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 <numa.h>
  12 #include <numaif.h>
  13 #endif
  14
  15 #include <rte_errno.h>
  16 #include <rte_ethdev.h>
  17 #include <rte_log.h>
  18 #include <rte_string_fns.h>
  19 #include <rte_memory.h>
  20 #include <rte_malloc.h>
  21 #include <rte_vhost.h>
  22 #include <rte_rwlock.h>
  23
  24 #include "iotlb.h"
  25 #include "vhost.h"
  26 #include "vhost_user.h"
  27
  28 struct virtio_net *vhost_devices[MAX_VHOST_DEVICE];
  29
  30 /* Called with iotlb_lock read-locked */
  31 uint64_t
  32 __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
  33                     uint64_t iova, uint64_t *size, uint8_t perm)
  34 {
  35         uint64_t vva, tmp_size;
  36
  37         if (unlikely(!*size))
  38                 return 0;
  39
  40         tmp_size = *size;
  41
  42         vva = vhost_user_iotlb_cache_find(vq, iova, &tmp_size, perm);
  43         if (tmp_size == *size)
  44                 return vva;
  45
  46         iova += tmp_size;
  47
  48         if (!vhost_user_iotlb_pending_miss(vq, iova, perm)) {
  49                 /*
  50                  * iotlb_lock is read-locked for a full burst,
  51                  * but it only protects the iotlb cache.
  52                  * In case of IOTLB miss, we might block on the socket,
  53                  * which could cause a deadlock with QEMU if an IOTLB update
  54                  * is being handled. We can safely unlock here to avoid it.
  55                  */
  56                 vhost_user_iotlb_rd_unlock(vq);
  57
  58                 vhost_user_iotlb_pending_insert(vq, iova, perm);
  59                 if (vhost_user_iotlb_miss(dev, iova, perm)) {
  60                         RTE_LOG(ERR, VHOST_CONFIG,
  61                                 "IOTLB miss req failed for IOVA 0x%" PRIx64 "\n",
  62                                 iova);
  63                         vhost_user_iotlb_pending_remove(vq, iova, 1, perm);
  64                 }
  65
  66                 vhost_user_iotlb_rd_lock(vq);
  67         }
  68
  69         return 0;
  70 }
  71
  72 void
  73 cleanup_vq(struct vhost_virtqueue *vq, int destroy)
  74 {
  75         if ((vq->callfd >= 0) && (destroy != 0))
  76                 close(vq->callfd);
  77         if (vq->kickfd >= 0)
  78                 close(vq->kickfd);
  79 }
  80
  81 /*
  82  * Unmap any memory, close any file descriptors and
  83  * free any memory owned by a device.
  84  */
  85 void
  86 cleanup_device(struct virtio_net *dev, int destroy)
  87 {
  88         uint32_t i;
  89
  90         vhost_backend_cleanup(dev);
  91
  92         for (i = 0; i < dev->nr_vring; i++)
  93                 cleanup_vq(dev->virtqueue[i], destroy);
  94 }
  95
  96 void
  97 free_vq(struct virtio_net *dev, struct vhost_virtqueue *vq)
  98 {
  99         if (vq_is_packed(dev))
 100                 rte_free(vq->shadow_used_packed);
 101         else
 102                 rte_free(vq->shadow_used_split);
 103         rte_free(vq->batch_copy_elems);
 104         rte_mempool_free(vq->iotlb_pool);
 105         rte_free(vq);
 106 }
 107
 108 /*
 109  * Release virtqueues and device memory.
