libvhost-user.h (19406B)
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 * Set a reasonable maximum number of ram slots, which will be supported by 35 * any architecture. 36 */ 37 #define VHOST_USER_MAX_RAM_SLOTS 32 38 39 #define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64) 40 41 typedef enum VhostSetConfigType { 42 VHOST_SET_CONFIG_TYPE_MASTER = 0, 43 VHOST_SET_CONFIG_TYPE_MIGRATION = 1, 44 } VhostSetConfigType; 45 46 /* 47 * Maximum size of virtio device config space 48 */ 49 #define VHOST_USER_MAX_CONFIG_SIZE 256 50 51 enum VhostUserProtocolFeature { 52 VHOST_USER_PROTOCOL_F_MQ = 0, 53 VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1, 54 VHOST_USER_PROTOCOL_F_RARP = 2, 55 VHOST_USER_PROTOCOL_F_REPLY_ACK = 3, 56 VHOST_USER_PROTOCOL_F_NET_MTU = 4, 57 VHOST_USER_PROTOCOL_F_SLAVE_REQ = 5, 58 VHOST_USER_PROTOCOL_F_CROSS_ENDIAN = 6, 59 VHOST_USER_PROTOCOL_F_CRYPTO_SESSION = 7, 60 VHOST_USER_PROTOCOL_F_PAGEFAULT = 8, 61 VHOST_USER_PROTOCOL_F_CONFIG = 9, 62 VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10, 63 VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11, 64 VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12, 65 VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS = 14, 66 VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS = 15, 67 68 VHOST_USER_PROTOCOL_F_MAX 69 }; 70 71 #define VHOST_USER_PROTOCOL_FEATURE_MASK ((1 << VHOST_USER_PROTOCOL_F_MAX) - 1) 72 73 typedef enum VhostUserRequest { 74 VHOST_USER_NONE = 0, 75 VHOST_USER_GET_FEATURES = 1, 76 VHOST_USER_SET_FEATURES = 2, 77 VHOST_USER_SET_OWNER = 3, 78 VHOST_USER_RESET_OWNER = 4, 79 VHOST_USER_SET_MEM_TABLE = 5, 80 VHOST_USER_SET_LOG_BASE = 6, 81 VHOST_USER_SET_LOG_FD = 7, 82 VHOST_USER_SET_VRING_NUM = 8, 83 VHOST_USER_SET_VRING_ADDR = 9, 84 VHOST_USER_SET_VRING_BASE = 10, 85 VHOST_USER_GET_VRING_BASE = 11, 86 VHOST_USER_SET_VRING_KICK = 12, 87 VHOST_USER_SET_VRING_CALL = 13, 88 VHOST_USER_SET_VRING_ERR = 14, 89 VHOST_USER_GET_PROTOCOL_FEATURES = 15, 90 VHOST_USER_SET_PROTOCOL_FEATURES = 16, 91 VHOST_USER_GET_QUEUE_NUM = 17, 92 VHOST_USER_SET_VRING_ENABLE = 18, 93 VHOST_USER_SEND_RARP = 19, 94 VHOST_USER_NET_SET_MTU = 20, 95 VHOST_USER_SET_SLAVE_REQ_FD = 21, 96 VHOST_USER_IOTLB_MSG = 22, 97 VHOST_USER_SET_VRING_ENDIAN = 23, 98 VHOST_USER_GET_CONFIG = 24, 99 VHOST_USER_SET_CONFIG = 25, 100 VHOST_USER_CREATE_CRYPTO_SESSION = 26, 101 VHOST_USER_CLOSE_CRYPTO_SESSION = 27, 102 VHOST_USER_POSTCOPY_ADVISE = 28, 103 VHOST_USER_POSTCOPY_LISTEN = 29, 104 VHOST_USER_POSTCOPY_END = 30, 105 VHOST_USER_GET_INFLIGHT_FD = 31, 106 VHOST_USER_SET_INFLIGHT_FD = 32, 107 VHOST_USER_GPU_SET_SOCKET = 33, 108 VHOST_USER_VRING_KICK = 35, 109 VHOST_USER_GET_MAX_MEM_SLOTS = 36, 110 VHOST_USER_ADD_MEM_REG = 37, 111 VHOST_USER_REM_MEM_REG = 38, 112 VHOST_USER_MAX 113 } VhostUserRequest; 114 115 typedef enum VhostUserSlaveRequest { 116 VHOST_USER_SLAVE_NONE = 0, 117 VHOST_USER_SLAVE_IOTLB_MSG = 1, 118 VHOST_USER_SLAVE_CONFIG_CHANGE_MSG = 2, 119 VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG = 3, 120 VHOST_USER_SLAVE_VRING_CALL = 4, 121 VHOST_USER_SLAVE_VRING_ERR = 5, 122 VHOST_USER_SLAVE_MAX 123 } VhostUserSlaveRequest; 124 125 typedef struct VhostUserMemoryRegion { 126 uint64_t guest_phys_addr; 127 uint64_t memory_size; 