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         rte_spinlock_init(&dev->slave_req_lock);
 348
 349         return i;
 350 }
 351
 352 void
 353 vhost_destroy_device_notify(struct virtio_net *dev)
 354 {
 355         struct rte_vdpa_device *vdpa_dev;
 356         int did;
 357
 358         if (dev->flags & VIRTIO_DEV_RUNNING) {
 359                 did = dev->vdpa_dev_id;
 360                 vdpa_dev = rte_vdpa_get_device(did);
 361                 if (vdpa_dev && vdpa_dev->ops->dev_close)
 362                         vdpa_dev->ops->dev_close(dev->vid);
 363                 dev->flags &= ~VIRTIO_DEV_RUNNING;
 364                 dev->notify_ops->destroy_device(dev->vid);
 365         }
 366 }
 367
 368 /*
 369  * Invoked when there is the vhost-user connection is broken (when
 370  * the virtio device is being detached).
 371  */
 372 void
 373 vhost_destroy_device(int vid)
 374 {
 375         struct virtio_net *dev = get_device(vid);
 376
 377         if (dev == NULL)
 378                 return;
 379
 380         vhost_destroy_device_notify(dev);
 381
 382         cleanup_device(dev, 1);
 383         free_device(dev);
 384
 385         vhost_devices[vid] = NULL;
 386 }
 387
 388 void
 389 vhost_attach_vdpa_device(int vid, int did)
 390 {
 391         struct virtio_net *dev = get_device(vid);
 392
 393         if (dev == NULL)
 394                 return;
 395
 396         if (rte_vdpa_get_device(did) == NULL)
 397                 return;
 398
 399         dev->vdpa_dev_id = did;
 400 }
 401
 402 void
 403 vhost_detach_vdpa_device(int vid)
 404 {
 405         struct virtio_net *dev = get_device(vid);
 406
 407         if (dev == NULL)
 408                 return;
 409
 410         vhost_user_host_notifier_ctrl(vid, false);
 411
 412         dev->vdpa_dev_id = -1;
 413 }
 414
 415 void
 416 vhost_set_ifname(int vid, const char *if_name, unsigned int if_len)
 417 {
 418         struct virtio_net *dev;
 419         unsigned int len;
 420
 421         dev = get_device(vid);
 422         if (dev == NULL)
 423                 return;
 424
 425         len = if_len > sizeof(dev->ifname) ?
 426                 sizeof(dev->ifname) : if_len;
 427
 428         strncpy(dev->ifname, if_name, len);
 429         dev->ifname[sizeof(dev->ifname) - 1] = '\0';
 430 }
 431
 432 void
 433 vhost_enable_dequeue_zero_copy(int vid)
 434 {
 435         struct virtio_net *dev = get_device(vid);
 436
 437         if (dev == NULL)
 438                 return;
 439
 440         dev->dequeue_zero_copy = 1;
 441 }
 442
 443 void
 444 vhost_set_builtin_virtio_net(int vid, bool enable)
 445 {
 446         struct virtio_net *dev = get_device(vid);
 447
 448         if (dev == NULL)
 449                 return;
 450
 451         if (enable)
 452                 dev->flags |= VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 453         else
 454                 dev->flags &= ~VIRTIO_DEV_BUILTIN_VIRTIO_NET;
 455 }
 456
 457 int
 458 rte_vhost_get_mtu(int vid, uint16_t *mtu)
 459 {
 460         struct virtio_net *dev = get_device(vid);
 461
 462         if (!dev)
 463                 return -ENODEV;
 464
 465         if (!(dev->flags & VIRTIO_DEV_READY))
 466                 return -EAGAIN;
 467
 468         if (!(dev->features & (1ULL << VIRTIO_NET_F_MTU)))
 469                 return -ENOTSUP;
 470
 471         *mtu = dev->mtu;
 472
 473         return 0;
 474 }
 475
 476 int
 477 rte_vhost_get_numa_node(int vid)
 478 {
 479 #ifdef RTE_LIBRTE_VHOST_NUMA
 480         struct virtio_net *dev = get_device(vid);
 481         int numa_node;
 482         int ret;
 483
 484         if (dev == NULL || numa_available() != 0)
 485                 return -1;
 486
 487         ret = get_mempolicy(&numa_node, NULL, 0, dev,
 488                             MPOL_F_NODE | MPOL_F_ADDR);
 489         if (ret < 0) {
 490                 RTE_LOG(ERR, VHOST_CONFIG,
 491                         "(%d) failed to query numa node: %s\n",
 492                         vid, rte_strerror(errno));
 493                 return -1;
 494         }
 495
 496         return numa_node;
 497 #else
 498         RTE_SET_USED(vid);
 499         return -1;
 500 #endif
 501 }
 502
 503 uint32_t
 504 rte_vhost_get_queue_num(int vid)
 505 {
 506         struct virtio_net *dev = get_device(vid);
 507
 508         if (dev == NULL)
 509                 return 0;
 510
 511         return dev->nr_vring / 2;
 512 }
 513
 514 uint16_t
 515 rte_vhost_get_vring_num(int vid)