 110  */
 111 static void
 112 free_device(struct virtio_net *dev)
 113 {
 114         uint32_t i;
 115
 116         for (i = 0; i < dev->nr_vring; i++)
 117                 free_vq(dev, dev->virtqueue[i]);
 118
 119         rte_free(dev);
 120 }
 121
 122 static int
 123 vring_translate_split(struct virtio_net *dev, struct vhost_virtqueue *vq)
 124 {
 125         uint64_t req_size, size;
 126
 127         req_size = sizeof(struct vring_desc) * vq->size;
 128         size = req_size;
 129         vq->desc = (struct vring_desc *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 130                                                 vq->ring_addrs.desc_user_addr,
 131                                                 &size, VHOST_ACCESS_RW);
 132         if (!vq->desc || size != req_size)
 133                 return -1;
 134
 135         req_size = sizeof(struct vring_avail);
 136         req_size += sizeof(uint16_t) * vq->size;
 137         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
 138                 req_size += sizeof(uint16_t);
 139         size = req_size;
 140         vq->avail = (struct vring_avail *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 141                                                 vq->ring_addrs.avail_user_addr,
 142                                                 &size, VHOST_ACCESS_RW);
 143         if (!vq->avail || size != req_size)
 144                 return -1;
 145
 146         req_size = sizeof(struct vring_used);
 147         req_size += sizeof(struct vring_used_elem) * vq->size;
 148         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
 149                 req_size += sizeof(uint16_t);
 150         size = req_size;
 151         vq->used = (struct vring_used *)(uintptr_t)vhost_iova_to_vva(dev, vq,
 152                                                 vq->ring_addrs.used_user_addr,
 153                                                 &size, VHOST_ACCESS_RW);
 154         if (!vq->used || size != req_size)
 155                 return -1;
 156
 157         return 0;
 158 }
 159
 160 static int
 161 vring_translate_packed(struct virtio_net *dev, struct vhost_virtqueue *vq)
 162 {
 163         uint64_t req_size, size;
 164
 165         req_size = sizeof(struct vring_packed_desc) * vq->size;
 166         size = req_size;
 167         vq->desc_packed = (struct vring_packed_desc *)(uintptr_t)
 168                 vhost_iova_to_vva(dev, 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         req_size = sizeof(struct vring_packed_desc_event);
 174         size = req_size;
 175         vq->driver_event = (struct vring_packed_desc_event *)(uintptr_t)
 176                 vhost_iova_to_vva(dev, vq, vq->ring_addrs.avail_user_addr,
 177                                 &size, VHOST_ACCESS_RW);
 178         if (!vq->driver_event || size != req_size)
 179                 return -1;
 180
 181         req_size = sizeof(struct vring_packed_desc_event);
 182         size = req_size;
 183         vq->device_event = (struct vring_packed_desc_event *)(uintptr_t)
 184                 vhost_iova_to_vva(dev, vq, vq->ring_addrs.used_user_addr,
 185                                 &size, VHOST_ACCESS_RW);
 186         if (!vq->device_event || size != req_size)
 187                 return -1;
 188
 189         return 0;
 190 }
 191
 192 int
 193 vring_translate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 194 {
 195
 196         if (!(dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)))
 197                 goto out;
 198
 199         if (vq_is_packed(dev)) {
 200                 if (vring_translate_packed(dev, vq) < 0)
 201                         return -1;
 202         } else {
 203                 if (vring_translate_split(dev, vq) < 0)
 204                         return -1;
 205         }
 206 out:
 207         vq->access_ok = 1;
 208
 209         return 0;
 210 }
 211
 212 void
 213 vring_invalidate(struct virtio_net *dev, struct vhost_virtqueue *vq)
 214 {
 215         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 216                 vhost_user_iotlb_wr_lock(vq);
 217
 218         vq->access_ok = 0;
 219         vq->desc = NULL;
 220         vq->avail = NULL;
 221         vq->used = NULL;
 222
 223         if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
 224                 vhost_user_iotlb_wr_unlock(vq);
 225 }
 226
 227 static void
 228 init_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 229 {
 230         struct vhost_virtqueue *vq;
 231
 232         if (vring_idx >= VHOST_MAX_VRING) {
