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 = (struct vring_packed_desc *)(uintptr_t)
 167                 vhost_iova_to_vva(dev, vq, vq->ring_addrs.desc_user_addr,
 168                                 &size, VHOST_ACCESS_RW);
 169         if (!vq->desc_packed || size != req_size)
 170                 return -1;
 171
 172         req_size = sizeof(struct vring_packed_desc_event);
 173         size = req_size;
 174         vq->driver_event = (struct vring_packed_desc_event *)(uintptr_t)
 175                 vhost_iova_to_vva(dev, vq, vq->ring_addrs.avail_user_addr,
 176                                 &size, VHOST_ACCESS_RW);
 177         if (!vq->driver_event || size != req_size)
 178                 return -1;
 179
 180         req_size = sizeof(struct vring_packed_desc_event);
 181         size = req_size;
 182         vq->device_event = (struct vring_packed_desc_event *)(uintptr_t)
 183                 vhost_iova_to_vva(dev, vq, vq->ring_addrs.used_user_addr,
 184                                 &size, VHOST_ACCESS_RW);
 185         if (!vq->device_event || size != req_size)
 186                 return -1;
 187
 188         return 0;
 189 }
 190
 191 int
 192 vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 193 {
 194
 195         if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 196                 goto out;
 197
 198         if (vq_is_packed(dev)) {
 199                 if (vring_translate_packed(dev, vq) < 0)
 200                         return -1;
 201         } else {
 202                 if (vring_translate_split(dev, vq) < 0)
 203                         return -1;
 204         }
 205 out:
 206         vq->access_ok = 1;
 207
 208         return 0;
 209 }
 210
 211 void
 212 vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 213 {
 214         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 215                 vhost_user_iotlb_wr_lock(vq);
 216
 217         vq->access_ok = 0;
 218         vq->desc = NULL;
 219         vq->avail = NULL;
 220         vq->used = NULL;
 221
 222         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 223                 vhost_user_iotlb_wr_unlock(vq);
 224 }
 225
 226 static void
 227 init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 228 {
 229         struct vhost_virtqueue *vq;
 230
 231         if (vring_idx >= VHOST_MAX_VRING) {
 232                 RTE_LOG(ERR, VHOST_CONFIG,
 233                                 "Failed not init vring, out of bound (%d)\n",
 234                                 vring_idx);
 235                 return;
 236         }
 237
 238         vq = dev->virtqueue[vring_idx];
 239
 240         memset(vq, 0, sizeof(struct vhost_virtqueue));
 241
 242         vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
 243         vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
 244
 245         vhost_user_iotlb_init(dev, vring_idx);
 246         /* Backends are set to -1 indicating an inactive device. */
 247         vq->backend = -1;
 248
 249         TAILQ_INIT(&vq->zmbuf_list);
 250 }
 251
 252 static void
 253 reset_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 254 {
 255         struct vhost_virtqueue *vq;
 256         int callfd;
 257
 258         if (vring_idx >= VHOST_MAX_VRING) {
 259                 RTE_LOG(ERR, VHOST_CONFIG,
 260                                 "Failed not init vring, out of bound (%d)\n",
 261                                 vring_idx);
 262                 return;
 263         }
 264
 265         vq = dev->virtqueue[vring_idx];
 266         callfd = vq->callfd;
 267         init_vring_queue(dev, vring_idx);
 268         vq->callfd = callfd;
 269 }
 270
 271 int
 272 alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 273 {
 274         struct vhost_virtqueue *vq;
 275
 276         vq = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
 277         if (vq == NULL) {
 278                 RTE_LOG(ERR, VHOST_CONFIG,
 279                         "Failed to allocate memory for vring:%u.\n", vring_idx);
 280                 return -1;
 281         }
 282
 283         dev->virtqueue[vring_idx] = vq;
 284         init_vring_queue(dev, vring_idx);
 285         rte_spinlock_init(&vq->access_lock);
 286         vq->avail_wrap_counter = 1;
 287         vq->used_wrap_counter = 1;
 288         vq->signalled_used_valid = false;
 289
 290         dev->nr_vring += 1;
 291
 292         return 0;
 293 }
 294
 295 /*
 296  * Reset some variables in device structure, while keeping few
 297  * others untouched, such as vid, ifname, nr_vring: they
 298  * should be same unless the device is removed.