128 uint64_t userspace_addr; 129 uint64_t mmap_offset; 130 } VhostUserMemoryRegion; 131 132 #define VHOST_USER_MEM_REG_SIZE (sizeof(VhostUserMemoryRegion)) 133 134 typedef struct VhostUserMemory { 135 uint32_t nregions; 136 uint32_t padding; 137 VhostUserMemoryRegion regions[VHOST_MEMORY_BASELINE_NREGIONS]; 138 } VhostUserMemory; 139 140 typedef struct VhostUserMemRegMsg { 141 uint64_t padding; 142 VhostUserMemoryRegion region; 143 } VhostUserMemRegMsg; 144 145 typedef struct VhostUserLog { 146 uint64_t mmap_size; 147 uint64_t mmap_offset; 148 } VhostUserLog; 149 150 typedef struct VhostUserConfig { 151 uint32_t offset; 152 uint32_t size; 153 uint32_t flags; 154 uint8_t region[VHOST_USER_MAX_CONFIG_SIZE]; 155 } VhostUserConfig; 156 157 static VhostUserConfig c __attribute__ ((unused)); 158 #define VHOST_USER_CONFIG_HDR_SIZE (sizeof(c.offset) \ 159 + sizeof(c.size) \ 160 + sizeof(c.flags)) 161 162 typedef struct VhostUserVringArea { 163 uint64_t u64; 164 uint64_t size; 165 uint64_t offset; 166 } VhostUserVringArea; 167 168 typedef struct VhostUserInflight { 169 uint64_t mmap_size; 170 uint64_t mmap_offset; 171 uint16_t num_queues; 172 uint16_t queue_size; 173 } VhostUserInflight; 174 175 #if defined(_WIN32) && (defined(__x86_64__) || defined(__i386__)) 176 # define VU_PACKED __attribute__((gcc_struct, packed)) 177 #else 178 # define VU_PACKED __attribute__((packed)) 179 #endif 180 181 typedef struct VhostUserMsg { 182 int request; 183 184 #define VHOST_USER_VERSION_MASK (0x3) 185 #define VHOST_USER_REPLY_MASK (0x1 << 2) 186 #define VHOST_USER_NEED_REPLY_MASK (0x1 << 3) 187 uint32_t flags; 188 uint32_t size; /* the following payload size */ 189 190 union { 191 #define VHOST_USER_VRING_IDX_MASK (0xff) 192 #define VHOST_USER_VRING_NOFD_MASK (0x1 << 8) 193 uint64_t u64; 194 struct vhost_vring_state state; 195 struct vhost_vring_addr addr; 196 VhostUserMemory memory; 197 VhostUserMemRegMsg memreg; 198 VhostUserLog log; 199 VhostUserConfig config; 200 VhostUserVringArea area; 201 VhostUserInflight inflight; 202 } payload; 203 204 int fds[VHOST_MEMORY_BASELINE_NREGIONS]; 205 int fd_num; 206 uint8_t *data; 207 } VU_PACKED VhostUserMsg; 208 209 typedef struct VuDevRegion { 210 /* Guest Physical address. */ 211 uint64_t gpa; 212 /* Memory region size. */ 213 uint64_t size; 214 /* QEMU virtual address (userspace). */ 215 uint64_t qva; 216 /* Starting offset in our mmaped space. */ 217 uint64_t mmap_offset; 218 /* Start address of mmaped space. */ 219 uint64_t mmap_addr; 220 } VuDevRegion; 221 222 typedef struct VuDev VuDev; 223 224 typedef uint64_t (*vu_get_features_cb) (VuDev *dev); 225 typedef void (*vu_set_features_cb) (VuDev *dev, uint64_t features); 226 typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg, 227 int *do_reply); 228 typedef bool (*vu_read_msg_cb) (VuDev *dev, int sock, VhostUserMsg *vmsg); 229 typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool started); 230 typedef bool (*vu_queue_is_processed_in_order_cb) (VuDev *dev, int qidx); 231 typedef int (*vu_get_config_cb) (VuDev *dev, uint8_t *config, uint32_t len); 232 typedef int (*vu_set_config_cb) (VuDev *dev, const uint8_t *data, 233 uint32_t offset, uint32_t size, 234 uint32_t flags); 235 236 typedef struct VuDevIface { 237 /* called by VHOST_USER_GET_FEATURES to get the features bitmask */ 238 vu_get_features_cb get_features; 239 /* enable vhost implementation features */ 240 vu_set_features_cb set_features; 241 /* get the protocol feature bitmask from the underlying vhost 242 * implementation */ 243 vu_get_features_cb get_protocol_features; 244 /* enable protocol features in the underlying vhost implementation. */ 245 vu_set_features_cb set_protocol_features; 246 /* process_msg is called for each vhost-user message received */ 247 /* skip libvhost-user processing if return value != 0 */ 248 vu_process_msg_cb process_msg; 249 /* tells when queues can be processed */ 250 vu_queue_set_started_cb queue_set_started; 251 /* 252 * If the queue is processed in order, in which case it will be 253 * resumed to vring.used->idx. This can help to support resuming 254 * on unmanaged exit/crash. 255 */ 256 vu_queue_is_processed_in_order_cb queue_is_processed_in_order; 257 /* get the config space of the device */ 258 vu_get_config_cb get_config; 259 /* set the config space of the device */ 260 vu_set_config_cb set_config; 261 } VuDevIface; 262 263 typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx); 264 265 typedef struct VuRing { 266 unsigned int num; 267 struct vring_desc *desc; 268 struct vring_avail *avail; 269 struct vring_used *used; 270 uint64_t log_guest_addr; 271 uint32_t flags; 272 } VuRing; 273 274 typedef struct VuDescStateSplit { 275 /* Indicate whether this descriptor is inflight or not. 276 * Only available for head-descriptor. */ 277 uint8_t inflight; 278 279 /* Padding */ 280 uint8_t padding[5]; 281 282 /* Maintain a list for the last batch of used descriptors. 283 * Only available when batching is used for submitting */ 284 uint16_t next; 285 286 /* Used to preserve the order of fetching available descriptors. 287 * Only available for head-descriptor. */ 288 uint64_t counter; 289 } VuDescStateSplit; 290 291 typedef struct VuVirtqInflight { 292 /* The feature flags of this region. Now it's initialized to 0. */ 293 uint64_t features; 294 295 /* The version of this region. It's 1 currently. 296 * Zero value indicates a vm reset happened. */ 297 uint16_t version; 298 299 /* The size of VuDescStateSplit array. It's equal to the virtqueue 300 * size. Slave could get it from queue size field of VhostUserInflight. */ 301 uint16_t desc_num; 302 303 /* The head of list that track the last batch of used descriptors. */ 304 uint16_t last_batch_head; 305 306 /* Storing the idx value of used ring */ 307 uint16_t used_idx; 308 309 /* Used to track the state of each descriptor in descriptor table */ 310 VuDescStateSplit desc[]; 311 } VuVirtqInflight; 312 313 typedef struct VuVirtqInflightDesc { 314 uint16_t index; 315 uint64_t counter; 316 } VuVirtqInflightDesc; 317 318 typedef struct VuVirtq { 319 VuRing vring; 320 321 VuVirtqInflight *inflight; 322 323 VuVirtqInflightDesc *resubmit_list; 324 325 uint16_t resubmit_num; 326 327 uint64_t counter; 328 329 /* Next head to pop */ 330 uint16_t last_avail_idx; 331 332 /* Last avail_idx read from VQ. */ 333 uint16_t shadow_avail_idx; 334 335 uint16_t used_idx; 336 337 /* Last used index value we have signalled on */ 338 uint16_t signalled_used; 339 340 /* Last used index value we