 233                 RTE_LOG(ERR, VHOST_CONFIG,
 234                                 "Failed not init vring, out of bound (%d)\n",
 235                                 vring_idx);
 236                 return;
 237         }
 238
 239         vq = dev->virtqueue[vring_idx];
 240
 241         memset(vq, 0, sizeof(struct vhost_virtqueue));
 242
 243         vq->kickfd = VIRTIO_UNINITIALIZED_EVENTFD;
 244         vq->callfd = VIRTIO_UNINITIALIZED_EVENTFD;
 245
 246         vhost_user_iotlb_init(dev, vring_idx);
 247         /* Backends are set to -1 indicating an inactive device. */
 248         vq->backend = -1;
 249
 250         TAILQ_INIT(&vq->zmbuf_list);
 251 }
 252
 253 static void
 254 reset_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 255 {
 256         struct vhost_virtqueue *vq;
 257         int callfd;
 258
 259         if (vring_idx >= VHOST_MAX_VRING) {
 260                 RTE_LOG(ERR, VHOST_CONFIG,
 261                                 "Failed not init vring, out of bound (%d)\n",
 262                                 vring_idx);
 263                 return;
 264         }
 265
 266         vq = dev->virtqueue[vring_idx];
 267         callfd = vq->callfd;
 268         init_vring_queue(dev, vring_idx);
 269         vq->callfd = callfd;
 270 }
 271
 272 int
 273 alloc_vring_queue(struct virtio_net *dev, uint32_t vring_idx)
 274 {
 275         struct vhost_virtqueue *vq;
 276
 277         vq = rte_malloc(NULL, sizeof(struct vhost_virtqueue), 0);
 278         if (vq == NULL) {
 279                 RTE_LOG(ERR, VHOST_CONFIG,
 280                         "Failed to allocate memory for vring:%u.\n", vring_idx);
 281                 return -1;
 282         }
 283
 284         dev->virtqueue[vring_idx] = vq;
 285         init_vring_queue(dev, vring_idx);
 286         rte_spinlock_init(&vq->access_lock);
 287         vq->avail_wrap_counter = 1;
 288         vq->used_wrap_counter = 1;
 289         vq->signalled_used_valid = false;
 290
 291         dev->nr_vring += 1;
 292
 293         return 0;
 294 }
 295
 296 /*
 297  * Reset some variables in device structure, while keeping few
 298  * others untouched, such as vid, ifname, nr_vring: they
 299  * should be same unless the device is removed.
 300  */
 301 void
 302 reset_device(struct virtio_net *dev)
 303 {
 304         uint32_t i;
 305
 306         dev->features = 0;
 307         dev->protocol_features = 0;
 308         dev->flags &= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 309
 310         for (i = 0; i < dev->nr_vring; i++)
 311                 reset_vring_queue(dev, i);
 312 }
 313
 314 /*
 315  * Invoked when there is a new vhost-user connection established (when
 316  * there is a new virtio device being attached).
 317  */
 318 int
 319 vhost_new_device(void)
 320 {
 321         struct virtio_net *dev;
 322         int i;
 323
 324         for (i = 0; i < MAX_VHOST_DEVICE; i++) {
 325                 if (vhost_devices[i] == NULL)
 326                         break;
 327         }
 328
 329         if (i == MAX_VHOST_DEVICE) {
 330                 RTE_LOG(ERR, VHOST_CONFIG,
 331                         "Failed to find a free slot for new device.\n");
 332                 return -1;
 333         }
 334
 335         dev = rte_zmalloc(NULL, sizeof(struct virtio_net), 0);
 336         if (dev == NULL) {
 337                 RTE_LOG(ERR, VHOST_CONFIG,
 338                         "Failed to allocate memory for new dev.\n");
 339                 return -1;
 340         }
 341
 342         vhost_devices[i] = dev;
 343         dev->vid = i;
 344         dev->flags = VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 345         dev->slave_req_fd = -1;
 346         dev->vdpa_dev_id = -1;
 347         dev->postcopy_ufd = -1;
 348         rte_spinlock_init(&dev->slave_req_lock);
 349
 350         return i;
 351 }
 352
 353 void
 354 vhost_destroy_device_notify(struct virtio_net *dev)
 355 {
 356         struct rte_vdpa_device *vdpa_dev;
 357         int did;
 358
 359         if (dev->flags & VIRTIO_DEV_RUNNING) {
 360                 did = dev->vdpa_dev_id;
 361                 vdpa_dev = rte_vdpa_get_device(did);
 362                 if (vdpa_dev && vdpa_dev->ops->dev_close)
 363                         vdpa_dev->ops->dev_close(dev->vid);
 364                 dev->flags &= ~VIRTIO_DEV_RUNNING;
 365                 dev->notify_ops->destroy_device(dev->vid);
 366         }
 367 }
 368
 369 /*
 370  * Invoked when there is the vhost-user connection is broken (when
 371  * the virtio device is being detached).