 299  */
 300 void
 301 reset_device(struct virtio_net *dev)
 302 {
 303         uint32_t i;
 304
 305         dev->features = 0;
 306         dev->protocol_features = 0;
 307         dev->flags &= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 308
 309         for (i = 0; i < dev->nr_vring; i++)
 310                 reset_vring_queue(dev, i);
 311 }
 312
 313 /*
 314  * Invoked when there is a new vhost-user connection established (when
 315  * there is a new virtio device being attached).
 316  */
 317 int
 318 vhost_new_device(void)
 319 {
 320         struct virtio_net *dev;
 321         int i;
 322
 323         for (i = 0; i < MAX_VHOST_DEVICE; i++) {
 324                 if (vhost_devices[i] == NULL)
 325                         break;
 326         }
 327
 328         if (i == MAX_VHOST_DEVICE) {
 329                 RTE_LOG(ERR, VHOST_CONFIG,
 330                         "Failed to find a free slot for new device.\n");
 331                 return -1;
 332         }
 333
 334         dev = rte_zmalloc(NULL, sizeof(struct virtio_net), 0);
 335         if (dev == NULL) {
 336                 RTE_LOG(ERR, VHOST_CONFIG,
 337                         "Failed to allocate memory for new dev.\n");
 338                 return -1;
 339         }
 340
 341         vhost_devices[i] = dev;
 342         dev->vid = i;
 343         dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 344         dev->slave_req_fd = -1;
 345         dev->vdpa_dev_id = -1;
 346         rte_spinlock_init(&dev->slave_req_lock);
 347
 348         return i;
 349 }
 350
 351 void
 352 vhost_destroy_device_notify(struct virtio_net *dev)
 353 {
 354         struct rte_vdpa_device *vdpa_dev;
 355         int did;
 356
 357         if (dev->flags & VIRTIO_DEV_RUNNING) {
 358                 did = dev->vdpa_dev_id;
 359                 vdpa_dev = rte_vdpa_get_device(did);
 360                 if (vdpa_dev && vdpa_dev->ops->dev_close)
 361                         vdpa_dev->ops->dev_close(dev->vid);
 362                 dev->flags &= ~VIRTIO_DEV_RUNNING;
 363                 dev->notify_ops->destroy_device(dev->vid);
 364         }
 365 }
 366
 367 /*
 368  * Invoked when there is the vhost-user connection is broken (when
 369  * the virtio device is being detached).
 370  */
 371 void
 372 vhost_destroy_device(int vid)
 373 {
 374         struct virtio_net *dev = get_device(vid);
 375
 376         if (dev == NULL)
 377                 return;
 378
 379         vhost_destroy_device_notify(dev);
 380
 381         cleanup_device(dev, 1);
 382         free_device(dev);
 383
 384         vhost_devices[vid] = NULL;
 385 }
 386
 387 void
 388 vhost_attach_vdpa_device(int vid, int did)
 389 {
 390         struct virtio_net *dev = get_device(vid);
 391
 392         if (dev == NULL)
 393                 return;
 394
 395         if (rte_vdpa_get_device(did) == NULL)
 396                 return;
 397
 398         dev->vdpa_dev_id = did;
 399 }
 400
 401 void
 402 vhost_detach_vdpa_device(int vid)
 403 {
 404         struct virtio_net *dev = get_device(vid);
 405
 406         if (dev == NULL)
 407                 return;
 408
 409         vhost_user_host_notifier_ctrl(vid, false);
 410
 411         dev->vdpa_dev_id = -1;
 412 }
 413
 414 void
 415 vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
 416 {
 417         struct virtio_net *dev;
 418         unsigned int len;
 419
 420         dev = get_device(vid);
 421         if (dev == NULL)
 422                 return;
 423
 424         len = if_len > sizeof(dev->ifname) ?
