lib/librte_vhost/vhost.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2017 Intel Corporation
   3  */
   4
   5 #include <linux/vhost.h>
   6 #include <linux/virtio_net.h>
   7 #include <stddef.h>
   8 #include <stdint.h>
   9 #include <stdlib.h>
  10 #ifdef RTE_LIBRTE_VHOST_NUMA
  11 #include <numaif.h>
  12 #endif
  13
  14 #include <rte_errno.h>
  15 #include <rte_ethdev.h>
  16 #include <rte_log.h>
  17 #include <rte_string_fns.h>
  18 #include <rte_memory.h>
  19 #include <rte_malloc.h>
  20 #include <rte_vhost.h>
  21 #include <rte_rwlock.h>
  22
  23 #include "iotlb.h"
  24 #include "vhost.h"
  25 #include "vhost_user.h"
  26
  27 struct virtio_net *vhost_devices[MAX_VHOST_DEVICE];
  28
  29 /* Called with iotlb_lock read-locked */
  30 uint64_t
  31 __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
  32                     uint64_t iova, uint64_t *size, uint8_t perm)
  33 {
  34         uint64_t vva, tmp_size;
  35
  36         if (unlikely(!*size))
  37                 return 0;
  38
  39         tmp_size = *size;
  40
  41         vva = vhost_user_iotlb_cache_find(vq, iova, &tmp_size, perm);
  42         if (tmp_size == *size)
  43                 return vva;
  44
  45         iova += tmp_size;
  46
  47         if (!vhost_user_iotlb_pending_miss(vq, iova, perm)) {
  48                 /*
  49                  * iotlb_lock is read-locked for a full burst,
  50                  * but it only protects the iotlb cache.
  51                  * In case of IOTLB miss, we might block on the socket,
  52                  * which could cause a deadlock with QEMU if an IOTLB update
  53                  * is being handled. We can safely unlock here to avoid it.
  54                  */
  55                 vhost_user_iotlb_rd_unlock(vq);
  56
  57                 vhost_user_iotlb_pending_insert(vq, iova, perm);
  58                 if (vhost_user_iotlb_miss(dev, iova, perm)) {
  59                         RTE_LOG(ERR, VHOST_CONFIG,
  60                                 "IOTLB miss req failed for IOVA 0x%" PRIx64 "\n",
  61                                 iova);
  62                         vhost_user_iotlb_pending_remove(vq, iova, 1, perm);
  63                 }
  64
  65                 vhost_user_iotlb_rd_lock(vq);
  66         }
  67
  68         return 0;
  69 }
  70
  71 void
  72 cleanup_vq(struct vhost_virtqueue *vq, int destroy)
  73 {
  74         if ((vq->callfd >= 0) && (destroy != 0))
  75                 close(vq->callfd);
  76         if (vq->kickfd >= 0)
  77                 close(vq->kickfd);
  78 }
  79
  80 /*
  81  * Unmap any memory, close any file descriptors and
  82  * free any memory owned by a device.
  83  */
  84 void
  85 cleanup_device(struct virtio_net *dev, int destroy)
  86 {
  87         uint32_t i;
  88
  89         vhost_backend_cleanup(dev);
  90
  91         for (i = 0; i < dev->nr_vring; i++)
  92                 cleanup_vq(dev->virtqueue[i], destroy);
  93 }
  94
  95 void
  96 free_vq(struct virtio_net *dev, struct vhost_virtqueue *vq)
  97 {
  98         if (vq_is_packed(dev))
  99                 rte_free(vq->shadow_used_packed);
 100         else
 101                 rte_free(vq->shadow_used_split);
 102         rte_free(vq->batch_copy_elems);
 103         rte_mempool_free(vq->iotlb_pool);
 104         rte_free(vq);
 105 }
 106
 107 /*
 108  * Release virtqueues and device memory.