 516 {
 517         struct virtio_net *dev = get_device(vid);
 518
 519         if (dev == NULL)
 520                 return 0;
 521
 522         return dev->nr_vring;
 523 }
 524
 525 int
 526 rte_vhost_get_ifname(int vid, char *buf, size_t len)
 527 {
 528         struct virtio_net *dev = get_device(vid);
 529
 530         if (dev == NULL)
 531                 return -1;
 532
 533         len = RTE_MIN(len, sizeof(dev->ifname));
 534
 535         strncpy(buf, dev->ifname, len);
 536         buf[len - 1] = '\0';
 537
 538         return 0;
 539 }
 540
 541 int
 542 rte_vhost_get_negotiated_features(int vid, uint64_t *features)
 543 {
 544         struct virtio_net *dev;
 545
 546         dev = get_device(vid);
 547         if (!dev)
 548                 return -1;
 549
 550         *features = dev->features;
 551         return 0;
 552 }
 553
 554 int
 555 rte_vhost_get_mem_table(int vid, struct rte_vhost_memory **mem)
 556 {
 557         struct virtio_net *dev;
 558         struct rte_vhost_memory *m;
 559         size_t size;
 560
 561         dev = get_device(vid);
 562         if (!dev)
 563                 return -1;
 564
 565         size = dev->mem->nregions * sizeof(struct rte_vhost_mem_region);
 566         m = malloc(sizeof(struct rte_vhost_memory) + size);
 567         if (!m)
 568                 return -1;
 569
 570         m->nregions = dev->mem->nregions;
 571         memcpy(m->regions, dev->mem->regions, size);
 572         *mem = m;
 573
 574         return 0;
 575 }
 576
 577 int
 578 rte_vhost_get_vhost_vring(int vid, uint16_t vring_idx,
 579                           struct rte_vhost_vring *vring)
 580 {
 581         struct virtio_net *dev;
 582         struct vhost_virtqueue *vq;
 583
 584         dev = get_device(vid);
 585         if (!dev)
 586                 return -1;
 587
 588         if (vring_idx >= VHOST_MAX_VRING)
 589                 return -1;
 590
 591         vq = dev->virtqueue[vring_idx];
 592         if (!vq)
 593                 return -1;
 594
 595         vring->desc  = vq->desc;
 596         vring->avail = vq->avail;
 597         vring->used  = vq->used;
 598         vring->log_guest_addr  = vq->log_guest_addr;
 599
 600         vring->callfd  = vq->callfd;
 601         vring->kickfd  = vq->kickfd;
 602         vring->size    = vq->size;
 603
 604         return 0;
 605 }
 606
 607 int
 608 rte_vhost_vring_call(int vid, uint16_t vring_idx)
 609 {
 610         struct virtio_net *dev;
 611         struct vhost_virtqueue *vq;
 612
 613         dev = get_device(vid);
 614         if (!dev)
 615                 return -1;
 616
 617         if (vring_idx >= VHOST_MAX_VRING)
 618                 return -1;
 619
 620         vq = dev->virtqueue[vring_idx];
 621         if (!vq)
 622                 return -1;
 623
 624         if (vq_is_packed(dev))
 625                 vhost_vring_call_packed(dev, vq);
 626         else
 627                 vhost_vring_call_split(dev, vq);
 628
 629         return 0;
 630 }
 631
 632 uint16_t
 633 rte_vhost_avail_entries(int vid, uint16_t queue_id)
 634 {
 635         struct virtio_net *dev;
 636         struct vhost_virtqueue *vq;
 637
 638         dev = get_device(vid);
 639         if (!dev)
 640                 return 0;
 641
 642         vq = dev->virtqueue[queue_id];
 643         if (!vq->enabled)
 644                 return 0;
 645
 646         return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx;
 647 }
 648
 649 static inline void
 650 vhost_enable_notify_split(struct vhost_virtqueue *vq, int enable)
 651 {
 652         if (enable)
 653                 vq->used->flags &= ~VRING_USED_F_NO_NOTIFY;
 654         else
 655                 vq->used->flags |= VRING_USED_F_NO_NOTIFY;
 656 }
 657
 658 static inline void
 659 vhost_enable_notify_packed(struct virtio_net *dev,
 660                 struct vhost_virtqueue *vq, int enable)
 661 {
 662         uint16_t flags;
 663
 664         if (!enable)
 665                 vq->device_event->flags = VRING_EVENT_F_DISABLE;
 666
 667         flags = VRING_EVENT_F_ENABLE;
 668         if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) {
 669                 flags = VRING_EVENT_F_DESC;
 670                 vq->device_event->off_wrap = vq->last_avail_idx |
 671                         vq->avail_wrap_counter << 15;
 672         }
 673
 674         rte_smp_wmb();
 675
 676         vq->device_event->flags = flags;
 677 }
 678
 679 int