 425                 sizeof(dev->ifname) : if_len;
 426
 427         strncpy(dev->ifname, if_name, len);
 428         dev->ifname[sizeof(dev->ifname) - 1] = '\0';
 429 }
 430
 431 void
 432 vhost_enable_dequeue_zero_copy(int vid)
 433 {
 434         struct virtio_net *dev = get_device(vid);
 435
 436         if (dev == NULL)
 437                 return;
 438
 439         dev->dequeue_zero_copy = 1;
 440 }
 441
 442 void
 443 vhost_set_builtin_virtio_net(int vid, bool enable)
 444 {
 445         struct virtio_net *dev = get_device(vid);
 446
 447         if (dev == NULL)
 448                 return;
 449
 450         if (enable)
 451                 dev->flags |= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 452         else
 453                 dev->flags &= ~VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 454 }
 455
 456 int
 457 rte_vhost_get_mtu(int vid, uint16_t *mtu)
 458 {
 459         struct virtio_net *dev = get_device(vid);
 460
 461         if (!dev)
 462                 return -ENODEV;
 463
 464         if (!(dev->flags & VIRTIO_DEV_READY))
 465                 return -EAGAIN;
 466
 467         if (!(dev->features & (1ULL << VIRTIO_NET_F_MTU)))
 468                 return -ENOTSUP;
 469
 470         *mtu = dev->mtu;
 471
 472         return 0;
 473 }
 474
 475 int
 476 rte_vhost_get_numa_node(int vid)
 477 {
 478 #ifdef RTE_LIBRTE_VHOST_NUMA
 479         struct virtio_net *dev = get_device(vid);
 480         int numa_node;
 481         int ret;
 482
 483         if (dev == NULL)
 484                 return -1;
 485
 486         ret = get_mempolicy(&numa_node, NULL, 0, dev,
 487                             MPOL_F_NODE | MPOL_F_ADDR);
 488         if (ret < 0) {
 489                 RTE_LOG(ERR, VHOST_CONFIG,
 490                         "(%d) failed to query numa node: %s\n",
 491                         vid, rte_strerror(errno));
 492                 return -1;
 493         }
 494
 495         return numa_node;
 496 #else
 497         RTE_SET_USED(vid);
 498         return -1;
 499 #endif
 500 }
 501
 502 uint32_t
 503 rte_vhost_get_queue_num(int vid)
 504 {
 505         struct virtio_net *dev = get_device(vid);
 506
 507         if (dev == NULL)
 508                 return 0;
 509
 510         return dev->nr_vring / 2;
 511 }
 512
 513 uint16_t
 514 rte_vhost_get_vring_num(int vid)
 515 {
 516         struct virtio_net *dev = get_device(vid);
 517
 518         if (dev == NULL)
 519                 return 0;
 520
 521         return dev->nr_vring;
 522 }
 523
 524 int
 525 rte_vhost_get_ifname(int vid, char *buf, size_t len)
 526 {
 527         struct virtio_net *dev = get_device(vid);
 528
 529         if (dev == NULL)
 530                 return -1;
 531
 532         len = RTE_MIN(len, sizeof(dev->ifname));
 533
 534         strncpy(buf, dev->ifname, len);
 535         buf[len - 1] = '\0';
 536
 537         return 0;
 538 }
 539
 540 int
 541 rte_vhost_get_negotiated_features(int vid, uint64_t *features)
 542 {
 543         struct virtio_net *dev;
 544
 545         dev = get_device(vid);
 546         if (!dev)
 547                 return -1;
 548
 549         *features = dev->features;
 550         return 0;
 551 }
 552
 553 int
 554 rte_vhost_get_mem_table(int vid, struct rte_vhost_memory **mem)
 555 {
 556         struct virtio_net *dev;
 557         struct rte_vhost_memory *m;
 558         size_t size;
 559
 560         dev = get_device(vid);
 561         if (!dev)
 562                 return -1;
 563
 564         size = dev->mem->nregions * sizeof(struct rte_vhost_mem_region);
 565         m = malloc(sizeof(struct rte_vhost_memory) + size);
 566         if (!m)
 567                 return -1;
 568
 569         m->nregions = dev->mem->nregions;