 109  */
 110 static void
 111 free_device(struct virtio_net *dev)
 112 {
 113         uint32_t i;
 114
 115         for (i = 0; i < dev->nr_vring; i++)
 116                 free_vq(dev, dev->virtqueue[i]);
 117
 118         rte_free(dev);
 119 }
 120
 121 static int
 122 vring_translate_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 123 {
 124         uint64_t req_size, size;
 125
 126         req_size = sizeof(struct vring_desc) * vq->size;
 127         size = req_size;
 128         vq->desc = (struct vring_desc *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 129                                                 vq->ring_addrs.desc_user_addr,
 130                                                 &size, VHOST_ACCESS_RW);
 131         if (!vq->desc || size != req_size)
 132                 return -1;
 133
 134         req_size = sizeof(struct vring_avail);
 135         req_size += sizeof(uint16_t) * vq->size;
 136         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
 137                 req_size += sizeof(uint16_t);
 138         size = req_size;
 139         vq->avail = (struct vring_avail *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 140                                                 vq->ring_addrs.avail_user_addr,
 141                                                 &size, VHOST_ACCESS_RW);
 142         if (!vq->avail || size != req_size)
 143                 return -1;
 144
 145         req_size = sizeof(struct vring_used);
 146         req_size += sizeof(struct vring_used_elem) * vq->size;
 147         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
 148                 req_size += sizeof(uint16_t);
 149         size = req_size;
 150         vq->used = (struct vring_used *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 151                                                 vq->ring_addrs.used_user_addr,
 152                                                 &size, VHOST_ACCESS_RW);
 153         if (!vq->used || size != req_size)
 154                 return -1;
 155
 156         return 0;
 157 }
 158
 159 static int
 160 vring_translate_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
 161 {
 162         uint64_t req_size, size;
 163
 164         req_size = sizeof(struct vring_packed_desc) * vq->size;
 165         size = req_size;
 166         vq->desc_packed =
 167                 (struct vring_packed_desc *)(uintptr_t)vhost_iova_to_vva(dev,
 168                                         vq, vq->ring_addrs.desc_user_addr,
 169                                         &size, VHOST_ACCESS_RW);
 170         if (!vq->desc_packed || size != req_size)
 171                 return -1;
 172
 173         return 0;
 174 }
 175
 176 int
 177 vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 178 {
 179
 180         if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 181                 goto out;
 182
 183         if (vq_is_packed(dev)) {
 184                 if (vring_translate_packed(dev, vq) < 0)
 185                         return -1;
 186         } else {
 187                 if (vring_translate_split(dev, vq) < 0)
 188                         return -1;
 189         }
 190 out:
 191         vq->access_ok = 1;
 192
 193         return 0;
 194 }
 195
 196 void
 197 vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 198 {
 199         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 200                 vhost_user_iotlb_wr_lock(vq);
 201
 202         vq->access_ok = 0;
 203         vq->desc = NULL;
 204         vq->avail = NULL;
 205         vq->used = NULL;
 206
 207         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 208                 vhost_user_iotlb_wr_unlock(vq);
 209 }
 210
 211 static void
 212 init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 213 {
 214         struct vhost_virtqueue *vq;
 215
 216         if (vring_idx >= VHOST_MAX_VRING) {
 217                 RTE_LOG(ERR, VHOST_CONFIG,
 218                                 "Failed not init vring, out of bound (%d)\n",
 219                                 vring_idx);
 220                 return;
 221         }
 222
 223         vq = dev->virtqueue[vring_idx];
 224
