hw/virtio/vhost.c

   1 /*
   2  * vhost support
   3  *
   4  * Copyright Red Hat, Inc. 2010
   5  *
   6  * Authors:
   7  *  Michael S. Tsirkin <[email protected]>
   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  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu/osdep.h"
  17 #include "qapi/error.h"
  18 #include "hw/virtio/vhost.h"
  19 #include "qemu/atomic.h"
  20 #include "qemu/range.h"
  21 #include "qemu/error-report.h"
  22 #include "qemu/memfd.h"
  23 #include "standard-headers/linux/vhost_types.h"
  24 #include "hw/virtio/virtio-bus.h"
  25 #include "hw/virtio/virtio-access.h"
  26 #include "migration/blocker.h"
  27 #include "migration/qemu-file-types.h"
  28 #include "sysemu/dma.h"
  29 #include "trace.h"
  30
  31 /* enabled until disconnected backend stabilizes */
  32 #define _VHOST_DEBUG 1
  33
  34 #ifdef _VHOST_DEBUG
  35 #define VHOST_OPS_DEBUG(retval, fmt, ...) \
  36     do { \
  37         error_report(fmt ": %s (%d)", ## __VA_ARGS__, \
  38                      strerror(-retval), -retval); \
  39     } while (0)
  40 #else
  41 #define VHOST_OPS_DEBUG(retval, fmt, ...) \
  42     do { } while (0)
  43 #endif
  44
  45 static struct vhost_log *vhost_log;
  46 static struct vhost_log *vhost_log_shm;
  47
  48 static unsigned int used_memslots;
  49 static QLIST_HEAD(, vhost_dev) vhost_devices =
  50     QLIST_HEAD_INITIALIZER(vhost_devices);
  51
  52 bool vhost_has_free_slot(void)
  53 {
  54     unsigned int slots_limit = ~0U;
  55     struct vhost_dev *hdev;
  56
  57     QLIST_FOREACH(hdev, &vhost_devices, entry) {
  58         unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev);
  59         slots_limit = MIN(slots_limit, r);
  60     }
  61     return slots_limit > used_memslots;
  62 }
  63
  64 static void vhost_dev_sync_region(struct vhost_dev *dev,
  65                                   MemoryRegionSection *section,
  66                                   uint64_t mfirst, uint64_t mlast,
  67                                   uint64_t rfirst, uint64_t rlast)
  68 {
  69     vhost_log_chunk_t *log = dev->log->log;
  70
  71     uint64_t start = MAX(mfirst, rfirst);
  72     uint64_t end = MIN(mlast, rlast);
  73     vhost_log_chunk_t *from = log + start / VHOST_LOG_CHUNK;
  74     vhost_log_chunk_t *to = log + end / VHOST_LOG_CHUNK + 1;
  75     uint64_t addr = QEMU_ALIGN_DOWN(start, VHOST_LOG_CHUNK);
  76
  77     if (end < start) {
  78         return;
  79     }
  80     assert(end / VHOST_LOG_CHUNK < dev->log_size);
  81     assert(start / VHOST_LOG_CHUNK < dev->log_size);
  82
  83     for (;from < to; ++from) {
  84         vhost_log_chunk_t log;
  85         /* We first check with non-atomic: much cheaper,
  86          * and we expect non-dirty to be the common case. */
  87         if (!*from) {
  88             addr += VHOST_LOG_CHUNK;
  89             continue;
  90         }
  91         /* Data must be read atomically. We don't really need barrier semantics
  92          * but it's easier to use atomic_* than roll our own. */
  93         log = qatomic_xchg(from, 0);
  94         while (log) {
  95             int bit = ctzl(log);
  96             hwaddr page_addr;
  97             hwaddr section_offset;
  98             hwaddr mr_offset;
  99             page_addr = addr + bit * VHOST_LOG_PAGE;
 100             section_offset = page_addr - section->offset_within_address_space;
 101             mr_offset = section_offset + section->offset_within_region;
 102             memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE);
 103             log &= ~(0x1ull << bit);
 104         }
 105         addr += VHOST_LOG_CHUNK;
 106     }
 107 }
 108
 109 static int vhost_sync_dirty_bitmap(struct vhost_dev *dev,
 110                                    MemoryRegionSection *section,
 111                                    hwaddr first,
 112                                    hwaddr last)
 113 {
 114     int i;
 115     hwaddr start_addr;
 116     hwaddr end_addr;
 117
 118     if (!dev->log_enabled || !dev->started) {
 119         return 0;
 120     }
 121     start_addr = section->offset_within_address_space;
 122     end_addr = range_get_last(start_addr, int128_get64(section->size));
 123     start_addr = MAX(first, start_addr);
 124     end_addr = MIN(last, end_addr);
 125
 126     for (i = 0; i < dev->mem->nregions; ++i) {
 127         struct vhost_memory_region *reg = dev->mem->regions + i;
 128         vhost_dev_sync_region(dev, section, start_addr, end_addr,
 129                               reg->guest_phys_addr,
 130                               range_get_last(reg->guest_phys_addr,
 131                                              reg->memory_size));
 132     }
 133     for (i = 0; i < dev->nvqs; ++i) {
 134         struct vhost_virtqueue *vq = dev->vqs + i;
 135
 136         if (!vq->used_phys && !vq->used_size) {
 137             continue;
 138         }
 139
 140         vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys,
 141                               range_get_last(vq->used_phys, vq->used_size));
 142     }
 143     return 0;
 144 }
 145
 146 static void vhost_log_sync(MemoryListener *listener,
 147                           MemoryRegionSection *section)
 148 {
