hw/vhost.c

   1 /*
   2  * vhost support
   3  *
   4  * Copyright Red Hat, Inc. 2010
   5  *
   6  * Authors:
   7  *  Michael S. Tsirkin <mst@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include <sys/ioctl.h>
  14 #include "vhost.h"
  15 #include "hw/hw.h"
  16 #include "range.h"
  17 #include <linux/vhost.h>
  18
  19 static void vhost_dev_sync_region(struct vhost_dev *dev,
  20                                   uint64_t mfirst, uint64_t mlast,
  21                                   uint64_t rfirst, uint64_t rlast)
  22 {
  23     uint64_t start = MAX(mfirst, rfirst);
  24     uint64_t end = MIN(mlast, rlast);
  25     vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
  26     vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
  27     uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
  28
  29     assert(end / VHOST_LOG_CHUNK < dev->log_size);
  30     assert(start / VHOST_LOG_CHUNK < dev->log_size);
  31     if (end < start) {
  32         return;
  33     }
  34     for (;from < to; ++from) {
  35         vhost_log_chunk_t log;
  36         int bit;
  37         /* We first check with non-atomic: much cheaper,
  38          * and we expect non-dirty to be the common case. */
  39         if (!*from) {
  40             continue;
  41         }
  42         /* Data must be read atomically. We don't really
  43          * need the barrier semantics of __sync
  44          * builtins, but it's easier to use them than
  45          * roll our own. */
  46         log = __sync_fetch_and_and(from, 0);
  47         while ((bit = sizeof(log) > sizeof(int) ?
  48                 ffsll(log) : ffs(log))) {
  49             bit -= 1;
  50             cpu_physical_memory_set_dirty(addr + bit * VHOST_LOG_PAGE);
  51             log &= ~(0x1ull << bit);
  52         }
  53         addr += VHOST_LOG_CHUNK;
  54     }
  55 }
  56
  57 static int vhost_client_sync_dirty_bitmap(CPUPhysMemoryClient *client,
  58                                           target_phys_addr_t start_addr,
  59                                           target_phys_addr_t end_addr)
  60 {
  61     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
  62     int i;
  63     if (!dev->log_enabled || !dev->started) {
  64         return 0;
  65     }
  66     for (i = 0; i < dev->mem->nregions; ++i) {
  67         struct vhost_memory_region *reg = dev->mem->regions + i;
  68         vhost_dev_sync_region(dev, start_addr, end_addr,
  69                               reg->guest_phys_addr,
  70                               range_get_last(reg->guest_phys_addr,
  71                                              reg->memory_size));
  72     }
  73     for (i = 0; i < dev->nvqs; ++i) {
  74         struct vhost_virtqueue *vq = dev->vqs + i;
  75         vhost_dev_sync_region(dev, start_addr, end_addr, vq->used_phys,
  76                               range_get_last(vq->used_phys, vq->used_size));
  77     }
  78     return 0;
  79 }
  80
  81 /* Assign/unassign. Keep an unsorted array of non-overlapping
  82  * memory regions in dev->mem. */
  83 static void vhost_dev_unassign_memory(struct vhost_dev *dev,
  84                                       uint64_t start_addr,
  85                                       uint64_t size)
  86 {
  87     int from, to, n = dev->mem->nregions;
  88     /* Track overlapping/split regions for sanity checking. */
  89     int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0;
  90
  91     for (from = 0, to = 0; from < n; ++from, ++to) {
  92         struct vhost_memory_region *reg = dev->mem->regions + to;
  93         uint64_t reglast;
  94         uint64_t memlast;
  95         uint64_t change;
  96
  97         /* clone old region */
  98         if (to != from) {
  99             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 100         }
 101
 102         /* No overlap is simple */
 103         if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size,
 104                             start_addr, size)) {
 105             continue;
 106         }
 107
 108         /* Split only happens if supplied region
 109          * is in the middle of an existing one. Thus it can not
 110          * overlap with any other existing region. */
 111         assert(!split);
 112