have signalled on */ 341 bool signalled_used_valid; 342 343 /* Notification enabled? */ 344 bool notification; 345 346 int inuse; 347 348 vu_queue_handler_cb handler; 349 350 int call_fd; 351 int kick_fd; 352 int err_fd; 353 unsigned int enable; 354 bool started; 355 356 /* Guest addresses of our ring */ 357 struct vhost_vring_addr vra; 358 } VuVirtq; 359 360 enum VuWatchCondtion { 361 VU_WATCH_IN = POLLIN, 362 VU_WATCH_OUT = POLLOUT, 363 VU_WATCH_PRI = POLLPRI, 364 VU_WATCH_ERR = POLLERR, 365 VU_WATCH_HUP = POLLHUP, 366 }; 367 368 typedef void (*vu_panic_cb) (VuDev *dev, const char *err); 369 typedef void (*vu_watch_cb) (VuDev *dev, int condition, void *data); 370 typedef void (*vu_set_watch_cb) (VuDev *dev, int fd, int condition, 371 vu_watch_cb cb, void *data); 372 typedef void (*vu_remove_watch_cb) (VuDev *dev, int fd); 373 374 typedef struct VuDevInflightInfo { 375 int fd; 376 void *addr; 377 uint64_t size; 378 } VuDevInflightInfo; 379 380 struct VuDev { 381 int sock; 382 uint32_t nregions; 383 VuDevRegion regions[VHOST_USER_MAX_RAM_SLOTS]; 384 VuVirtq *vq; 385 VuDevInflightInfo inflight_info; 386 int log_call_fd; 387 /* Must be held while using slave_fd */ 388 pthread_mutex_t slave_mutex; 389 int slave_fd; 390 uint64_t log_size; 391 uint8_t *log_table; 392 uint64_t features; 393 uint64_t protocol_features; 394 bool broken; 395 uint16_t max_queues; 396 397 /* 398 * @read_msg: custom method to read vhost-user message 399 * 400 * Read data from vhost_user socket fd and fill up 401 * the passed VhostUserMsg *vmsg struct. 402 * 403 * If reading fails, it should close the received set of file 404 * descriptors as socket message's auxiliary data. 405 * 406 * For the details, please refer to vu_message_read in libvhost-user.c 407 * which will be used by default if not custom method is provided when 408 * calling vu_init 409 * 410 * Returns: true if vhost-user message successfully received, 411 * otherwise return false. 412 * 413 */ 414 vu_read_msg_cb read_msg; 415 416 /* 417 * @set_watch: add or update the given fd to the watch set, 418 * call cb when condition is met. 419 */ 420 vu_set_watch_cb set_watch; 421 422 /* @remove_watch: remove the given fd from the watch set */ 423 vu_remove_watch_cb remove_watch; 424 425 /* 426 * @panic: encountered an unrecoverable error, you may try to re-initialize 427 */ 428 vu_panic_cb panic; 429 const VuDevIface *iface; 430 431 /* Postcopy data */ 432 int postcopy_ufd; 433 bool postcopy_listening; 434 }; 435 436 typedef struct VuVirtqElement { 437 unsigned int index; 438 unsigned int out_num; 439 unsigned int in_num; 440 struct iovec *in_sg; 441 struct iovec *out_sg; 442 } VuVirtqElement; 443 444 /** 445 * vu_init: 446 * @dev: a VuDev context 447 * @max_queues: maximum number of virtqueues 448 * @socket: the socket connected to vhost-user master 449 * @panic: a panic callback 450 * @set_watch: a set_watch callback 451 * @remove_watch: a remove_watch callback 452 * @iface: a VuDevIface structure with vhost-user device callbacks 453 * 454 * Initializes a VuDev vhost-user context. 455 * 456 * Returns: true on success, false on failure. 