 149     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 150                                          memory_listener);
 151     vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL);
 152 }
 153
 154 static void vhost_log_sync_range(struct vhost_dev *dev,
 155                                  hwaddr first, hwaddr last)
 156 {
 157     int i;
 158     /* FIXME: this is N^2 in number of sections */
 159     for (i = 0; i < dev->n_mem_sections; ++i) {
 160         MemoryRegionSection *section = &dev->mem_sections[i];
 161         vhost_sync_dirty_bitmap(dev, section, first, last);
 162     }
 163 }
 164
 165 static uint64_t vhost_get_log_size(struct vhost_dev *dev)
 166 {
 167     uint64_t log_size = 0;
 168     int i;
 169     for (i = 0; i < dev->mem->nregions; ++i) {
 170         struct vhost_memory_region *reg = dev->mem->regions + i;
 171         uint64_t last = range_get_last(reg->guest_phys_addr,
 172                                        reg->memory_size);
 173         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 174     }
 175     return log_size;
 176 }
 177
 178 static int vhost_set_backend_type(struct vhost_dev *dev,
 179                                   VhostBackendType backend_type)
 180 {
 181     int r = 0;
 182
 183     switch (backend_type) {
 184 #ifdef CONFIG_VHOST_KERNEL
 185     case VHOST_BACKEND_TYPE_KERNEL:
 186         dev->vhost_ops = &kernel_ops;
 187         break;
 188 #endif
 189 #ifdef CONFIG_VHOST_USER
 190     case VHOST_BACKEND_TYPE_USER:
 191         dev->vhost_ops = &user_ops;
 192         break;
 193 #endif
 194 #ifdef CONFIG_VHOST_VDPA
 195     case VHOST_BACKEND_TYPE_VDPA:
 196         dev->vhost_ops = &vdpa_ops;
 197         break;
 198 #endif
 199     default:
 200         error_report("Unknown vhost backend type");
 201         r = -1;
 202     }
 203
 204     return r;
 205 }
 206
 207 static struct vhost_log *vhost_log_alloc(uint64_t size, bool share)
 208 {
 209     Error *err = NULL;
 210     struct vhost_log *log;
 211     uint64_t logsize = size * sizeof(*(log->log));
 212     int fd = -1;
 213
 214     log = g_new0(struct vhost_log, 1);
 215     if (share) {
 216         log->log = qemu_memfd_alloc("vhost-log", logsize,
 217                                     F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
 218                                     &fd, &err);
 219         if (err) {
 220             error_report_err(err);
 221             g_free(log);
 222             return NULL;
 223         }
 224         memset(log->log, 0, logsize);
 225     } else {
 226         log->log = g_malloc0(logsize);
 227     }
 228
 229     log->size = size;
 230     log->refcnt = 1;
 231     log->fd = fd;
 232
 233     return log;
 234 }
 235
 236 static struct vhost_log *vhost_log_get(uint64_t size, bool share)
 237 {
 238     struct vhost_log *log = share ? vhost_log_shm : vhost_log;
 239
 240     if (!log || log->size != size) {
 241         log = vhost_log_alloc(size, share);
 242         if (share) {
 243             vhost_log_shm = log;
 244         } else {
 245             vhost_log = log;
 246         }
 247     } else {
 248         ++log->refcnt;
 249     }
 250
 251     return log;
 252 }
 253
 254 static void vhost_log_put(struct vhost_dev *dev, bool sync)
 255 {
 256     struct vhost_log *log = dev->log;
 257
 258     if (!log) {
 259         return;
 260     }
 261
 262     --log->refcnt;
 263     if (log->refcnt == 0) {
 264         /* Sync only the range covered by the old log */
 265         if (dev->log_size && sync) {
 266             vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1);
 267         }
 268
 269         if (vhost_log == log) {
 270             g_free(log->log);
 271             vhost_log = NULL;
 272         } else if (vhost_log_shm == log) {
 273             qemu_memfd_free(log->log, log->size * sizeof(*(log->log)),
 274                             log->fd);
 275             vhost_log_shm = NULL;
 276         }
 277
 278         g_free(log);
 279     }
 280
 281     dev->log = NULL;
 282     dev->log_size = 0;
 283 }
 284
 285 static bool vhost_dev_log_is_shared(struct vhost_dev *dev)
 286 {
 287     return dev->vhost_ops->vhost_requires_shm_log &&
 288            dev->vhost_ops->vhost_requires_shm_log(dev);
 289 }
 290
 291 static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size)
 292 {
 293     struct vhost_log *log = vhost_log_get(size, vhost_dev_log_is_shared(dev));
 294     uint64_t log_base = (uintptr_t)log->log;
 295     int r;
 296
 297     /* inform backend of log switching, this must be done before
 298        releasing the current log, to ensure no logging is lost */
 299     r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log);
 300     if (r < 0) {
 301         VHOST_OPS_DEBUG(r, "vhost_set_log_base failed");
 302     }
 303
 304     vhost_log_put(dev, true);
 305     dev->log = log;
 306     dev->log_size = size;
 307 }
 308
 309 static int vhost_dev_has_iommu(struct vhost_dev *dev)
 310 {
 311     VirtIODevice *vdev = dev->vdev;
 312
 313     /*
 314      * For vhost, VIRTIO_F_IOMMU_PLATFORM means the backend support
 315      * incremental memory mapping API via IOTLB API. For platform that
 316      * does not have IOMMU, there's no need to enable this feature
 317      * which may cause unnecessary IOTLB miss/update transactions.