 225         memset(vq, 0, sizeof(struct vhost_virtqueue));
 226
 227         vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
 228         vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
 229
 230         vhost_user_iotlb_init(dev, vring_idx);
 231         /* Backends are set to -1 indicating an inactive device. */
 232         vq->backend = -1;
 233
 234         TAILQ_INIT(&vq->zmbuf_list);
 235 }
 236
 237 static void
 238 reset_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 239 {
 240         struct vhost_virtqueue *vq;
 241         int callfd;
 242
 243         if (vring_idx >= VHOST_MAX_VRING) {
 244                 RTE_LOG(ERR, VHOST_CONFIG,
 245                                 "Failed not init vring, out of bound (%d)\n",
 246                                 vring_idx);
 247                 return;
 248         }
 249
 250         vq = dev->virtqueue[vring_idx];
 251         callfd = vq->callfd;
 252         init_vring_queue(dev, vring_idx);
 253         vq->callfd = callfd;
 254 }
 255
 256 int
 257 alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 258 {
 259         struct vhost_virtqueue *vq;
 260
 261         vq = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
 262         if (vq == NULL) {
 263                 RTE_LOG(ERR, VHOST_CONFIG,
 264                         "Failed to allocate memory for vring:%u.\n", vring_idx);
 265                 return -1;
 266         }
 267
 268         dev->virtqueue[vring_idx] = vq;
 269         init_vring_queue(dev, vring_idx);
 270         rte_spinlock_init(&vq->access_lock);
 271         vq->avail_wrap_counter = 1;
 272         vq->used_wrap_counter = 1;
 273
 274         dev->nr_vring += 1;
 275
 276         return 0;
 277 }
 278
 279 /*
 280  * Reset some variables in device structure, while keeping few
 281  * others untouched, such as vid, ifname, nr_vring: they
 282  * should be same unless the device is removed.
 283  */
 284 void
 285 reset_device(struct virtio_net *dev)
 286 {
 287         uint32_t i;
 288
 289         dev->features = 0;
 290         dev->protocol_features = 0;
 291         dev->flags &= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 292
 293         for (i = 0; i < dev->nr_vring; i++)
 294                 reset_vring_queue(dev, i);
 295 }
 296
 297 /*
 298  * Invoked when there is a new vhost-user connection established (when
 299  * there is a new virtio device being attached).
 300  */
 301 int
 302 vhost_new_device(void)
 303 {
 304         struct virtio_net *dev;
 305         int i;
 306
 307         for (i = 0; i < MAX_VHOST_DEVICE; i++) {
 308                 if (vhost_devices[i] == NULL)
 309                         break;
 310         }
 311
 312         if (i == MAX_VHOST_DEVICE) {
 313                 RTE_LOG(ERR, VHOST_CONFIG,
 314                         "Failed to find a free slot for new device.\n");
 315                 return -1;
 316         }
 317
 318         dev = rte_zmalloc(NULL, sizeof(struct virtio_net), 0);
 319         if (dev == NULL) {
 320                 RTE_LOG(ERR, VHOST_CONFIG,
 321                         "Failed to allocate memory for new dev.\n");
 322                 return -1;
 323         }
 324
 325         vhost_devices[i] = dev;
 326         dev->vid = i;
 327         dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 328         dev->slave_req_fd = -1;
 329         dev->vdpa_dev_id = -1;
 330         rte_spinlock_init(&dev->slave_req_lock);
 331
 332         return i;
 333 }
 334
 335 void
 336 vhost_destroy_device_notify(struct virtio_net *dev)
 337 {
 338         struct rte_vdpa_device *vdpa_dev;
 339         int did;
 340
 341         if (dev->flags & VIRTIO_DEV_RUNNING) {
 342                 did = dev->vdpa_dev_id;
 343                 vdpa_dev = rte_vdpa_get_device(did);
 344                 if (vdpa_dev && vdpa_dev->ops->dev_close)
 345                         vdpa_dev->ops->dev_close(dev->vid);
 346                 dev->flags &= ~VIRTIO_DEV_RUNNING;
 347                 dev->notify_ops->destroy_device(dev->vid);
 348         }
 349 }
 350
 351 /*
 352  * Invoked when there is the vhost-user connection is broken (when
 353  * the virtio device is being detached).
