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             addr += VHOST_LOG_CHUNK;
  41             continue;
  42         }
  43         /* Data must be read atomically. We don't really
  44          * need the barrier semantics of __sync
  45          * builtins, but it's easier to use them than
  46          * roll our own. */
  47         log = __sync_fetch_and_and(from, 0);
  48         while ((bit = sizeof(log) > sizeof(int) ?
  49                 ffsll(log) : ffs(log))) {
  50             ram_addr_t ram_addr;
  51             bit -= 1;
  52             ram_addr = cpu_get_physical_page_desc(addr + bit * VHOST_LOG_PAGE);
  53             cpu_physical_memory_set_dirty(ram_addr);
  54             log &= ~(0x1ull << bit);
  55         }
  56         addr += VHOST_LOG_CHUNK;
  57     }
  58 }
  59
  60 static int vhost_client_sync_dirty_bitmap(CPUPhysMemoryClient *client,
  61                                           target_phys_addr_t start_addr,
  62                                           target_phys_addr_t end_addr)
  63 {
  64     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
  65     int i;
  66     if (!dev->log_enabled || !dev->started) {
  67         return 0;
  68     }
  69     for (i = 0; i < dev->mem->nregions; ++i) {
  70         struct vhost_memory_region *reg = dev->mem->regions + i;
  71         vhost_dev_sync_region(dev, start_addr, end_addr,
  72                               reg->guest_phys_addr,
  73                               range_get_last(reg->guest_phys_addr,
  74                                              reg->memory_size));
  75     }
  76     for (i = 0; i < dev->nvqs; ++i) {
  77         struct vhost_virtqueue *vq = dev->vqs + i;
  78         vhost_dev_sync_region(dev, start_addr, end_addr, vq->used_phys,
  79                               range_get_last(vq->used_phys, vq->used_size));
  80     }
  81     return 0;
  82 }
  83
  84 /* Assign/unassign. Keep an unsorted array of non-overlapping
  85  * memory regions in dev->mem. */
  86 static void vhost_dev_unassign_memory(struct vhost_dev *dev,
  87                                       uint64_t start_addr,
  88                                       uint64_t size)
  89 {
  90     int from, to, n = dev->mem->nregions;
  91     /* Track overlapping/split regions for sanity checking. */
  92     int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0;
  93
  94     for (from = 0, to = 0; from < n; ++from, ++to) {
  95         struct vhost_memory_region *reg = dev->mem->regions + to;
  96         uint64_t reglast;
  97         uint64_t memlast;
  98         uint64_t change;
  99
 100         /* clone old region */
 101         if (to != from) {
 102             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 103         }
 104
 105         /* No overlap is simple */
 106         if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size,
 107                             start_addr, size)) {
 108             continue;
 109         }
 110
 111         /* Split only happens if supplied region
 112          * is in the middle of an existing one. Thus it can not
 113          * overlap with any other existing region. */
 114         assert(!split);
 115
 116         reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 117         memlast = range_get_last(start_addr, size);
 118
 119         /* Remove whole region */
 120         if (start_addr <= reg->guest_phys_addr && memlast >= reglast) {
 121             --dev->mem->nregions;
 122             --to;
 123             assert(to >= 0);
 124             ++overlap_middle;
 125             continue;
 126         }
 127
 128         /* Shrink region */
 129         if (memlast >= reglast) {
 130             reg->memory_size = start_addr - reg->guest_phys_addr;
 131             assert(reg->memory_size);
 132             assert(!overlap_end);
 133             ++overlap_end;
 134             continue;
 135         }
 136
 137         /* Shift region */
 138         if (start_addr <= reg->guest_phys_addr) {
 139             change = memlast + 1 - reg->guest_phys_addr;
 140             reg->memory_size -= change;
 141             reg->guest_phys_addr += change;