 318      */
 319     return virtio_bus_device_iommu_enabled(vdev) &&
 320            virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
 321 }
 322
 323 static void *vhost_memory_map(struct vhost_dev *dev, hwaddr addr,
 324                               hwaddr *plen, bool is_write)
 325 {
 326     if (!vhost_dev_has_iommu(dev)) {
 327         return cpu_physical_memory_map(addr, plen, is_write);
 328     } else {
 329         return (void *)(uintptr_t)addr;
 330     }
 331 }
 332
 333 static void vhost_memory_unmap(struct vhost_dev *dev, void *buffer,
 334                                hwaddr len, int is_write,
 335                                hwaddr access_len)
 336 {
 337     if (!vhost_dev_has_iommu(dev)) {
 338         cpu_physical_memory_unmap(buffer, len, is_write, access_len);
 339     }
 340 }
 341
 342 static int vhost_verify_ring_part_mapping(void *ring_hva,
 343                                           uint64_t ring_gpa,
 344                                           uint64_t ring_size,
 345                                           void *reg_hva,
 346                                           uint64_t reg_gpa,
 347                                           uint64_t reg_size)
 348 {
 349     uint64_t hva_ring_offset;
 350     uint64_t ring_last = range_get_last(ring_gpa, ring_size);
 351     uint64_t reg_last = range_get_last(reg_gpa, reg_size);
 352
 353     if (ring_last < reg_gpa || ring_gpa > reg_last) {
 354         return 0;
 355     }
 356     /* check that whole ring's is mapped */
 357     if (ring_last > reg_last) {
 358         return -ENOMEM;
 359     }
 360     /* check that ring's MemoryRegion wasn't replaced */
 361     hva_ring_offset = ring_gpa - reg_gpa;
 362     if (ring_hva != reg_hva + hva_ring_offset) {
 363         return -EBUSY;
 364     }
 365
 366     return 0;
 367 }
 368
 369 static int vhost_verify_ring_mappings(struct vhost_dev *dev,
 370                                       void *reg_hva,
 371                                       uint64_t reg_gpa,
 372                                       uint64_t reg_size)
 373 {
 374     int i, j;
 375     int r = 0;
 376     const char *part_name[] = {
 377         "descriptor table",
 378         "available ring",
 379         "used ring"
 380     };
 381
 382     if (vhost_dev_has_iommu(dev)) {
 383         return 0;
 384     }
 385
 386     for (i = 0; i < dev->nvqs; ++i) {
 387         struct vhost_virtqueue *vq = dev->vqs + i;
 388
 389         if (vq->desc_phys == 0) {
 390             continue;
 391         }
 392
 393         j = 0;
 394         r = vhost_verify_ring_part_mapping(
 395                 vq->desc, vq->desc_phys, vq->desc_size,
 396                 reg_hva, reg_gpa, reg_size);
 397         if (r) {
 398             break;
 399         }
 400
 401         j++;
 402         r = vhost_verify_ring_part_mapping(
 403                 vq->avail, vq->avail_phys, vq->avail_size,
 404                 reg_hva, reg_gpa, reg_size);
 405         if (r) {
 406             break;
 407         }
 408
 409         j++;
 410         r = vhost_verify_ring_part_mapping(
 411                 vq->used, vq->used_phys, vq->used_size,
 412                 reg_hva, reg_gpa, reg_size);
 413         if (r) {
 414             break;
 415         }
 416     }
 417
 418     if (r == -ENOMEM) {
 419         error_report("Unable to map %s for ring %d", part_name[j], i);
 420     } else if (r == -EBUSY) {
 421         error_report("%s relocated for ring %d", part_name[j], i);
 422     }
 423     return r;
 424 }
 425
 426 /*
 427  * vhost_section: identify sections needed for vhost access
 428  *
 429  * We only care about RAM sections here (where virtqueue and guest
 430  * internals accessed by virtio might live). If we find one we still
 431  * allow the backend to potentially filter it out of our list.