 113         reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 114         memlast = range_get_last(start_addr, size);
 115
 116         /* Remove whole region */
 117         if (start_addr <= reg->guest_phys_addr && memlast >= reglast) {
 118             --dev->mem->nregions;
 119             --to;
 120             assert(to >= 0);
 121             ++overlap_middle;
 122             continue;
 123         }
 124
 125         /* Shrink region */
 126         if (memlast >= reglast) {
 127             reg->memory_size = start_addr - reg->guest_phys_addr;
 128             assert(reg->memory_size);
 129             assert(!overlap_end);
 130             ++overlap_end;
 131             continue;
 132         }
 133
 134         /* Shift region */
 135         if (start_addr <= reg->guest_phys_addr) {
 136             change = memlast + 1 - reg->guest_phys_addr;
 137             reg->memory_size -= change;
 138             reg->guest_phys_addr += change;
 139             reg->userspace_addr += change;
 140             assert(reg->memory_size);
 141             assert(!overlap_start);
 142             ++overlap_start;
 143             continue;
 144         }
 145
 146         /* This only happens if supplied region
 147          * is in the middle of an existing one. Thus it can not
 148          * overlap with any other existing region. */
 149         assert(!overlap_start);
 150         assert(!overlap_end);
 151         assert(!overlap_middle);
 152         /* Split region: shrink first part, shift second part. */
 153         memcpy(dev->mem->regions + n, reg, sizeof *reg);
 154         reg->memory_size = start_addr - reg->guest_phys_addr;
 155         assert(reg->memory_size);
 156         change = memlast + 1 - reg->guest_phys_addr;
 157         reg = dev->mem->regions + n;
 158         reg->memory_size -= change;
 159         assert(reg->memory_size);
 160         reg->guest_phys_addr += change;
 161         reg->userspace_addr += change;
 162         /* Never add more than 1 region */
 163         assert(dev->mem->nregions == n);
 164         ++dev->mem->nregions;
 165         ++split;
 166     }
 167 }
 168
 169 /* Called after unassign, so no regions overlap the given range. */
 170 static void vhost_dev_assign_memory(struct vhost_dev *dev,
 171                                     uint64_t start_addr,
 172                                     uint64_t size,
 173                                     uint64_t uaddr)
 174 {
 175     int from, to;
 176     struct vhost_memory_region *merged = NULL;
 177     for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) {
 178         struct vhost_memory_region *reg = dev->mem->regions + to;
 179         uint64_t prlast, urlast;
 180         uint64_t pmlast, umlast;
 181         uint64_t s, e, u;
 182
 183         /* clone old region */
 184         if (to != from) {
 185             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 186         }
 187         prlast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 188         pmlast = range_get_last(start_addr, size);
 189         urlast = range_get_last(reg->userspace_addr, reg->memory_size);
 190         umlast = range_get_last(uaddr, size);
 191
 192         /* check for overlapping regions: should never happen. */
 193         assert(prlast < start_addr || pmlast < reg->guest_phys_addr);
 194         /* Not an adjacent or overlapping region - do not merge. */
 195         if ((prlast + 1 != start_addr || urlast + 1 != uaddr) &&
 196             (pmlast + 1 != reg->guest_phys_addr ||
 197              umlast + 1 != reg->userspace_addr)) {
 198             continue;
 199         }
 200
 201         if (merged) {
 202             --to;
 203             assert(to >= 0);
 204         } else {
 205             merged = reg;
 206         }
 207         u = MIN(uaddr, reg->userspace_addr);
 208         s = MIN(start_addr, reg->guest_phys_addr);
 209         e = MAX(pmlast, prlast);
 210         uaddr = merged->userspace_addr = u;
 211         start_addr = merged->guest_phys_addr = s;
 212         size = merged->memory_size = e - s + 1;
 213         assert(merged->memory_size);
 214     }
 215
 216     if (!merged) {
 217         struct vhost_memory_region *reg = dev->mem->regions + to;
 218         memset(reg, 0, sizeof *reg);