 570         memcpy(m->regions, dev->mem->regions, size);
 571         *mem = m;
 572
 573         return 0;
 574 }
 575
 576 int
 577 rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
 578                           struct rte_vhost_vring *vring)
 579 {
 580         struct virtio_net *dev;
 581         struct vhost_virtqueue *vq;
 582
 583         dev = get_device(vid);
 584         if (!dev)
 585                 return -1;
 586
 587         if (vring_idx >= VHOST_MAX_VRING)
 588                 return -1;
 589
 590         vq = dev->virtqueue[vring_idx];
 591         if (!vq)
 592                 return -1;
 593
 594         vring->desc  = vq->desc;
 595         vring->avail = vq->avail;
 596         vring->used  = vq->used;
 597         vring->log_guest_addr  = vq->log_guest_addr;
 598
 599         vring->callfd  = vq->callfd;
 600         vring->kickfd  = vq->kickfd;
 601         vring->size    = vq->size;
 602
 603         return 0;
 604 }
 605
 606 int
 607 rte_vhost_vring_call(int vid, uint16_t vring_idx)
 608 {
 609         struct virtio_net *dev;
 610         struct vhost_virtqueue *vq;
 611
 612         dev = get_device(vid);
 613         if (!dev)
 614                 return -1;
 615
 616         if (vring_idx >= VHOST_MAX_VRING)
 617                 return -1;
 618
 619         vq = dev->virtqueue[vring_idx];
 620         if (!vq)
 621                 return -1;
 622
 623         if (vq_is_packed(dev))
 624                 vhost_vring_call_packed(dev, vq);
 625         else
 626                 vhost_vring_call_split(dev, vq);
 627
 628         return 0;
 629 }
 630
 631 uint16_t
 632 rte_vhost_avail_entries(int vid, uint16_t queue_id)
 633 {
 634         struct virtio_net *dev;
 635         struct vhost_virtqueue *vq;
 636
 637         dev = get_device(vid);
 638         if (!dev)
 639                 return 0;
 640
 641         vq = dev->virtqueue[queue_id];
 642         if (!vq->enabled)
 643                 return 0;
 644
 645         return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx;
 646 }
 647
 648 static inline void
 649 vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
 650 {
 651         if (enable)
 652                 vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
 653         else
 654                 vq->used->flags |= VRING_USED_F_NO_NOTIFY;
 655 }
 656
 657 static inline void
 658 vhost_enable_notify_packed(struct virtio_net *dev,
 659                 struct vhost_virtqueue *vq, int enable)
 660 {
 661         uint16_t flags;
 662
 663         if (!enable)
 664                 vq->device_event->flags = VRING_EVENT_F_DISABLE;
 665
 666         flags = VRING_EVENT_F_ENABLE;
 667         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
 668                 flags = VRING_EVENT_F_DESC;
 669                 vq->device_event->off_wrap = vq->last_avail_idx |
 670                         vq->avail_wrap_counter << 15;
 671         }
 672
 673         rte_smp_wmb();
 674
 675         vq->device_event->flags = flags;
 676 }
 677
 678 int
 679 rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
 680 {
 681         struct virtio_net *dev = get_device(vid);
 682         struct vhost_virtqueue *vq;
 683
 684         if (!dev)
 685                 return -1;
 686
 687         vq = dev->virtqueue[queue_id];
 688
 689         if (vq_is_packed(dev))
 690                 vhost_enable_notify_packed(dev, vq, enable);
 691         else
 692                 vhost_enable_notify_split(vq, enable);
 693
 694         return 0;
 695 }
 696
 697 void
 698 rte_vhost_log_write(int vid, uint64_t addr, uint64_t len)
 699 {
 700         struct virtio_net *dev = get_device(vid);
 701
 702         if (dev == NULL)
 703                 return;
 704