 432  */
 433 static bool vhost_section(struct vhost_dev *dev, MemoryRegionSection *section)
 434 {
 435     MemoryRegion *mr = section->mr;
 436
 437     if (memory_region_is_ram(mr) && !memory_region_is_rom(mr)) {
 438         uint8_t dirty_mask = memory_region_get_dirty_log_mask(mr);
 439         uint8_t handled_dirty;
 440
 441         /*
 442          * Kernel based vhost doesn't handle any block which is doing
 443          * dirty-tracking other than migration for which it has
 444          * specific logging support. However for TCG the kernel never
 445          * gets involved anyway so we can also ignore it's
 446          * self-modiying code detection flags. However a vhost-user
 447          * client could still confuse a TCG guest if it re-writes
 448          * executable memory that has already been translated.
 449          */
 450         handled_dirty = (1 << DIRTY_MEMORY_MIGRATION) |
 451             (1 << DIRTY_MEMORY_CODE);
 452
 453         if (dirty_mask & ~handled_dirty) {
 454             trace_vhost_reject_section(mr->name, 1);
 455             return false;
 456         }
 457
 458         if (dev->vhost_ops->vhost_backend_mem_section_filter &&
 459             !dev->vhost_ops->vhost_backend_mem_section_filter(dev, section)) {
 460             trace_vhost_reject_section(mr->name, 2);
 461             return false;
 462         }
 463
 464         trace_vhost_section(mr->name);
 465         return true;
 466     } else {
 467         trace_vhost_reject_section(mr->name, 3);
 468         return false;
 469     }
 470 }
 471
 472 static void vhost_begin(MemoryListener *listener)
 473 {
 474     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 475                                          memory_listener);
 476     dev->tmp_sections = NULL;
 477     dev->n_tmp_sections = 0;
 478 }
 479
 480 static void vhost_commit(MemoryListener *listener)
 481 {
 482     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 483                                          memory_listener);
 484     MemoryRegionSection *old_sections;
 485     int n_old_sections;
 486     uint64_t log_size;
 487     size_t regions_size;
 488     int r;
 489     int i;
 490     bool changed = false;
 491
 492     /* Note we can be called before the device is started, but then
 493      * starting the device calls set_mem_table, so we need to have
 494      * built the data structures.
 495      */
 496     old_sections = dev->mem_sections;
 497     n_old_sections = dev->n_mem_sections;
 498     dev->mem_sections = dev->tmp_sections;
 499     dev->n_mem_sections = dev->n_tmp_sections;
 500
 501     if (dev->n_mem_sections != n_old_sections) {
 502         changed = true;
 503     } else {
 504         /* Same size, lets check the contents */
 505         for (int i = 0; i < n_old_sections; i++) {
 506             if (!MemoryRegionSection_eq(&old_sections[i],
 507                                         &dev->mem_sections[i])) {
 508                 changed = true;
 509                 break;
 510             }
 511         }
 512     }
 513
 514     trace_vhost_commit(dev->started, changed);
 515     if (!changed) {
 516         goto out;
 517     }
 518
 519     /* Rebuild the regions list from the new sections list */
 520     regions_size = offsetof(struct vhost_memory, regions) +
 521                        dev->n_mem_sections * sizeof dev->mem->regions[0];
 522     dev->mem = g_realloc(dev->mem, regions_size);
 523     dev->mem->nregions = dev->n_mem_sections;
 524     used_memslots = dev->mem->nregions;
 525     for (i = 0; i < dev->n_mem_sections; i++) {
 526         struct vhost_memory_region *cur_vmr = dev->mem->regions + i;
 527         struct MemoryRegionSection *mrs = dev->mem_sections + i;
 528
 529         cur_vmr->guest_phys_addr = mrs->offset_within_address_space;
 530         cur_vmr->memory_size     = int128_get64(mrs->size);
 531         cur_vmr->userspace_addr  =
 532             (uintptr_t)memory_region_get_ram_ptr(mrs->mr) +
 533             mrs->offset_within_region;
 534         cur_vmr->flags_padding   = 0;
 535     }
 536
 537     if (!dev->started) {
 538         goto out;
 539     }
 540
 541     for (i = 0; i < dev->mem->nregions; i++) {
 542         if (vhost_verify_ring_mappings(dev,
 543                        (void *)(uintptr_t)dev->mem->regions[i].userspace_addr,
 544                        dev->mem->regions[i].guest_phys_addr,
 545                        dev->mem->regions[i].memory_size)) {
 546             error_report("Verify ring failure on region %d", i);
 547             abort();
 548         }
 549     }
 550
 551     if (!dev->log_enabled) {
 552         r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem);
 553         if (r < 0) {
 554             VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed");
 555         }
 556         goto out;
 557     }
 558     log_size = vhost_get_log_size(dev);
 559     /* We allocate an extra 4K bytes to log,
 560      * to reduce the * number of reallocations. */
 561 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
 562     /* To log more, must increase log size before table update. */
 563     if (dev->log_size < log_size) {
 564         vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
 565     }
 566     r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem);
 567     if (r < 0) {
 568         VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed");
 569     }
 570     /* To log less, can only decrease log size after table update. */
 571     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
 572         vhost_dev_log_resize(dev, log_size);
 573     }
 574
 575 out:
 576     /* Deref the old list of sections, this must happen _after_ the
 577      * vhost_set_mem_table to ensure the client isn't still using the
 578      * section we're about to unref.