 354  */
 355 void
 356 vhost_destroy_device(int vid)
 357 {
 358         struct virtio_net *dev = get_device(vid);
 359
 360         if (dev == NULL)
 361                 return;
 362
 363         vhost_destroy_device_notify(dev);
 364
 365         cleanup_device(dev, 1);
 366         free_device(dev);
 367
 368         vhost_devices[vid] = NULL;
 369 }
 370
 371 void
 372 vhost_attach_vdpa_device(int vid, int did)
 373 {
 374         struct virtio_net *dev = get_device(vid);
 375
 376         if (dev == NULL)
 377                 return;
 378
 379         if (rte_vdpa_get_device(did) == NULL)
 380                 return;
 381
 382         dev->vdpa_dev_id = did;
 383 }
 384
 385 void
 386 vhost_detach_vdpa_device(int vid)
 387 {
 388         struct virtio_net *dev = get_device(vid);
 389
 390         if (dev == NULL)
 391                 return;
 392
 393         vhost_user_host_notifier_ctrl(vid, false);
 394
 395         dev->vdpa_dev_id = -1;
 396 }
 397
 398 void
 399 vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
 400 {
 401         struct virtio_net *dev;
 402         unsigned int len;
 403
 404         dev = get_device(vid);
 405         if (dev == NULL)
 406                 return;
 407
 408         len = if_len > sizeof(dev->ifname) ?
 409                 sizeof(dev->ifname) : if_len;
 410
 411         strncpy(dev->ifname, if_name, len);
 412         dev->ifname[sizeof(dev->ifname) - 1] = '\0';
 413 }
 414
 415 void
 416 vhost_enable_dequeue_zero_copy(int vid)
 417 {
 418         struct virtio_net *dev = get_device(vid);
 419
 420         if (dev == NULL)
 421                 return;
 422
 423         dev->dequeue_zero_copy = 1;
 424 }
 425
 426 void
 427 vhost_set_builtin_virtio_net(int vid, bool enable)
 428 {
 429         struct virtio_net *dev = get_device(vid);
 430
 431         if (dev == NULL)
 432                 return;
 433
 434         if (enable)
 435                 dev->flags |= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 436         else
 437                 dev->flags &= ~VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 438 }
 439
 440 int
 441 rte_vhost_get_mtu(int vid, uint16_t *mtu)
 442 {
 443         struct virtio_net *dev = get_device(vid);
 444
 445         if (!dev)
 446                 return -ENODEV;
 447
 448         if (!(dev->flags & VIRTIO_DEV_READY))
 449                 return -EAGAIN;
 450
 451         if (!(dev->features & (1ULL << VIRTIO_NET_F_MTU)))
 452                 return -ENOTSUP;
 453
 454         *mtu = dev->mtu;
 455
 456         return 0;
 457 }
 458
 459 int
 460 rte_vhost_get_numa_node(int vid)
 461 {
 462 #ifdef RTE_LIBRTE_VHOST_NUMA
 463         struct virtio_net *dev = get_device(vid);
 464         int numa_node;
 465         int ret;
 466
 467         if (dev == NULL)
 468                 return -1;
 469
 470         ret = get_mempolicy(&numa_node, NULL, 0, dev,
 471                             MPOL_F_NODE | MPOL_F_ADDR);
 472         if (ret < 0) {
 473                 RTE_LOG(ERR, VHOST_CONFIG,
 474                         "(%d) failed to query numa node: %s\n",
 475                         vid, rte_strerror(errno));
 476                 return -1;
 477         }
 478
 479         return numa_node;
 480 #else
 481         RTE_SET_USED(vid);
 482         return -1;
 483 #endif
 484 }
 485
 486 uint32_t
 487 rte_vhost_get_queue_num(int vid)
 488 {
 489         struct virtio_net *dev = get_device(vid);
 490
 491         if (dev == NULL)
 492                 return 0;
 493
 494         return dev->nr_vring / 2;
 495 }
 496
 497 uint16_t
 498 rte_vhost_get_vring_num(int vid)
 499 {
 500         struct virtio_net *dev = get_device(vid);
 501
 502         if (dev == NULL)
 503                 return 0;
 504
 505         return dev->nr_vring;
 506 }
 507