 372  */
 373 void
 374 vhost_destroy_device(int vid)
 375 {
 376         struct virtio_net *dev = get_device(vid);
 377
 378         if (dev == NULL)
 379                 return;
 380
 381         vhost_destroy_device_notify(dev);
 382
 383         cleanup_device(dev, 1);
 384         free_device(dev);
 385
 386         vhost_devices[vid] = NULL;
 387 }
 388
 389 void
 390 vhost_attach_vdpa_device(int vid, int did)
 391 {
 392         struct virtio_net *dev = get_device(vid);
 393
 394         if (dev == NULL)
 395                 return;
 396
 397         if (rte_vdpa_get_device(did) == NULL)
 398                 return;
 399
 400         dev->vdpa_dev_id = did;
 401 }
 402
 403 void
 404 vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
 405 {
 406         struct virtio_net *dev;
 407         unsigned int len;
 408
 409         dev = get_device(vid);
 410         if (dev == NULL)
 411                 return;
 412
 413         len = if_len > sizeof(dev->ifname) ?
 414                 sizeof(dev->ifname) : if_len;
 415
 416         strncpy(dev->ifname, if_name, len);
 417         dev->ifname[sizeof(dev->ifname) - 1] = '\0';
 418 }
 419
 420 void
 421 vhost_enable_dequeue_zero_copy(int vid)
 422 {
 423         struct virtio_net *dev = get_device(vid);
 424
 425         if (dev == NULL)
 426                 return;
 427
 428         dev->dequeue_zero_copy = 1;
 429 }
 430
 431 void
 432 vhost_set_builtin_virtio_net(int vid, bool enable)
 433 {
 434         struct virtio_net *dev = get_device(vid);
 435
 436         if (dev == NULL)
 437                 return;
 438
 439         if (enable)
 440                 dev->flags |= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 441         else
 442                 dev->flags &= ~VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 443 }
 444
 445 int
 446 rte_vhost_get_mtu(int vid, uint16_t *mtu)
 447 {
 448         struct virtio_net *dev = get_device(vid);
 449
 450         if (!dev)
 451                 return -ENODEV;
 452
 453         if (!(dev->flags & VIRTIO_DEV_READY))
 454                 return -EAGAIN;
 455
 456         if (!(dev->features & (1ULL << VIRTIO_NET_F_MTU)))
 457                 return -ENOTSUP;
 458
 459         *mtu = dev->mtu;
 460
 461         return 0;
 462 }
 463
 464 int
 465 rte_vhost_get_numa_node(int vid)
 466 {
 467 #ifdef RTE_LIBRTE_VHOST_NUMA
 468         struct virtio_net *dev = get_device(vid);
 469         int numa_node;
 470         int ret;
 471
 472         if (dev == NULL || numa_available() != 0)
 473                 return -1;
 474
 475         ret = get_mempolicy(&numa_node, NULL, 0, dev,
 476                             MPOL_F_NODE | MPOL_F_ADDR);
 477         if (ret < 0) {
 478                 RTE_LOG(ERR, VHOST_CONFIG,
 479                         "(%d) failed to query numa node: %s\n",
 480                         vid, rte_strerror(errno));
 481                 return -1;
 482         }
 483
 484         return numa_node;
 485 #else
 486         RTE_SET_USED(vid);
 487         return -1;
 488 #endif
 489 }
 490
 491 uint32_t
 492 rte_vhost_get_queue_num(int vid)
 493 {
 494         struct virtio_net *dev = get_device(vid);
 495
 496         if (dev == NULL)
 497                 return 0;
 498
 499         return dev->nr_vring / 2;
 500 }
 501
 502 uint16_t
 503 rte_vhost_get_vring_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;
 511 }
 512
 513 int
 514 rte_vhost_get_ifname(int vid, char *buf, size_t len)
 515 {
 516         struct virtio_net *dev = get_device(vid);
 517
 518         if (dev == NULL)
 519                 return -1;
 520
 521         len = RTE_MIN(len, sizeof(dev->ifname));
 522
 523         strncpy(buf, dev->ifname, len);
 524         buf[len - 1] = '\0';
 525
 526         return 0;
 527 }
 528
 529 int
 530 rte_vhost_get_negotiated_features(int vid, uint64_t *features)
 531 {
 532         struct virtio_net *dev;
 533
 534         dev = get_device(vid);
 535         if (!dev)
 536                 return -1;
 537
 538         *features = dev->features;
 539         return 0;
 540 }
 541
 542 int
 543 rte_vhost_get_mem_table(int vid, struct rte_vhost_memory **mem)