 579      */
 580     while (n_old_sections--) {
 581         memory_region_unref(old_sections[n_old_sections].mr);
 582     }
 583     g_free(old_sections);
 584     return;
 585 }
 586
 587 /* Adds the section data to the tmp_section structure.
 588  * It relies on the listener calling us in memory address order
 589  * and for each region (via the _add and _nop methods) to
 590  * join neighbours.
 591  */
 592 static void vhost_region_add_section(struct vhost_dev *dev,
 593                                      MemoryRegionSection *section)
 594 {
 595     bool need_add = true;
 596     uint64_t mrs_size = int128_get64(section->size);
 597     uint64_t mrs_gpa = section->offset_within_address_space;
 598     uintptr_t mrs_host = (uintptr_t)memory_region_get_ram_ptr(section->mr) +
 599                          section->offset_within_region;
 600     RAMBlock *mrs_rb = section->mr->ram_block;
 601
 602     trace_vhost_region_add_section(section->mr->name, mrs_gpa, mrs_size,
 603                                    mrs_host);
 604
 605     if (dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER) {
 606         /* Round the section to it's page size */
 607         /* First align the start down to a page boundary */
 608         size_t mrs_page = qemu_ram_pagesize(mrs_rb);
 609         uint64_t alignage = mrs_host & (mrs_page - 1);
 610         if (alignage) {
 611             mrs_host -= alignage;
 612             mrs_size += alignage;
 613             mrs_gpa  -= alignage;
 614         }
 615         /* Now align the size up to a page boundary */
 616         alignage = mrs_size & (mrs_page - 1);
 617         if (alignage) {
 618             mrs_size += mrs_page - alignage;
 619         }
 620         trace_vhost_region_add_section_aligned(section->mr->name, mrs_gpa,
 621                                                mrs_size, mrs_host);
 622     }
 623
 624     if (dev->n_tmp_sections) {
 625         /* Since we already have at least one section, lets see if
 626          * this extends it; since we're scanning in order, we only
 627          * have to look at the last one, and the FlatView that calls
 628          * us shouldn't have overlaps.
 629          */
 630         MemoryRegionSection *prev_sec = dev->tmp_sections +
 631                                                (dev->n_tmp_sections - 1);
 632         uint64_t prev_gpa_start = prev_sec->offset_within_address_space;
 633         uint64_t prev_size = int128_get64(prev_sec->size);
 634         uint64_t prev_gpa_end   = range_get_last(prev_gpa_start, prev_size);
 635         uint64_t prev_host_start =
 636                         (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr) +
 637                         prev_sec->offset_within_region;
 638         uint64_t prev_host_end   = range_get_last(prev_host_start, prev_size);
 639
 640         if (mrs_gpa <= (prev_gpa_end + 1)) {
 641             /* OK, looks like overlapping/intersecting - it's possible that
 642              * the rounding to page sizes has made them overlap, but they should
 643              * match up in the same RAMBlock if they do.
 644              */
 645             if (mrs_gpa < prev_gpa_start) {
 646                 error_report("%s:Section '%s' rounded to %"PRIx64
 647                              " prior to previous '%s' %"PRIx64,
 648                              __func__, section->mr->name, mrs_gpa,
 649                              prev_sec->mr->name, prev_gpa_start);
 650                 /* A way to cleanly fail here would be better */
 651                 return;
 652             }
 653             /* Offset from the start of the previous GPA to this GPA */
 654             size_t offset = mrs_gpa - prev_gpa_start;
 655
 656             if (prev_host_start + offset == mrs_host &&
 657                 section->mr == prev_sec->mr &&
 658                 (!dev->vhost_ops->vhost_backend_can_merge ||
 659                  dev->vhost_ops->vhost_backend_can_merge(dev,
 660                     mrs_host, mrs_size,
 661                     prev_host_start, prev_size))) {
 662                 uint64_t max_end = MAX(prev_host_end, mrs_host + mrs_size);
 663                 need_add = false;
 664                 prev_sec->offset_within_address_space =
 665                     MIN(prev_gpa_start, mrs_gpa);
 666                 prev_sec->offset_within_region =
 667                     MIN(prev_host_start, mrs_host) -
 668                     (uintptr_t)memory_region_get_ram_ptr(prev_sec->mr);
 669                 prev_sec->size = int128_make64(max_end - MIN(prev_host_start,
 670                                                mrs_host));
 671                 trace_vhost_region_add_section_merge(section->mr->name,
 672                                         int128_get64(prev_sec->size),
 673                                         prev_sec->offset_within_address_space,
 674                                         prev_sec->offset_within_region);
 675             } else {
 676                 /* adjoining regions are fine, but overlapping ones with
 677                  * different blocks/offsets shouldn't happen
 678                  */
 679                 if (mrs_gpa != prev_gpa_end + 1) {
 680                     error_report("%s: Overlapping but not coherent sections "
 681                                  "at %"PRIx64,
 682                                  __func__, mrs_gpa);
 683                     return;
 684                 }
 685             }
 686         }
 687     }
 688
 689     if (need_add) {
 690         ++dev->n_tmp_sections;
 691         dev->tmp_sections = g_renew(MemoryRegionSection, dev->tmp_sections,
 692                                     dev->n_tmp_sections);
 693         dev->tmp_sections[dev->n_tmp_sections - 1] = *section;
 694         /* The flatview isn't stable and we don't use it, making it NULL
 695          * means we can memcmp the list.