 219         reg->memory_size = size;
 220         assert(reg->memory_size);
 221         reg->guest_phys_addr = start_addr;
 222         reg->userspace_addr = uaddr;
 223         ++to;
 224     }
 225     assert(to <= dev->mem->nregions + 1);
 226     dev->mem->nregions = to;
 227 }
 228
 229 static uint64_t vhost_get_log_size(struct vhost_dev *dev)
 230 {
 231     uint64_t log_size = 0;
 232     int i;
 233     for (i = 0; i < dev->mem->nregions; ++i) {
 234         struct vhost_memory_region *reg = dev->mem->regions + i;
 235         uint64_t last = range_get_last(reg->guest_phys_addr,
 236                                        reg->memory_size);
 237         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 238     }
 239     for (i = 0; i < dev->nvqs; ++i) {
 240         struct vhost_virtqueue *vq = dev->vqs + i;
 241         uint64_t last = vq->used_phys + vq->used_size - 1;
 242         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 243     }
 244     return log_size;
 245 }
 246
 247 static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
 248 {
 249     vhost_log_chunk_t *log;
 250     uint64_t log_base;
 251     int r;
 252     if (size) {
 253         log = qemu_mallocz(size * sizeof *log);
 254     } else {
 255         log = NULL;
 256     }
 257     log_base = (uint64_t)(unsigned long)log;
 258     r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
 259     assert(r >= 0);
 260     vhost_client_sync_dirty_bitmap(&dev->client, 0,
 261                                    (target_phys_addr_t)~0x0ull);
 262     if (dev->log) {
 263         qemu_free(dev->log);
 264     }
 265     dev->log = log;
 266     dev->log_size = size;
 267 }
 268
 269 static int vhost_verify_ring_mappings(struct vhost_dev *dev,
 270                                       uint64_t start_addr,
 271                                       uint64_t size)
 272 {
 273     int i;
 274     for (i = 0; i < dev->nvqs; ++i) {
 275         struct vhost_virtqueue *vq = dev->vqs + i;
 276         target_phys_addr_t l;
 277         void *p;
 278
 279         if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {
 280             continue;
 281         }
 282         l = vq->ring_size;
 283         p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
 284         if (!p || l != vq->ring_size) {
 285             fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
 286             return -ENOMEM;
 287         }
 288         if (p != vq->ring) {
 289             fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
 290             return -EBUSY;
 291         }
 292         cpu_physical_memory_unmap(p, l, 0, 0);
 293     }
 294     return 0;
 295 }
 296
 297 static void vhost_client_set_memory(CPUPhysMemoryClient *client,
 298                                     target_phys_addr_t start_addr,
 299                                     ram_addr_t size,
 300                                     ram_addr_t phys_offset)
 301 {
 302     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
 303     ram_addr_t flags = phys_offset & ~TARGET_PAGE_MASK;
 304     int s = offsetof(struct vhost_memory, regions) +
 305         (dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
 306     uint64_t log_size;
 307     int r;
 308     dev->mem = qemu_realloc(dev->mem, s);
 309
 310     assert(size);
 311
 312     vhost_dev_unassign_memory(dev, start_addr, size);
 313     if (flags == IO_MEM_RAM) {
 314         /* Add given mapping, merging adjacent regions if any */
 315         vhost_dev_assign_memory(dev, start_addr, size,
 316                                 (uintptr_t)qemu_get_ram_ptr(phys_offset));
 317     } else {
 318         /* Remove old mapping for this memory, if any. */
 319         vhost_dev_unassign_memory(dev, start_addr, size);
 320     }
 321
 322     if (!dev->started) {
 323         return;
 324     }
 325
 326     if (dev->started) {
 327         r = vhost_verify_ring_mappings(dev, start_addr, size);
 328         assert(r >= 0);
 329     }
 330
 331     if (!dev->log_enabled) {
 332         r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 333         assert(r >= 0);
 334         return;
 335     }
 336     log_size = vhost_get_log_size(dev);
 337     /* We allocate an extra 4K bytes to log,
