: number of bytes written 672 * 673 * Pretend the most recent element wasn't popped from the virtqueue. The next 674 * call to vu_queue_pop() will refetch the element. 675 */ 676 void vu_queue_unpop(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem, 677 size_t len); 678 679 /** 680 * vu_queue_rewind: 681 * @dev: a VuDev context 682 * @vq: a VuVirtq queue 683 * @num: number of elements to push back 684 * 685 * Pretend that elements weren't popped from the virtqueue. The next 686 * virtqueue_pop() will refetch the oldest element. 687 * 688 * Returns: true on success, false if @num is greater than the number of in use 689 * elements. 690 */ 691 bool vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num); 692 693 /** 694 * vu_queue_fill: 695 * @dev: a VuDev context 696 * @vq: a VuVirtq queue 697 * @elem: a VuVirtqElement 698 * @len: length in bytes to write 699 * @idx: optional offset for the used ring index (0 in general) 700 * 701 * Fill the used ring with @elem element. 702 */ 703 void vu_queue_fill(VuDev *dev, VuVirtq *vq, 704 const VuVirtqElement *elem, 705 unsigned int len, unsigned int idx); 706 707 /** 708 * vu_queue_push: 709 * @dev: a VuDev context 710 * @vq: a VuVirtq queue 711 * @elem: a VuVirtqElement 712 * @len: length in bytes to write 713 * 714 * Helper that combines vu_queue_fill() with a vu_queue_flush(). 715 */ 716 void vu_queue_push(VuDev *dev, VuVirtq *vq, 717 const VuVirtqElement *elem, unsigned int len); 718 719 /** 720 * vu_queue_flush: 721 * @dev: a VuDev context 722 * @vq: a VuVirtq queue 723 * @num: number of elements to flush 724 * 725 * Mark the last number of elements as done (used.idx is updated by 726 * num elements). 727 */ 728 void vu_queue_flush(VuDev *dev, VuVirtq *vq, unsigned int num); 729 730 /** 731 * vu_queue_get_avail_bytes: 732 * @dev: a VuDev context 733 * @vq: a VuVirtq queue 734 * @in_bytes: in bytes 735 * @out_bytes: out bytes 736 * @max_in_bytes: stop counting after max_in_bytes 737 * @max_out_bytes: stop counting after max_out_bytes 738 * 739 * Count the number of available bytes, up to max_in_bytes/max_out_bytes. 740 */ 741 void vu_queue_get_avail_bytes(VuDev *vdev, VuVirtq *vq, unsigned int *in_bytes, 742 unsigned int *out_bytes, 743 unsigned max_in_bytes, unsigned max_out_bytes); 744 745 /** 746 * vu_queue_avail_bytes: 747 * @dev: a VuDev context 748 * @vq: a VuVirtq queue 749 * @in_bytes: expected in bytes 750 * @out_bytes: expected out bytes 751 * 752 * Returns: true if in_bytes <= in_total && out_bytes <= out_total 753 */ 754 bool vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes, 755 unsigned int out_bytes); 756 757 #endif /* LIBVHOST_USER_H */ 758