 696          */
 697         dev->tmp_sections[dev->n_tmp_sections - 1].fv = NULL;
 698         memory_region_ref(section->mr);
 699     }
 700 }
 701
 702 /* Used for both add and nop callbacks */
 703 static void vhost_region_addnop(MemoryListener *listener,
 704                                 MemoryRegionSection *section)
 705 {
 706     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 707                                          memory_listener);
 708
 709     if (!vhost_section(dev, section)) {
 710         return;
 711     }
 712     vhost_region_add_section(dev, section);
 713 }
 714
 715 static void vhost_iommu_unmap_notify(IOMMUNotifier *n, IOMMUTLBEntry *iotlb)
 716 {
 717     struct vhost_iommu *iommu = container_of(n, struct vhost_iommu, n);
 718     struct vhost_dev *hdev = iommu->hdev;
 719     hwaddr iova = iotlb->iova + iommu->iommu_offset;
 720
 721     if (vhost_backend_invalidate_device_iotlb(hdev, iova,
 722                                               iotlb->addr_mask + 1)) {
 723         error_report("Fail to invalidate device iotlb");
 724     }
 725 }
 726
 727 static void vhost_iommu_region_add(MemoryListener *listener,
 728                                    MemoryRegionSection *section)
 729 {
 730     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 731                                          iommu_listener);
 732     struct vhost_iommu *iommu;
 733     Int128 end;
 734     int iommu_idx;
 735     IOMMUMemoryRegion *iommu_mr;
 736     int ret;
 737
 738     if (!memory_region_is_iommu(section->mr)) {
 739         return;
 740     }
 741
 742     iommu_mr = IOMMU_MEMORY_REGION(section->mr);
 743
 744     iommu = g_malloc0(sizeof(*iommu));
 745     end = int128_add(int128_make64(section->offset_within_region),
 746                      section->size);
 747     end = int128_sub(end, int128_one());
 748     iommu_idx = memory_region_iommu_attrs_to_index(iommu_mr,
 749                                                    MEMTXATTRS_UNSPECIFIED);
 750     iommu_notifier_init(&iommu->n, vhost_iommu_unmap_notify,
 751                         IOMMU_NOTIFIER_DEVIOTLB_UNMAP,
 752                         section->offset_within_region,
 753                         int128_get64(end),
 754                         iommu_idx);
 755     iommu->mr = section->mr;
 756     iommu->iommu_offset = section->offset_within_address_space -
 757                           section->offset_within_region;
 758     iommu->hdev = dev;
 759     ret = memory_region_register_iommu_notifier(section->mr, &iommu->n, NULL);
 760     if (ret) {
 761         /*
 762          * Some vIOMMUs do not support dev-iotlb yet.  If so, try to use the
 763          * UNMAP legacy message
 764          */
 765         iommu->n.notifier_flags = IOMMU_NOTIFIER_UNMAP;
 766         memory_region_register_iommu_notifier(section->mr, &iommu->n,
 767                                               &error_fatal);
 768     }
 769     QLIST_INSERT_HEAD(&dev->iommu_list, iommu, iommu_next);
 770     /* TODO: can replay help performance here? */
 771 }
 772
 773 static void vhost_iommu_region_del(MemoryListener *listener,
 774                                    MemoryRegionSection *section)
 775 {
 776     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 777                                          iommu_listener);
 778     struct vhost_iommu *iommu;
 779
 780     if (!memory_region_is_iommu(section->mr)) {
 781         return;
 782     }
 783
 784     QLIST_FOREACH(iommu, &dev->iommu_list, iommu_next) {
 785         if (iommu->mr == section->mr &&
 786             iommu->n.start == section->offset_within_region) {
 787             memory_region_unregister_iommu_notifier(iommu->mr,
 788                                                     &iommu->n);
 789             QLIST_REMOVE(iommu, iommu_next);
 790             g_free(iommu);
 791             break;
 792         }
 793     }
 794 }
 795
 796 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
 797                                     struct vhost_virtqueue *vq,
 798                                     unsigned idx, bool enable_log)
 799 {
 800     struct vhost_vring_addr addr;
 801     int r;
 802     memset(&addr, 0, sizeof(struct vhost_vring_addr));
 803
 804     if (dev->vhost_ops->vhost_vq_get_addr) {
 805         r = dev->vhost_ops->vhost_vq_get_addr(dev, &addr, vq);
 806         if (r < 0) {