 544 {
 545         struct virtio_net *dev;
 546         struct rte_vhost_memory *m;
 547         size_t size;
 548
 549         dev = get_device(vid);
 550         if (!dev)
 551                 return -1;
 552
 553         size = dev->mem->nregions * sizeof(struct rte_vhost_mem_region);
 554         m = malloc(sizeof(struct rte_vhost_memory) + size);
 555         if (!m)
 556                 return -1;
 557
 558         m->nregions = dev->mem->nregions;
 559         memcpy(m->regions, dev->mem->regions, size);
 560         *mem = m;
 561
 562         return 0;
 563 }
 564
 565 int
 566 rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
 567                           struct rte_vhost_vring *vring)
 568 {
 569         struct virtio_net *dev;
 570         struct vhost_virtqueue *vq;
 571
 572         dev = get_device(vid);
 573         if (!dev)
 574                 return -1;
 575
 576         if (vring_idx >= VHOST_MAX_VRING)
 577                 return -1;
 578
 579         vq = dev->virtqueue[vring_idx];
 580         if (!vq)
 581                 return -1;
 582
 583         vring->desc  = vq->desc;
 584         vring->avail = vq->avail;
 585         vring->used  = vq->used;
 586         vring->log_guest_addr  = vq->log_guest_addr;
 587
 588         vring->callfd  = vq->callfd;
 589         vring->kickfd  = vq->kickfd;
 590         vring->size    = vq->size;
 591
 592         return 0;
 593 }
 594
 595 int
 596 rte_vhost_vring_call(int vid, uint16_t vring_idx)
 597 {
 598         struct virtio_net *dev;
 599         struct vhost_virtqueue *vq;
 600
 601         dev = get_device(vid);
 602         if (!dev)
 603                 return -1;
 604
 605         if (vring_idx >= VHOST_MAX_VRING)
 606                 return -1;
 607
 608         vq = dev->virtqueue[vring_idx];
 609         if (!vq)
 610                 return -1;
 611
 612         if (vq_is_packed(dev))
 613                 vhost_vring_call_packed(dev, vq);
 614         else
 615                 vhost_vring_call_split(dev, vq);
 616
 617         return 0;
 618 }
 619
 620 uint16_t
 621 rte_vhost_avail_entries(int vid, uint16_t queue_id)
 622 {
 623         struct virtio_net *dev;
 624         struct vhost_virtqueue *vq;
 625
 626         dev = get_device(vid);
 627         if (!dev)
 628                 return 0;
 629
 630         vq = dev->virtqueue[queue_id];
 631         if (!vq->enabled)
 632                 return 0;
 633
 634         return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx;
 635 }
 636
 637 static inline void
 638 vhost_enable_notify_split(struct virtio_net *dev,
 639                 struct vhost_virtqueue *vq, int enable)
 640 {
 641         if (!(dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))) {
 642                 if (enable)
 643                         vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
 644                 else
 645                         vq->used->flags |= VRING_USED_F_NO_NOTIFY;
 646         } else {
 647                 if (enable)
 648                         vhost_avail_event(vq) = vq->last_avail_idx;
 649         }
 650 }
 651
 652 static inline void
 653 vhost_enable_notify_packed(struct virtio_net *dev,
 654                 struct vhost_virtqueue *vq, int enable)
 655 {
 656         uint16_t flags;
 657
 658         if (!enable) {
 659                 vq->device_event->flags = VRING_EVENT_F_DISABLE;
 660                 return;
 661         }
 662
 663         flags = VRING_EVENT_F_ENABLE;
 664         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
 665                 flags = VRING_EVENT_F_DESC;
 666                 vq->device_event->off_wrap = vq->last_avail_idx |
 667                         vq->avail_wrap_counter << 15;
 668         }
 669
 670         rte_smp_wmb();
 671
 672         vq->device_event->flags = flags;
 673 }
 674
 675 int
 676 rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
 677 {
 678         struct virtio_net *dev = get_device(vid);
 679         struct vhost_virtqueue *vq;
 680
 681         if (!dev)
 682                 return -1;
 683
 684         vq = dev->virtqueue[queue_id];
 685
 686         if (vq_is_packed(dev))