 142             reg->userspace_addr += change;
 143             assert(reg->memory_size);
 144             assert(!overlap_start);
 145             ++overlap_start;
 146             continue;
 147         }
 148
 149         /* This only happens if supplied region
 150          * is in the middle of an existing one. Thus it can not
 151          * overlap with any other existing region. */
 152         assert(!overlap_start);
 153         assert(!overlap_end);
 154         assert(!overlap_middle);
 155         /* Split region: shrink first part, shift second part. */
 156         memcpy(dev->mem->regions + n, reg, sizeof *reg);
 157         reg->memory_size = start_addr - reg->guest_phys_addr;
 158         assert(reg->memory_size);
 159         change = memlast + 1 - reg->guest_phys_addr;
 160         reg = dev->mem->regions + n;
 161         reg->memory_size -= change;
 162         assert(reg->memory_size);
 163         reg->guest_phys_addr += change;
 164         reg->userspace_addr += change;
 165         /* Never add more than 1 region */
 166         assert(dev->mem->nregions == n);
 167         ++dev->mem->nregions;
 168         ++split;
 169     }
 170 }
 171
 172 /* Called after unassign, so no regions overlap the given range. */
 173 static void vhost_dev_assign_memory(struct vhost_dev *dev,
 174                                     uint64_t start_addr,
 175                                     uint64_t size,
 176                                     uint64_t uaddr)
 177 {
 178     int from, to;
 179     struct vhost_memory_region *merged = NULL;
 180     for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) {
 181         struct vhost_memory_region *reg = dev->mem->regions + to;
 182         uint64_t prlast, urlast;
 183         uint64_t pmlast, umlast;
 184         uint64_t s, e, u;
 185
 186         /* clone old region */
 187         if (to != from) {
 188             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 189         }
 190         prlast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 191         pmlast = range_get_last(start_addr, size);
 192         urlast = range_get_last(reg->userspace_addr, reg->memory_size);
 193         umlast = range_get_last(uaddr, size);
 194
 195         /* check for overlapping regions: should never happen. */
 196         assert(prlast < start_addr || pmlast < reg->guest_phys_addr);
 197         /* Not an adjacent or overlapping region - do not merge. */
 198         if ((prlast + 1 != start_addr || urlast + 1 != uaddr) &&
 199             (pmlast + 1 != reg->guest_phys_addr ||
 200              umlast + 1 != reg->userspace_addr)) {
 201             continue;
 202         }
 203
 204         if (merged) {
 205             --to;
 206             assert(to >= 0);
 207         } else {
 208             merged = reg;
 209         }
 210         u = MIN(uaddr, reg->userspace_addr);
 211         s = MIN(start_addr, reg->guest_phys_addr);
 212         e = MAX(pmlast, prlast);
 213         uaddr = merged->userspace_addr = u;
 214         start_addr = merged->guest_phys_addr = s;
 215         size = merged->memory_size = e - s + 1;
 216         assert(merged->memory_size);
 217     }
 218
 219     if (!merged) {
 220         struct vhost_memory_region *reg = dev->mem->regions + to;
 221         memset(reg, 0, sizeof *reg);
 222         reg->memory_size = size;
 223         assert(reg->memory_size);
 224         reg->guest_phys_addr = start_addr;
 225         reg->userspace_addr = uaddr;
 226         ++to;
 227     }
 228     assert(to <= dev->mem->nregions + 1);
 229     dev->mem->nregions = to;
 230 }
 231
 232 static uint64_t vhost_get_log_size(struct vhost_dev *dev)
 233 {
 234     uint64_t log_size = 0;
 235     int i;
 236     for (i = 0; i < dev->mem->nregions; ++i) {
 237         struct vhost_memory_region *reg = dev->mem->regions + i;
 238         uint64_t last = range_get_last(reg->guest_phys_addr,
 239                                        reg->memory_size);
 240         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 241     }
 242     for (i = 0; i < dev->nvqs; ++i) {
 243         struct vhost_virtqueue *vq = dev->vqs + i;
 244         uint64_t last = vq->used_phys + vq->used_size - 1;