 338      * to reduce the * number of reallocations. */
 339 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
 340     /* To log more, must increase log size before table update. */
 341     if (dev->log_size < log_size) {
 342         vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
 343     }
 344     r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 345     assert(r >= 0);
 346     /* To log less, can only decrease log size after table update. */
 347     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
 348         vhost_dev_log_resize(dev, log_size);
 349     }
 350 }
 351
 352 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
 353                                     struct vhost_virtqueue *vq,
 354                                     unsigned idx, bool enable_log)
 355 {
 356     struct vhost_vring_addr addr = {
 357         .index = idx,
 358         .desc_user_addr = (uint64_t)(unsigned long)vq->desc,
 359         .avail_user_addr = (uint64_t)(unsigned long)vq->avail,
 360         .used_user_addr = (uint64_t)(unsigned long)vq->used,
 361         .log_guest_addr = vq->used_phys,
 362         .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
 363     };
 364     int r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
 365     if (r < 0) {
 366         return -errno;
 367     }
 368     return 0;
 369 }
 370
 371 static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
 372 {
 373     uint64_t features = dev->acked_features;
 374     int r;
 375     if (enable_log) {
 376         features |= 0x1 << VHOST_F_LOG_ALL;
 377     }
 378     r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
 379     return r < 0 ? -errno : 0;
 380 }
 381
 382 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 383 {
 384     int r, t, i;
 385     r = vhost_dev_set_features(dev, enable_log);
 386     if (r < 0) {
 387         goto err_features;
 388     }
 389     for (i = 0; i < dev->nvqs; ++i) {
 390         r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 391                                      enable_log);
 392         if (r < 0) {
 393             goto err_vq;
 394         }
 395     }
 396     return 0;
 397 err_vq:
 398     for (; i >= 0; --i) {
 399         t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 400                                      dev->log_enabled);
 401         assert(t >= 0);
 402     }
 403     t = vhost_dev_set_features(dev, dev->log_enabled);
 404     assert(t >= 0);
 405 err_features:
 406     return r;
 407 }
 408
 409 static int vhost_client_migration_log(CPUPhysMemoryClient *client,
 410                                       int enable)
 411 {
 412     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
 413     int r;
 414     if (!!enable == dev->log_enabled) {
 415         return 0;
 416     }
 417     if (!dev->started) {
 418         dev->log_enabled = enable;
 419         return 0;
 420     }
 421     if (!enable) {
 422         r = vhost_dev_set_log(dev, false);
 423         if (r < 0) {
 424             return r;
 425         }
 426         if (dev->log) {
 427             qemu_free(dev->log);
 428         }
 429         dev->log = NULL;
 430         dev->log_size = 0;
 431     } else {
 432         vhost_dev_log_resize(dev, vhost_get_log_size(dev));
 433         r = vhost_dev_set_log(dev, true);
 434         if (r < 0) {
 435             return r;
 436         }
 437     }
 438     dev->log_enabled = enable;
 439     return 0;
 440 }
 441
 442 static int vhost_virtqueue_init(struct vhost_dev *dev,
 443                                 struct VirtIODevice *vdev,
 444                                 struct vhost_virtqueue *vq,
 445                                 unsigned idx)
 446 {
 447     target_phys_addr_t s, l, a;
 448     int r;
 449     struct vhost_vring_file file = {
 450         .index = idx,
 451     };
 452     struct vhost_vring_state state = {
 453         .index = idx,
 454     };
 455     struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
 456
 457     if (!vdev->binding->set_host_notifier) {
 458         fprintf(stderr, "binding does not support host notifiers\n");
 459         return -ENOSYS;
 460     }
 461
 462     vq->num = state.num = virtio_queue_get_num(vdev, idx);