457 **/ 458 bool vu_init(VuDev *dev, 459 uint16_t max_queues, 460 int socket, 461 vu_panic_cb panic, 462 vu_read_msg_cb read_msg, 463 vu_set_watch_cb set_watch, 464 vu_remove_watch_cb remove_watch, 465 const VuDevIface *iface); 466 467 468 /** 469 * vu_deinit: 470 * @dev: a VuDev context 471 * 472 * Cleans up the VuDev context 473 */ 474 void vu_deinit(VuDev *dev); 475 476 477 /** 478 * vu_request_to_string: return string for vhost message request 479 * @req: VhostUserMsg request 480 * 481 * Returns a const string, do not free. 482 */ 483 const char *vu_request_to_string(unsigned int req); 484 485 /** 486 * vu_dispatch: 487 * @dev: a VuDev context 488 * 489 * Process one vhost-user message. 490 * 491 * Returns: TRUE on success, FALSE on failure. 492 */ 493 bool vu_dispatch(VuDev *dev); 494 495 /** 496 * vu_gpa_to_va: 497 * @dev: a VuDev context 498 * @plen: guest memory size 499 * @guest_addr: guest address 500 * 501 * Translate a guest address to a pointer. Returns NULL on failure. 502 */ 503 void *vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr); 504 505 /** 506 * vu_get_queue: 507 * @dev: a VuDev context 508 * @qidx: queue index 509 * 510 * Returns the queue number @qidx. 511 */ 512 VuVirtq *vu_get_queue(VuDev *dev, int qidx); 513 514 /** 515 * vu_set_queue_handler: 516 * @dev: a VuDev context 517 * @vq: a VuVirtq queue 518 * @handler: the queue handler callback 519 * 520 * Set the queue handler. This function may be called several times 521 * for the same queue. If called with NULL @handler, the handler is 522 * removed. 523 */ 524 void vu_set_queue_handler(VuDev *dev, VuVirtq *vq, 525 vu_queue_handler_cb handler); 526 527 /** 528 * vu_set_queue_host_notifier: 529 * @dev: a VuDev context 530 * @vq: a VuVirtq queue 531 * @fd: a file descriptor 532 * @size: host page size 533 * @offset: notifier offset in @fd file 534 * 535 * Set queue's host notifier. This function may be called several 536 * times for the same queue. If called with -1 @fd, the notifier 537 * is removed. 538 */ 539 bool vu_set_queue_host_notifier(VuDev *dev, VuVirtq *vq, int fd, 540 int size, int offset); 541 542 /** 543 * vu_queue_set_notification: 544 * @dev: a VuDev context 545 * @vq: a VuVirtq queue 546 * @enable: state 547 * 548 * Set whether the queue notifies (via event index or interrupt) 549 */ 550 void vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable); 551 552 /** 553 * vu_queue_enabled: 554 * @dev: a VuDev context 555 * @vq: a VuVirtq queue 556 * 557 * Returns: whether the queue is enabled. 558 */ 559 bool vu_queue_enabled(VuDev *dev, VuVirtq *vq); 560 561 /** 562 * vu_queue_started: 563 * @dev: a VuDev context 564 * @vq: a VuVirtq queue 565 * 566 * Returns: whether the queue is started. 567 */ 568 bool vu_queue_started(const VuDev *dev, const VuVirtq *vq); 569 570 /** 571 * vu_queue_empty: 572 * @dev: a VuDev context 573 * @vq: a VuVirtq queue 574 * 575 * Returns: true if the queue is empty or not ready. 576 */ 577 bool vu_queue_empty(VuDev *dev, VuVirtq *vq); 578 579 /** 580 * vu_queue_notify: 581 * @dev: a VuDev context 582 * @vq: a VuVirtq queue 583 * 584 * Request to notify the queue via callfd (skipped if unnecessary) 585 */ 586 void vu_queue_notify(VuDev *dev, VuVirtq *vq); 587 588 /** 589 * vu_queue_notify_sync: 590 * @dev: a VuDev context 591 * @vq: a VuVirtq queue 592 * 593 * Request to notify the queue via callfd (skipped if unnecessary) 594 * or sync message if possible. 