 245         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 246     }
 247     return log_size;
 248 }
 249
 250 static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
 251 {
 252     vhost_log_chunk_t *log;
 253     uint64_t log_base;
 254     int r;
 255     if (size) {
 256         log = qemu_mallocz(size * sizeof *log);
 257     } else {
 258         log = NULL;
 259     }
 260     log_base = (uint64_t)(unsigned long)log;
 261     r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
 262     assert(r >= 0);
 263     vhost_client_sync_dirty_bitmap(&dev->client, 0,
 264                                    (target_phys_addr_t)~0x0ull);
 265     if (dev->log) {
 266         qemu_free(dev->log);
 267     }
 268     dev->log = log;
 269     dev->log_size = size;
 270 }
 271
 272 static int vhost_verify_ring_mappings(struct vhost_dev *dev,
 273                                       uint64_t start_addr,
 274                                       uint64_t size)
 275 {
 276     int i;
 277     for (i = 0; i < dev->nvqs; ++i) {
 278         struct vhost_virtqueue *vq = dev->vqs + i;
 279         target_phys_addr_t l;
 280         void *p;
 281
 282         if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {
 283             continue;
 284         }
 285         l = vq->ring_size;
 286         p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
 287         if (!p || l != vq->ring_size) {
 288             fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
 289             return -ENOMEM;
 290         }
 291         if (p != vq->ring) {
 292             fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
 293             return -EBUSY;
 294         }
 295         cpu_physical_memory_unmap(p, l, 0, 0);
 296     }
 297     return 0;
 298 }
 299
 300 static void vhost_client_set_memory(CPUPhysMemoryClient *client,
 301                                     target_phys_addr_t start_addr,
 302                                     ram_addr_t size,
 303                                     ram_addr_t phys_offset,
 304                                     bool log_dirty)
 305 {
 306     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
 307     ram_addr_t flags = phys_offset & ~TARGET_PAGE_MASK;
 308     int s = offsetof(struct vhost_memory, regions) +
 309         (dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
 310     uint64_t log_size;
 311     int r;
 312     dev->mem = qemu_realloc(dev->mem, s);
 313
 314     if (log_dirty) {
 315         flags = IO_MEM_UNASSIGNED;
 316     }
 317
 318     assert(size);
 319
 320     vhost_dev_unassign_memory(dev, start_addr, size);
 321     if (flags == IO_MEM_RAM) {
 322         /* Add given mapping, merging adjacent regions if any */
 323         vhost_dev_assign_memory(dev, start_addr, size,
 324                                 (uintptr_t)qemu_get_ram_ptr(phys_offset));
 325     } else {
 326         /* Remove old mapping for this memory, if any. */
 327         vhost_dev_unassign_memory(dev, start_addr, size);
 328     }
 329
 330     if (!dev->started) {
 331         return;
 332     }
 333
 334     if (dev->started) {
 335         r = vhost_verify_ring_mappings(dev, start_addr, size);
 336         assert(r >= 0);
 337     }
 338
 339     if (!dev->log_enabled) {
 340         r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 341         assert(r >= 0);
 342         return;
 343     }
 344     log_size = vhost_get_log_size(dev);
 345     /* We allocate an extra 4K bytes to log,
 346      * to reduce the * number of reallocations. */
 347 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
 348     /* To log more, must increase log size before table update. */
 349     if (dev->log_size < log_size) {
 350         vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
 351     }
 352     r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 353     assert(r >= 0);
 354     /* To log less, can only decrease log size after table update. */
 355     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
 356         vhost_dev_log_resize(dev, log_size);
 357     }
 358 }
 359
 360 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