 463     r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
 464     if (r) {
 465         return -errno;
 466     }
 467
 468     state.num = virtio_queue_get_last_avail_idx(vdev, idx);
 469     r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
 470     if (r) {
 471         return -errno;
 472     }
 473
 474     s = l = virtio_queue_get_desc_size(vdev, idx);
 475     a = virtio_queue_get_desc_addr(vdev, idx);
 476     vq->desc = cpu_physical_memory_map(a, &l, 0);
 477     if (!vq->desc || l != s) {
 478         r = -ENOMEM;
 479         goto fail_alloc_desc;
 480     }
 481     s = l = virtio_queue_get_avail_size(vdev, idx);
 482     a = virtio_queue_get_avail_addr(vdev, idx);
 483     vq->avail = cpu_physical_memory_map(a, &l, 0);
 484     if (!vq->avail || l != s) {
 485         r = -ENOMEM;
 486         goto fail_alloc_avail;
 487     }
 488     vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
 489     vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
 490     vq->used = cpu_physical_memory_map(a, &l, 1);
 491     if (!vq->used || l != s) {
 492         r = -ENOMEM;
 493         goto fail_alloc_used;
 494     }
 495
 496     vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
 497     vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
 498     vq->ring = cpu_physical_memory_map(a, &l, 1);
 499     if (!vq->ring || l != s) {
 500         r = -ENOMEM;
 501         goto fail_alloc_ring;
 502     }
 503
 504     r = vhost_virtqueue_set_addr(dev, vq, idx, dev->log_enabled);
 505     if (r < 0) {
 506         r = -errno;
 507         goto fail_alloc;
 508     }
 509     r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, true);
 510     if (r < 0) {
 511         fprintf(stderr, "Error binding host notifier: %d\n", -r);
 512         goto fail_host_notifier;
 513     }
 514
 515     file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
 516     r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
 517     if (r) {
 518         r = -errno;
 519         goto fail_kick;
 520     }
 521
 522     file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
 523     r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
 524     if (r) {
 525         r = -errno;
 526         goto fail_call;
 527     }
 528
 529     return 0;
 530
 531 fail_call:
 532 fail_kick:
 533     vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
 534 fail_host_notifier:
 535 fail_alloc:
 536     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 537                               0, 0);
 538 fail_alloc_ring:
 539     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 540                               0, 0);
 541 fail_alloc_used:
 542     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 543                               0, 0);
 544 fail_alloc_avail:
 545     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 546                               0, 0);
 547 fail_alloc_desc:
 548     return r;
 549 }
 550
 551 static void vhost_virtqueue_cleanup(struct vhost_dev *dev,
 552                                     struct VirtIODevice *vdev,
 553                                     struct vhost_virtqueue *vq,
 554                                     unsigned idx)
 555 {
 556     struct vhost_vring_state state = {
 557         .index = idx,
 558     };
 559     int r;
 560     r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
 561     if (r < 0) {
 562         fprintf(stderr, "vhost VQ %d host cleanup failed: %d\n", idx, r);
 563         fflush(stderr);
 564     }
 565     assert (r >= 0);
 566     r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);
 567     if (r < 0) {
 568         fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
 569         fflush(stderr);
 570     }
 571     virtio_queue_set_last_avail_idx(vdev, idx, state.num);
 572     assert (r >= 0);
 573     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 574                               0, virtio_queue_get_ring_size(vdev, idx));
 575     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 576                               1, virtio_queue_get_used_size(vdev, idx));
 577     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 578                               0, virtio_queue_get_avail_size(vdev, idx));