 807             VHOST_OPS_DEBUG(r, "vhost_vq_get_addr failed");
 808             return r;
 809         }
 810     } else {
 811         addr.desc_user_addr = (uint64_t)(unsigned long)vq->desc;
 812         addr.avail_user_addr = (uint64_t)(unsigned long)vq->avail;
 813         addr.used_user_addr = (uint64_t)(unsigned long)vq->used;
 814     }
 815     addr.index = idx;
 816     addr.log_guest_addr = vq->used_phys;
 817     addr.flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0;
 818     r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
 819     if (r < 0) {
 820         VHOST_OPS_DEBUG(r, "vhost_set_vring_addr failed");
 821     }
 822     return r;
 823 }
 824
 825 static int vhost_dev_set_features(struct vhost_dev *dev,
 826                                   bool enable_log)
 827 {
 828     uint64_t features = dev->acked_features;
 829     int r;
 830     if (enable_log) {
 831         features |= 0x1ULL << VHOST_F_LOG_ALL;
 832     }
 833     if (!vhost_dev_has_iommu(dev)) {
 834         features &= ~(0x1ULL << VIRTIO_F_IOMMU_PLATFORM);
 835     }
 836     if (dev->vhost_ops->vhost_force_iommu) {
 837         if (dev->vhost_ops->vhost_force_iommu(dev) == true) {
 838             features |= 0x1ULL << VIRTIO_F_IOMMU_PLATFORM;
 839        }
 840     }
 841     r = dev->vhost_ops->vhost_set_features(dev, features);
 842     if (r < 0) {
 843         VHOST_OPS_DEBUG(r, "vhost_set_features failed");
 844         goto out;
 845     }
 846     if (dev->vhost_ops->vhost_set_backend_cap) {
 847         r = dev->vhost_ops->vhost_set_backend_cap(dev);
 848         if (r < 0) {
 849             VHOST_OPS_DEBUG(r, "vhost_set_backend_cap failed");
 850             goto out;
 851         }
 852     }
 853
 854 out:
 855     return r;
 856 }
 857
 858 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 859 {
 860     int r, i, idx;
 861     hwaddr addr;
 862
 863     r = vhost_dev_set_features(dev, enable_log);
 864     if (r < 0) {
 865         goto err_features;
 866     }
 867     for (i = 0; i < dev->nvqs; ++i) {
 868         idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i);
 869         addr = virtio_queue_get_desc_addr(dev->vdev, idx);
 870         if (!addr) {
 871             /*
 872              * The queue might not be ready for start. If this
 873              * is the case there is no reason to continue the process.
 874              * The similar logic is used by the vhost_virtqueue_start()
 875              * routine.
 876              */
 877             continue;
 878         }
 879         r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx,
 880                                      enable_log);
 881         if (r < 0) {
 882             goto err_vq;
 883         }
 884     }
 885     return 0;
 886 err_vq:
 887     for (; i >= 0; --i) {
 888         idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i);
 889         vhost_virtqueue_set_addr(dev, dev->vqs + i, idx,
 890                                  dev->log_enabled);
 891     }
 892     vhost_dev_set_features(dev, dev->log_enabled);
 893 err_features:
 894     return r;
 895 }
 896
 897 static int vhost_migration_log(MemoryListener *listener, bool enable)
 898 {
 899     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 900                                          memory_listener);
 901     int r;
 902     if (enable == dev->log_enabled) {
 903         return 0;
 904     }
 905     if (!dev->started) {
 906         dev->log_enabled = enable;
 907         return 0;
 908     }
 909
 910     r = 0;
 911     if (!enable) {
 912         r = vhost_dev_set_log(dev, false);
 913         if (r < 0) {
 914             goto check_dev_state;
 915         }
 916         vhost_log_put(dev, false);
 917     } else {
 918         vhost_dev_log_resize(dev, vhost_get_log_size(dev));
 919         r = vhost_dev_set_log(dev, true);
 920         if (r < 0) {
 921             goto check_dev_state;
 922         }
 923     }
 924
 925 check_dev_state:
 926     dev->log_enabled = enable;
 927     /*
 928      * vhost-user-* devices could change their state during log
 929      * initialization due to disconnect. So check dev state after
 930      * vhost communication.
 931      */
 932     if (!dev->started) {
 933         /*
 934          * Since device is in the stopped state, it is okay for
 935          * migration. Return success.