 687                 vhost_enable_notify_packed(dev, vq, enable);
 688         else
 689                 vhost_enable_notify_split(dev, vq, enable);
 690
 691         return 0;
 692 }
 693
 694 void
 695 rte_vhost_log_write(int vid, uint64_t addr, uint64_t len)
 696 {
 697         struct virtio_net *dev = get_device(vid);
 698
 699         if (dev == NULL)
 700                 return;
 701
 702         vhost_log_write(dev, addr, len);
 703 }
 704
 705 void
 706 rte_vhost_log_used_vring(int vid, uint16_t vring_idx,
 707                          uint64_t offset, uint64_t len)
 708 {
 709         struct virtio_net *dev;
 710         struct vhost_virtqueue *vq;
 711
 712         dev = get_device(vid);
 713         if (dev == NULL)
 714                 return;
 715
 716         if (vring_idx >= VHOST_MAX_VRING)
 717                 return;
 718         vq = dev->virtqueue[vring_idx];
 719         if (!vq)
 720                 return;
 721
 722         vhost_log_used_vring(dev, vq, offset, len);
 723 }
 724
 725 uint32_t
 726 rte_vhost_rx_queue_count(int vid, uint16_t qid)
 727 {
 728         struct virtio_net *dev;
 729         struct vhost_virtqueue *vq;
 730
 731         dev = get_device(vid);
 732         if (dev == NULL)
 733                 return 0;
 734
 735         if (unlikely(qid >= dev->nr_vring || (qid & 1) == 0)) {
 736                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 737                         dev->vid, __func__, qid);
 738                 return 0;
 739         }
 740
 741         vq = dev->virtqueue[qid];
 742         if (vq == NULL)
 743                 return 0;
 744
 745         if (unlikely(vq->enabled == 0 || vq->avail == NULL))
 746                 return 0;
 747
 748         return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
 749 }
 750
 751 int rte_vhost_get_vdpa_device_id(int vid)
 752 {
 753         struct virtio_net *dev = get_device(vid);
 754
 755         if (dev == NULL)
 756                 return -1;
 757
 758         return dev->vdpa_dev_id;
 759 }
 760
 761 int rte_vhost_get_log_base(int vid, uint64_t *log_base,
 762                 uint64_t *log_size)
 763 {
 764         struct virtio_net *dev = get_device(vid);
 765
 766         if (!dev)
 767                 return -1;
 768
 769         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 770                 RTE_LOG(ERR, VHOST_DATA,
 771                         "(%d) %s: built-in vhost net backend is disabled.\n",
 772                         dev->vid, __func__);
 773                 return -1;
 774         }
 775
 776         *log_base = dev->log_base;
 777         *log_size = dev->log_size;
 778
 779         return 0;
 780 }
 781
 782 int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
 783                 uint16_t *last_avail_idx, uint16_t *last_used_idx)
 784 {
 785         struct virtio_net *dev = get_device(vid);
 786
 787         if (!dev)
 788                 return -1;
 789
 790         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 791                 RTE_LOG(ERR, VHOST_DATA,
 792                         "(%d) %s: built-in vhost net backend is disabled.\n",
 793                         dev->vid, __func__);
 794                 return -1;
 795         }
 796
 797         *last_avail_idx = dev->virtqueue[queue_id]->last_avail_idx;
 798         *last_used_idx = dev->virtqueue[queue_id]->last_used_idx;
 799
 800         return 0;
 801 }
 802
 803 int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
 804                 uint16_t last_avail_idx, uint16_t last_used_idx)
 805 {
 806         struct virtio_net *dev = get_device(vid);
 807
 808         if (!dev)
 809                 return -1;
 810
 811         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 812                 RTE_LOG(ERR, VHOST_DATA,
 813                         "(%d) %s: built-in vhost net backend is disabled.\n",
 814                         dev->vid, __func__);
 815                 return -1;
 816         }
 817
 818         dev->virtqueue[queue_id]->last_avail_idx = last_avail_idx;
 819         dev->virtqueue[queue_id]->last_used_idx = last_used_idx;
 820
 821         return 0;
 822 }