 508 int
 509 rte_vhost_get_ifname(int vid, char *buf, size_t len)
 510 {
 511         struct virtio_net *dev = get_device(vid);
 512
 513         if (dev == NULL)
 514                 return -1;
 515
 516         len = RTE_MIN(len, sizeof(dev->ifname));
 517
 518         strncpy(buf, dev->ifname, len);
 519         buf[len - 1] = '\0';
 520
 521         return 0;
 522 }
 523
 524 int
 525 rte_vhost_get_negotiated_features(int vid, uint64_t *features)
 526 {
 527         struct virtio_net *dev;
 528
 529         dev = get_device(vid);
 530         if (!dev)
 531                 return -1;
 532
 533         *features = dev->features;
 534         return 0;
 535 }
 536
 537 int
 538 rte_vhost_get_mem_table(int vid, struct rte_vhost_memory **mem)
 539 {
 540         struct virtio_net *dev;
 541         struct rte_vhost_memory *m;
 542         size_t size;
 543
 544         dev = get_device(vid);
 545         if (!dev)
 546                 return -1;
 547
 548         size = dev->mem->nregions * sizeof(struct rte_vhost_mem_region);
 549         m = malloc(sizeof(struct rte_vhost_memory) + size);
 550         if (!m)
 551                 return -1;
 552
 553         m->nregions = dev->mem->nregions;
 554         memcpy(m->regions, dev->mem->regions, size);
 555         *mem = m;
 556
 557         return 0;
 558 }
 559
 560 int
 561 rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
 562                           struct rte_vhost_vring *vring)
 563 {
 564         struct virtio_net *dev;
 565         struct vhost_virtqueue *vq;
 566
 567         dev = get_device(vid);
 568         if (!dev)
 569                 return -1;
 570
 571         if (vring_idx >= VHOST_MAX_VRING)
 572                 return -1;
 573
 574         vq = dev->virtqueue[vring_idx];
 575         if (!vq)
 576                 return -1;
 577
 578         vring->desc  = vq->desc;
 579         vring->avail = vq->avail;
 580         vring->used  = vq->used;
 581         vring->log_guest_addr  = vq->log_guest_addr;
 582
 583         vring->callfd  = vq->callfd;
 584         vring->kickfd  = vq->kickfd;
 585         vring->size    = vq->size;
 586
 587         return 0;
 588 }
 589
 590 int
 591 rte_vhost_vring_call(int vid, uint16_t vring_idx)
 592 {
 593         struct virtio_net *dev;
 594         struct vhost_virtqueue *vq;
 595
 596         dev = get_device(vid);
 597         if (!dev)
 598                 return -1;
 599
 600         if (vring_idx >= VHOST_MAX_VRING)
 601                 return -1;
 602
 603         vq = dev->virtqueue[vring_idx];
 604         if (!vq)
 605                 return -1;
 606
 607         vhost_vring_call(dev, vq);
 608         return 0;
 609 }
 610
 611 uint16_t
 612 rte_vhost_avail_entries(int vid, uint16_t queue_id)
 613 {
 614         struct virtio_net *dev;
 615         struct vhost_virtqueue *vq;
 616
 617         dev = get_device(vid);
 618         if (!dev)
 619                 return 0;
 620
 621         vq = dev->virtqueue[queue_id];
 622         if (!vq->enabled)
 623                 return 0;
 624
 625         return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx;
 626 }
 627
 628 int
 629 rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
 630 {
 631         struct virtio_net *dev = get_device(vid);
 632
 633         if (!dev)
 634                 return -1;
 635
 636         if (enable)
 637                 dev->virtqueue[queue_id]->used->flags &=
 638                         ~VRING_USED_F_NO_NOTIFY;
 639         else
 640                 dev->virtqueue[queue_id]->used->flags |= VRING_USED_F_NO_NOTIFY;
 641         return 0;
 642 }
 643
 644 void
 645 rte_vhost_log_write(int vid, uint64_t addr, uint64_t len)
 646 {
 647         struct virtio_net *dev = get_device(vid);
 648
 649         if (dev == NULL)