595 */ 596 void vu_queue_notify_sync(VuDev *dev, VuVirtq *vq); 597 598 /** 599 * vu_queue_pop: 600 * @dev: a VuDev context 601 * @vq: a VuVirtq queue 602 * @sz: the size of struct to return (must be >= VuVirtqElement) 603 * 604 * Returns: a VuVirtqElement filled from the queue or NULL. The 605 * returned element must be free()-d by the caller. 606 */ 607 void *vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz); 608 609 610 /** 611 * vu_queue_unpop: 612 * @dev: a VuDev context 613 * @vq: a VuVirtq queue 614 * @elem: The #VuVirtqElement 615 * @len: number of bytes written 616 * 617 * Pretend the most recent element wasn't popped from the virtqueue. The next 618 * call to vu_queue_pop() will refetch the element. 619 */ 620 void vu_queue_unpop(VuDev *dev, VuVirtq *vq, VuVirtqElement *elem, 621 size_t len); 622 623 /** 624 * vu_queue_rewind: 625 * @dev: a VuDev context 626 * @vq: a VuVirtq queue 627 * @num: number of elements to push back 628 * 629 * Pretend that elements weren't popped from the virtqueue. The next 630 * virtqueue_pop() will refetch the oldest element. 631 * 632 * Returns: true on success, false if @num is greater than the number of in use 633 * elements. 634 */ 635 bool vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num); 636 637 /** 638 * vu_queue_fill: 639 * @dev: a VuDev context 640 * @vq: a VuVirtq queue 641 * @elem: a VuVirtqElement 642 * @len: length in bytes to write 643 * @idx: optional offset for the used ring index (0 in general) 644 * 645 * Fill the used ring with @elem element. 646 */ 647 void vu_queue_fill(VuDev *dev, VuVirtq *vq, 648 const VuVirtqElement *elem, 649 unsigned int len, unsigned int idx); 650 651 /** 652 * vu_queue_push: 653 * @dev: a VuDev context 654 * @vq: a VuVirtq queue 655 * @elem: a VuVirtqElement 656 * @len: length in bytes to write 657 * 658 * Helper that combines vu_queue_fill() with a vu_queue_flush(). 659 */ 660 void vu_queue_push(VuDev *dev, VuVirtq *vq, 661 const VuVirtqElement *elem, unsigned int len); 662 663 /** 664 * vu_queue_flush: 665 * @dev: a VuDev context 666 * @vq: a VuVirtq queue 667 * @num: number of elements to flush 668 * 669 * Mark the last number of elements as done (used.idx is updated by 670 * num elements). 671 */ 672 void vu_queue_flush(VuDev *dev, VuVirtq *vq, unsigned int num); 673 674 /** 675 * vu_queue_get_avail_bytes: 676 * @dev: a VuDev context 677 * @vq: a VuVirtq queue 678 * @in_bytes: in bytes 679 * @out_bytes: out bytes 680 * @max_in_bytes: stop counting after max_in_bytes 681 * @max_out_bytes: stop counting after max_out_bytes 682 * 683 * Count the number of available bytes, up to max_in_bytes/max_out_bytes. 684 */ 685 void vu_queue_get_avail_bytes(VuDev *vdev, VuVirtq *vq, unsigned int *in_bytes, 686 unsigned int *out_bytes, 687 unsigned max_in_bytes, unsigned max_out_bytes); 688 689 /** 690 * vu_queue_avail_bytes: 691 * @dev: a VuDev context 692 * @vq: a VuVirtq queue 693 * @in_bytes: expected in bytes 694 * @out_bytes: expected out bytes 695 * 696 * Returns: true if in_bytes <= in_total && out_bytes <= out_total 697 */ 698 bool vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes, 699 unsigned int out_bytes); 700 701 #endif /* LIBVHOST_USER_H */