 361                                     struct vhost_virtqueue *vq,
 362                                     unsigned idx, bool enable_log)
 363 {
 364     struct vhost_vring_addr addr = {
 365         .index = idx,
 366         .desc_user_addr = (uint64_t)(unsigned long)vq->desc,
 367         .avail_user_addr = (uint64_t)(unsigned long)vq->avail,
 368         .used_user_addr = (uint64_t)(unsigned long)vq->used,
 369         .log_guest_addr = vq->used_phys,
 370         .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
 371     };
 372     int r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
 373     if (r < 0) {
 374         return -errno;
 375     }
 376     return 0;
 377 }
 378
 379 static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
 380 {
 381     uint64_t features = dev->acked_features;
 382     int r;
 383     if (enable_log) {
 384         features |= 0x1 << VHOST_F_LOG_ALL;
 385     }
 386     r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
 387     return r < 0 ? -errno : 0;
 388 }
 389
 390 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 391 {
 392     int r, t, i;
 393     r = vhost_dev_set_features(dev, enable_log);
 394     if (r < 0) {
 395         goto err_features;
 396     }
 397     for (i = 0; i < dev->nvqs; ++i) {
 398         r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 399                                      enable_log);
 400         if (r < 0) {
 401             goto err_vq;
 402         }
 403     }
 404     return 0;
 405 err_vq:
 406     for (; i >= 0; --i) {
 407         t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 408                                      dev->log_enabled);
 409         assert(t >= 0);
 410     }
 411     t = vhost_dev_set_features(dev, dev->log_enabled);
 412     assert(t >= 0);
 413 err_features:
 414     return r;
 415 }
 416
 417 static int vhost_client_migration_log(CPUPhysMemoryClient *client,
 418                                       int enable)
 419 {
 420     struct vhost_dev *dev = container_of(client, struct vhost_dev, client);
 421     int r;
 422     if (!!enable == dev->log_enabled) {
 423         return 0;
 424     }
 425     if (!dev->started) {
 426         dev->log_enabled = enable;
 427         return 0;
 428     }
 429     if (!enable) {
 430         r = vhost_dev_set_log(dev, false);
 431         if (r < 0) {
 432             return r;
 433         }
 434         if (dev->log) {
 435             qemu_free(dev->log);
 436         }
 437         dev->log = NULL;
 438         dev->log_size = 0;
 439     } else {
 440         vhost_dev_log_resize(dev, vhost_get_log_size(dev));
 441         r = vhost_dev_set_log(dev, true);
 442         if (r < 0) {
 443             return r;
 444         }
 445     }
 446     dev->log_enabled = enable;
 447     return 0;
 448 }
 449
 450 static int vhost_virtqueue_init(struct vhost_dev *dev,
 451                                 struct VirtIODevice *vdev,
 452                                 struct vhost_virtqueue *vq,
 453                                 unsigned idx)
 454 {
 455     target_phys_addr_t s, l, a;
 456     int r;
 457     struct vhost_vring_file file = {
 458         .index = idx,
 459     };
 460     struct vhost_vring_state state = {
 461         .index = idx,
 462     };
 463     struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
 464
 465     if (!vdev->binding->set_host_notifier) {
 466         fprintf(stderr, "binding does not support host notifiers\n");
 467         return -ENOSYS;
 468     }
 469
 470     vq->num = state.num = virtio_queue_get_num(vdev, idx);
 471     r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
 472     if (r) {
 473         return -errno;
 474     }
 475
 476     state.num = virtio_queue_get_last_avail_idx(vdev, idx);
 477     r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
 478     if (r) {
 479         return -errno;
 480     }
 481
 482     s = l = virtio_queue_get_desc_size(vdev, idx);
 483     a = virtio_queue_get_desc_addr(vdev, idx);
 484     vq->desc = cpu_physical_memory_map(a, &l, 0);
 485     if (!vq->desc || l != s) {
 486         r = -ENOMEM;
 487         goto fail_alloc_desc;
 488     }