 650                 return;
 651
 652         vhost_log_write(dev, addr, len);
 653 }
 654
 655 void
 656 rte_vhost_log_used_vring(int vid, uint16_t vring_idx,
 657                          uint64_t offset, uint64_t len)
 658 {
 659         struct virtio_net *dev;
 660         struct vhost_virtqueue *vq;
 661
 662         dev = get_device(vid);
 663         if (dev == NULL)
 664                 return;
 665
 666         if (vring_idx >= VHOST_MAX_VRING)
 667                 return;
 668         vq = dev->virtqueue[vring_idx];
 669         if (!vq)
 670                 return;
 671
 672         vhost_log_used_vring(dev, vq, offset, len);
 673 }
 674
 675 uint32_t
 676 rte_vhost_rx_queue_count(int vid, uint16_t qid)
 677 {
 678         struct virtio_net *dev;
 679         struct vhost_virtqueue *vq;
 680
 681         dev = get_device(vid);
 682         if (dev == NULL)
 683                 return 0;
 684
 685         if (unlikely(qid >= dev->nr_vring || (qid & 1) == 0)) {
 686                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 687                         dev->vid, __func__, qid);
 688                 return 0;
 689         }
 690
 691         vq = dev->virtqueue[qid];
 692         if (vq == NULL)
 693                 return 0;
 694
 695         if (unlikely(vq->enabled == 0 || vq->avail == NULL))
 696                 return 0;
 697
 698         return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
 699 }
 700
 701 int rte_vhost_get_vdpa_device_id(int vid)
 702 {
 703         struct virtio_net *dev = get_device(vid);
 704
 705         if (dev == NULL)
 706                 return -1;
 707
 708         return dev->vdpa_dev_id;
 709 }
 710
 711 int rte_vhost_get_log_base(int vid, uint64_t *log_base,
 712                 uint64_t *log_size)
 713 {
 714         struct virtio_net *dev = get_device(vid);
 715
 716         if (!dev)
 717                 return -1;
 718
 719         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 720                 RTE_LOG(ERR, VHOST_DATA,
 721                         "(%d) %s: built-in vhost net backend is disabled.\n",
 722                         dev->vid, __func__);
 723                 return -1;
 724         }
 725
 726         *log_base = dev->log_base;
 727         *log_size = dev->log_size;
 728
 729         return 0;
 730 }
 731
 732 int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
 733                 uint16_t *last_avail_idx, uint16_t *last_used_idx)
 734 {
 735         struct virtio_net *dev = get_device(vid);
 736
 737         if (!dev)
 738                 return -1;
 739
 740         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 741                 RTE_LOG(ERR, VHOST_DATA,
 742                         "(%d) %s: built-in vhost net backend is disabled.\n",
 743                         dev->vid, __func__);
 744                 return -1;
 745         }
 746
 747         *last_avail_idx = dev->virtqueue[queue_id]->last_avail_idx;
 748         *last_used_idx = dev->virtqueue[queue_id]->last_used_idx;
 749
 750         return 0;
 751 }
 752
 753 int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
 754                 uint16_t last_avail_idx, uint16_t last_used_idx)
 755 {
 756         struct virtio_net *dev = get_device(vid);
 757
 758         if (!dev)
 759                 return -1;
 760
 761         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 762                 RTE_LOG(ERR, VHOST_DATA,
 763                         "(%d) %s: built-in vhost net backend is disabled.\n",
 764                         dev->vid, __func__);
 765                 return -1;
 766         }
 767
 768         dev->virtqueue[queue_id]->last_avail_idx = last_avail_idx;
 769         dev->virtqueue[queue_id]->last_used_idx = last_used_idx;
 770
 771         return 0;
 772 }