 579     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 580                               0, virtio_queue_get_desc_size(vdev, idx));
 581 }
 582
 583 int vhost_dev_init(struct vhost_dev *hdev, int devfd)
 584 {
 585     uint64_t features;
 586     int r;
 587     if (devfd >= 0) {
 588         hdev->control = devfd;
 589     } else {
 590         hdev->control = open("/dev/vhost-net", O_RDWR);
 591         if (hdev->control < 0) {
 592             return -errno;
 593         }
 594     }
 595     r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
 596     if (r < 0) {
 597         goto fail;
 598     }
 599
 600     r = ioctl(hdev->control, VHOST_GET_FEATURES, &features);
 601     if (r < 0) {
 602         goto fail;
 603     }
 604     hdev->features = features;
 605
 606     hdev->client.set_memory = vhost_client_set_memory;
 607     hdev->client.sync_dirty_bitmap = vhost_client_sync_dirty_bitmap;
 608     hdev->client.migration_log = vhost_client_migration_log;
 609     hdev->mem = qemu_mallocz(offsetof(struct vhost_memory, regions));
 610     hdev->log = NULL;
 611     hdev->log_size = 0;
 612     hdev->log_enabled = false;
 613     hdev->started = false;
 614     cpu_register_phys_memory_client(&hdev->client);
 615     return 0;
 616 fail:
 617     r = -errno;
 618     close(hdev->control);
 619     return r;
 620 }
 621
 622 void vhost_dev_cleanup(struct vhost_dev *hdev)
 623 {
 624     cpu_unregister_phys_memory_client(&hdev->client);
 625     qemu_free(hdev->mem);
 626     close(hdev->control);
 627 }
 628
 629 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 630 {
 631     int i, r;
 632     if (!vdev->binding->set_guest_notifiers) {
 633         fprintf(stderr, "binding does not support guest notifiers\n");
 634         r = -ENOSYS;
 635         goto fail;
 636     }
 637
 638     r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, true);
 639     if (r < 0) {
 640         fprintf(stderr, "Error binding guest notifier: %d\n", -r);
 641         goto fail_notifiers;
 642     }
 643
 644     r = vhost_dev_set_features(hdev, hdev->log_enabled);
 645     if (r < 0) {
 646         goto fail_features;
 647     }
 648     r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
 649     if (r < 0) {
 650         r = -errno;
 651         goto fail_mem;
 652     }
 653     for (i = 0; i < hdev->nvqs; ++i) {
 654         r = vhost_virtqueue_init(hdev,
 655                                  vdev,
 656                                  hdev->vqs + i,
 657                                  i);
 658         if (r < 0) {
 659             goto fail_vq;
 660         }
 661     }
 662
 663     if (hdev->log_enabled) {
 664         hdev->log_size = vhost_get_log_size(hdev);
 665         hdev->log = hdev->log_size ?
 666             qemu_mallocz(hdev->log_size * sizeof *hdev->log) : NULL;
 667         r = ioctl(hdev->control, VHOST_SET_LOG_BASE,
 668                   (uint64_t)(unsigned long)hdev->log);
 669         if (r < 0) {
 670             r = -errno;
 671             goto fail_log;
 672         }
 673     }
 674
 675     hdev->started = true;
 676
 677     return 0;
 678 fail_log:
 679 fail_vq:
 680     while (--i >= 0) {
 681         vhost_virtqueue_cleanup(hdev,
 682                                 vdev,
 683                                 hdev->vqs + i,
 684                                 i);
 685     }
 686 fail_mem:
 687 fail_features:
 688     vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
 689 fail_notifiers:
 690 fail:
 691     return r;
 692 }
 693
 694 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
 695 {
 696     int i, r;
 697
 698     for (i = 0; i < hdev->nvqs; ++i) {
 699         vhost_virtqueue_cleanup(hdev,
 700                                 vdev,
 701                                 hdev->vqs + i,
 702                                 i);
 703     }
 704     vhost_client_sync_dirty_bitmap(&hdev->client, 0,
 705                                    (target_phys_addr_t)~0x0ull);
 706     r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
 707     if (r < 0) {
 708         fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
 709         fflush(stderr);
 710     }
 711     assert (r >= 0);
 712
 713     hdev->started = false;
 714     qemu_free(hdev->log);
 715     hdev->log_size = 0;
 716 }