 489     s = l = virtio_queue_get_avail_size(vdev, idx);
 490     a = virtio_queue_get_avail_addr(vdev, idx);
 491     vq->avail = cpu_physical_memory_map(a, &l, 0);
 492     if (!vq->avail || l != s) {
 493         r = -ENOMEM;
 494         goto fail_alloc_avail;
 495     }
 496     vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
 497     vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
 498     vq->used = cpu_physical_memory_map(a, &l, 1);
 499     if (!vq->used || l != s) {
 500         r = -ENOMEM;
 501         goto fail_alloc_used;
 502     }
 503
 504     vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
 505     vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
 506     vq->ring = cpu_physical_memory_map(a, &l, 1);
 507     if (!vq->ring || l != s) {
 508         r = -ENOMEM;
 509         goto fail_alloc_ring;
 510     }
 511
 512     r = vhost_virtqueue_set_addr(dev, vq, idx, dev->log_enabled);
 513     if (r < 0) {
 514         r = -errno;
 515         goto fail_alloc;
 516     }
 517     r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, true);
 518     if (r < 0) {
 519         fprintf(stderr, "Error binding host notifier: %d\n", -r);
 520         goto fail_host_notifier;
 521     }
 522
 523     file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
 524     r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
 525     if (r) {
 526         r = -errno;
 527         goto fail_kick;
 528     }
 529
 530     file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
 531     r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
 532     if (r) {
 533         r = -errno;
 534         goto fail_call;
 535     }
 536
 537     return 0;
 538
 539 fail_call:
 540 fail_kick:
 541     vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
 542 fail_host_notifier:
 543 fail_alloc:
 544     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 545                               0, 0);
 546 fail_alloc_ring:
 547     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 548                               0, 0);
 549 fail_alloc_used:
 550     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 551                               0, 0);
 552 fail_alloc_avail:
 553     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 554                               0, 0);
 555 fail_alloc_desc:
 556     return r;
 557 }
 558
 559 static void vhost_virtqueue_cleanup(struct vhost_dev *dev,
 560                                     struct VirtIODevice *vdev,
 561                                     struct vhost_virtqueue *vq,
 562                                     unsigned idx)
 563 {
 564     struct vhost_vring_state state = {
 565         .index = idx,
 566     };
 567     int r;
 568     r = vdev->binding->set_host_notifier(vdev->binding_opaque, idx, false);
 569     if (r < 0) {
 570         fprintf(stderr, "vhost VQ %d host cleanup failed: %d\n", idx, r);
 571         fflush(stderr);
 572     }
 573     assert (r >= 0);
 574     r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);
 575     if (r < 0) {
 576         fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
 577         fflush(stderr);
 578     }
 579     virtio_queue_set_last_avail_idx(vdev, idx, state.num);
 580     assert (r >= 0);
 581     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 582                               0, virtio_queue_get_ring_size(vdev, idx));
 583     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 584                               1, virtio_queue_get_used_size(vdev, idx));
 585     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 586                               0, virtio_queue_get_avail_size(vdev, idx));
 587     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 588                               0, virtio_queue_get_desc_size(vdev, idx));
 589 }
 590
 591 int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
 592 {
 593     uint64_t features;
 594     int r;
 595     if (devfd >= 0) {
 596         hdev->control = devfd;
 597     } else {
 598         hdev->control = open("/dev/vhost-net", O_RDWR);
 599         if (hdev->control < 0) {
 600             return -errno;
 601         }