 680 rte_vhost_enable_guest_notification(int vid, uint16_t queue_id, int enable)
 681 {
 682         struct virtio_net *dev = get_device(vid);
 683         struct vhost_virtqueue *vq;
 684
 685         if (!dev)
 686                 return -1;
 687
 688         vq = dev->virtqueue[queue_id];
 689
 690         if (vq_is_packed(dev))
 691                 vhost_enable_notify_packed(dev, vq, enable);
 692         else
 693                 vhost_enable_notify_split(vq, enable);
 694
 695         return 0;
 696 }
 697
 698 void
 699 rte_vhost_log_write(int vid, uint64_t addr, uint64_t len)
 700 {
 701         struct virtio_net *dev = get_device(vid);
 702
 703         if (dev == NULL)
 704                 return;
 705
 706         vhost_log_write(dev, addr, len);
 707 }
 708
 709 void
 710 rte_vhost_log_used_vring(int vid, uint16_t vring_idx,
 711                          uint64_t offset, uint64_t len)
 712 {
 713         struct virtio_net *dev;
 714         struct vhost_virtqueue *vq;
 715
 716         dev = get_device(vid);
 717         if (dev == NULL)
 718                 return;
 719
 720         if (vring_idx >= VHOST_MAX_VRING)
 721                 return;
 722         vq = dev->virtqueue[vring_idx];
 723         if (!vq)
 724                 return;
 725
 726         vhost_log_used_vring(dev, vq, offset, len);
 727 }
 728
 729 uint32_t
 730 rte_vhost_rx_queue_count(int vid, uint16_t qid)
 731 {
 732         struct virtio_net *dev;
 733         struct vhost_virtqueue *vq;
 734
 735         dev = get_device(vid);
 736         if (dev == NULL)
 737                 return 0;
 738
 739         if (unlikely(qid >= dev->nr_vring || (qid & 1) == 0)) {
 740                 RTE_LOG(ERR, VHOST_DATA, "(%d) %s: invalid virtqueue idx %d.\n",
 741                         dev->vid, __func__, qid);
 742                 return 0;
 743         }
 744
 745         vq = dev->virtqueue[qid];
 746         if (vq == NULL)
 747                 return 0;
 748
 749         if (unlikely(vq->enabled == 0 || vq->avail == NULL))
 750                 return 0;
 751
 752         return *((volatile uint16_t *)&vq->avail->idx) - vq->last_avail_idx;
 753 }
 754
 755 int rte_vhost_get_vdpa_device_id(int vid)
 756 {
 757         struct virtio_net *dev = get_device(vid);
 758
 759         if (dev == NULL)
 760                 return -1;
 761
 762         return dev->vdpa_dev_id;
 763 }
 764
 765 int rte_vhost_get_log_base(int vid, uint64_t *log_base,
 766                 uint64_t *log_size)
 767 {
 768         struct virtio_net *dev = get_device(vid);
 769
 770         if (!dev)
 771                 return -1;
 772
 773         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 774                 RTE_LOG(ERR, VHOST_DATA,
 775                         "(%d) %s: built-in vhost net backend is disabled.\n",
 776                         dev->vid, __func__);
 777                 return -1;
 778         }
 779
 780         *log_base = dev->log_base;
 781         *log_size = dev->log_size;
 782
 783         return 0;
 784 }
 785
 786 int rte_vhost_get_vring_base(int vid, uint16_t queue_id,
 787                 uint16_t *last_avail_idx, uint16_t *last_used_idx)
 788 {
 789         struct virtio_net *dev = get_device(vid);
 790
 791         if (!dev)
 792                 return -1;
 793
 794         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 795                 RTE_LOG(ERR, VHOST_DATA,
 796                         "(%d) %s: built-in vhost net backend is disabled.\n",
 797                         dev->vid, __func__);
 798                 return -1;
 799         }
 800
 801         *last_avail_idx = dev->virtqueue[queue_id]->last_avail_idx;
 802         *last_used_idx = dev->virtqueue[queue_id]->last_used_idx;
 803
 804         return 0;
 805 }
 806
 807 int rte_vhost_set_vring_base(int vid, uint16_t queue_id,
 808                 uint16_t last_avail_idx, uint16_t last_used_idx)
 809 {
 810         struct virtio_net *dev = get_device(vid);
 811
 812         if (!dev)
 813                 return -1;
 814
 815         if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
 816                 RTE_LOG(ERR, VHOST_DATA,
 817                         "(%d) %s: built-in vhost net backend is disabled.\n",
 818                         dev->vid, __func__);
 819                 return -1;
 820         }
 821
 822         dev->virtqueue[queue_id]->last_avail_idx = last_avail_idx;
 823         dev->virtqueue[queue_id]->last_used_idx = last_used_idx;
 824
 825         return 0;
 826 }