 705         vhost_log_write(dev, addr, len);
 706 }
 707
 708 void
 709 rte_vhost_log_used_vring(int vid, uint16_t vring_idx,
 710                          uint64_t offset, uint64_t len)
 711 {
 712         struct virtio_net *dev;
 713         struct vhost_virtqueue *vq;
 714
 715         dev = get_device(vid);
 716         if (dev == NULL)
 717                 return;
 718
 719         if (vring_idx >= VHOST_MAX_VRING)
 720                 return;
 721         vq = dev->virtqueue[vring_idx];
 722         if (!vq)
 723                 return;
 724
 725         vhost_log_used_vring(dev, vq, offset, len);
 726 }
 727
 728 uint32_t
 729 rte_vhost_rx_queue_count(int vid, uint16_t qid)
 730 {
 731         struct virtio_net *dev;
 732         struct vhost_virtqueue *vq;
 733
 734         dev = get_device(vid);
 735         if (dev == NULL)
 736                 return 0;
 737
 738         if (unlikely(qid >= dev->nr_vring || (qid & 1) == 0)) {
 739                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 740                         dev->vid, __func__, qid);
 741                 return 0;
 742         }
 743
 744         vq = dev->virtqueue[qid];
 745         if (vq == NULL)
 746                 return 0;
 747
 748         if (unlikely(vq->enabled == 0 || vq->avail == NULL))
 749                 return 0;
 750
 751         return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
 752 }
 753
 754 int rte_vhost_get_vdpa_device_id(int vid)
 755 {
 756         struct virtio_net *dev = get_device(vid);
 757
 758         if (dev == NULL)
 759                 return -1;
 760
 761         return dev->vdpa_dev_id;
 762 }
 763
 764 int rte_vhost_get_log_base(int vid, uint64_t *log_base,
 765                 uint64_t *log_size)
 766 {
 767         struct virtio_net *dev = get_device(vid);
 768
 769         if (!dev)
 770                 return -1;
 771
 772         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 773                 RTE_LOG(ERR, VHOST_DATA,
 774                         "(%d) %s: built-in vhost net backend is disabled.\n",
 775                         dev->vid, __func__);
 776                 return -1;
 777         }
 778
 779         *log_base = dev->log_base;
 780         *log_size = dev->log_size;
 781
 782         return 0;
 783 }
 784
 785 int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
 786                 uint16_t *last_avail_idx, uint16_t *last_used_idx)
 787 {
 788         struct virtio_net *dev = get_device(vid);
 789
 790         if (!dev)
 791                 return -1;
 792
 793         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 794                 RTE_LOG(ERR, VHOST_DATA,
 795                         "(%d) %s: built-in vhost net backend is disabled.\n",
 796                         dev->vid, __func__);
 797                 return -1;
 798         }
 799
 800         *last_avail_idx = dev->virtqueue[queue_id]->last_avail_idx;
 801         *last_used_idx = dev->virtqueue[queue_id]->last_used_idx;
 802
 803         return 0;
 804 }
 805
 806 int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
 807                 uint16_t last_avail_idx, uint16_t last_used_idx)
 808 {
 809         struct virtio_net *dev = get_device(vid);
 810
 811         if (!dev)
 812                 return -1;
 813
 814         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 815                 RTE_LOG(ERR, VHOST_DATA,
 816                         "(%d) %s: built-in vhost net backend is disabled.\n",
 817                         dev->vid, __func__);
 818                 return -1;
 819         }
 820
 821         dev->virtqueue[queue_id]->last_avail_idx = last_avail_idx;
 822         dev->virtqueue[queue_id]->last_used_idx = last_used_idx;
 823
 824         return 0;
 825 }