 602     }
 603     r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
 604     if (r < 0) {
 605         goto fail;
 606     }
 607
 608     r = ioctl(hdev->control, VHOST_GET_FEATURES, &features);
 609     if (r < 0) {
 610         goto fail;
 611     }
 612     hdev->features = features;
 613
 614     hdev->client.set_memory = vhost_client_set_memory;
 615     hdev->client.sync_dirty_bitmap = vhost_client_sync_dirty_bitmap;
 616     hdev->client.migration_log = vhost_client_migration_log;
 617     hdev->client.log_start = NULL;
 618     hdev->client.log_stop = NULL;
 619     hdev->mem = qemu_mallocz(offsetof(struct vhost_memory, regions));
 620     hdev->log = NULL;
 621     hdev->log_size = 0;
 622     hdev->log_enabled = false;
 623     hdev->started = false;
 624     cpu_register_phys_memory_client(&hdev->client);
 625     hdev->force = force;
 626     return 0;
 627 fail:
 628     r = -errno;
 629     close(hdev->control);
 630     return r;
 631 }
 632
 633 void vhost_dev_cleanup(struct vhost_dev *hdev)
 634 {
 635     cpu_unregister_phys_memory_client(&hdev->client);
 636     qemu_free(hdev->mem);
 637     close(hdev->control);
 638 }
 639
 640 bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev)
 641 {
 642     return !vdev->binding->query_guest_notifiers ||
 643         vdev->binding->query_guest_notifiers(vdev->binding_opaque) ||
 644         hdev->force;
 645 }
 646
 647 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 648 {
 649     int i, r;
 650     if (!vdev->binding->set_guest_notifiers) {
 651         fprintf(stderr, "binding does not support guest notifiers\n");
 652         r = -ENOSYS;
 653         goto fail;
 654     }
 655
 656     r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, true);
 657     if (r < 0) {
 658         fprintf(stderr, "Error binding guest notifier: %d\n", -r);
 659         goto fail_notifiers;
 660     }
 661
 662     r = vhost_dev_set_features(hdev, hdev->log_enabled);
 663     if (r < 0) {
 664         goto fail_features;
 665     }
 666     r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
 667     if (r < 0) {
 668         r = -errno;
 669         goto fail_mem;
 670     }
 671     for (i = 0; i < hdev->nvqs; ++i) {
 672         r = vhost_virtqueue_init(hdev,
 673                                  vdev,
 674                                  hdev->vqs + i,
 675                                  i);
 676         if (r < 0) {
 677             goto fail_vq;
 678         }
 679     }
 680
 681     if (hdev->log_enabled) {
 682         hdev->log_size = vhost_get_log_size(hdev);
 683         hdev->log = hdev->log_size ?
 684             qemu_mallocz(hdev->log_size * sizeof *hdev->log) : NULL;
 685         r = ioctl(hdev->control, VHOST_SET_LOG_BASE,
 686                   (uint64_t)(unsigned long)hdev->log);
 687         if (r < 0) {
 688             r = -errno;
 689             goto fail_log;
 690         }
 691     }
 692
 693     hdev->started = true;
 694
 695     return 0;
 696 fail_log:
 697 fail_vq:
 698     while (--i >= 0) {
 699         vhost_virtqueue_cleanup(hdev,
 700                                 vdev,
 701                                 hdev->vqs + i,
 702                                 i);
 703     }
 704 fail_mem:
 705 fail_features:
 706     vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
 707 fail_notifiers:
 708 fail:
 709     return r;
 710 }
 711
 712 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
 713 {
 714     int i, r;
 715
 716     for (i = 0; i < hdev->nvqs; ++i) {
 717         vhost_virtqueue_cleanup(hdev,
 718                                 vdev,
 719                                 hdev->vqs + i,
 720                                 i);
 721     }
 722     vhost_client_sync_dirty_bitmap(&hdev->client, 0,
 723                                    (target_phys_addr_t)~0x0ull);
 724     r = vdev->binding->set_guest_notifiers(vdev->binding_opaque, false);
 725     if (r < 0) {
 726         fprintf(stderr, "vhost guest notifier cleanup failed: %d\n", r);
 727         fflush(stderr);
 728     }
 729     assert (r >= 0);
 730
 731     hdev->started = false;
 732     qemu_free(hdev->log);
 733     hdev->log_size = 0;
 734 }