 936          */
 937         r = 0;
 938     }
 939     if (r) {
 940         /* An error occurred. */
 941         dev->log_enabled = false;
 942     }
 943
 944     return r;
 945 }
 946
 947 static void vhost_log_global_start(MemoryListener *listener)
 948 {
 949     int r;
 950
 951     r = vhost_migration_log(listener, true);
 952     if (r < 0) {
 953         abort();
 954     }
 955 }
 956
 957 static void vhost_log_global_stop(MemoryListener *listener)
 958 {
 959     int r;
 960
 961     r = vhost_migration_log(listener, false);
 962     if (r < 0) {
 963         abort();
 964     }
 965 }
 966
 967 static void vhost_log_start(MemoryListener *listener,
 968                             MemoryRegionSection *section,
 969                             int old, int new)
 970 {
 971     /* FIXME: implement */
 972 }
 973
 974 static void vhost_log_stop(MemoryListener *listener,
 975                            MemoryRegionSection *section,
 976                            int old, int new)
 977 {
 978     /* FIXME: implement */
 979 }
 980
 981 /* The vhost driver natively knows how to handle the vrings of non
 982  * cross-endian legacy devices and modern devices. Only legacy devices
 983  * exposed to a bi-endian guest may require the vhost driver to use a
 984  * specific endianness.
 985  */
 986 static inline bool vhost_needs_vring_endian(VirtIODevice *vdev)
 987 {
 988     if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
 989         return false;
 990     }
 991 #if HOST_BIG_ENDIAN
 992     return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_LITTLE;
 993 #else
 994     return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG;
 995 #endif
 996 }
 997
 998 static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev,
 999                                                    bool is_big_endian,
1000                                                    int vhost_vq_index)
1001 {
1002     int r;
1003     struct vhost_vring_state s = {
1004         .index = vhost_vq_index,
1005         .num = is_big_endian
1006     };
1007
1008     r = dev->vhost_ops->vhost_set_vring_endian(dev, &s);
1009     if (r < 0) {
1010         VHOST_OPS_DEBUG(r, "vhost_set_vring_endian failed");
1011     }
1012     return r;
1013 }
1014
1015 static int vhost_memory_region_lookup(struct vhost_dev *hdev,
1016                                       uint64_t gpa, uint64_t *uaddr,
1017                                       uint64_t *len)
1018 {
1019     int i;
1020
1021     for (i = 0; i < hdev->mem->nregions; i++) {
1022         struct vhost_memory_region *reg = hdev->mem->regions + i;
1023
1024         if (gpa >= reg->guest_phys_addr &&
1025             reg->guest_phys_addr + reg->memory_size > gpa) {
1026             *uaddr = reg->userspace_addr + gpa - reg->guest_phys_addr;
1027             *len = reg->guest_phys_addr + reg->memory_size - gpa;
1028             return 0;
1029         }
1030     }
1031
1032     return -EFAULT;
1033 }
1034
1035 int vhost_device_iotlb_miss(struct vhost_dev *dev, uint64_t iova, int write)
1036 {
1037     IOMMUTLBEntry iotlb;
1038     uint64_t uaddr, len;
1039     int ret = -EFAULT;
1040
1041     RCU_READ_LOCK_GUARD();
1042
1043     trace_vhost_iotlb_miss(dev, 1);
1044
1045     iotlb = address_space_get_iotlb_entry(dev->vdev->dma_as,
1046                                           iova, write,
1047                                           MEMTXATTRS_UNSPECIFIED);
1048     if (iotlb.target_as != NULL) {
1049         ret = vhost_memory_region_lookup(dev, iotlb.translated_addr,
1050                                          &uaddr, &len);
1051         if (ret) {
1052             trace_vhost_iotlb_miss(dev, 3);
1053             error_report("Fail to lookup the translated address "
1054                          "%"PRIx64, iotlb.translated_addr);
1055             goto out;
1056         }
1057
1058         len = MIN(iotlb.addr_mask + 1, len);
1059         iova = iova & ~iotlb.addr_mask;
1060
1061         ret = vhost_backend_update_device_iotlb(dev, iova, uaddr,
1062                                                 len, iotlb.perm);
1063         if (ret) {
1064             trace_vhost_iotlb_miss(dev, 4);
1065             error_report("Fail to update device iotlb");
1066             goto out;
1067         }
1068     }
1069
1070     trace_vhost_iotlb_miss(dev, 2);
1071
1072 out:
1073     return ret;
1074 }
1075
1076 static int vhost_virtqueue_start(struct vhost_dev *dev,
1077                                 struct VirtIODevice *vdev,
1078                                 struct vhost_virtqueue *vq,
1079                                 unsigned idx)
1080 {
1081     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
1082     VirtioBusState *vbus = VIRTIO_BUS(qbus);
1083     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
1084     hwaddr s, l, a;
1085     int r;
1086     int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx);
1087     struct vhost_vring_file file = {
1088         .index = vhost_vq_index
1089     };
1090     struct vhost_vring_state state = {
1091         .index = vhost_vq_index
1092     };
1093     struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
1094
1095     a = virtio_queue_get_desc_addr(vdev, idx);
1096     if (a == 0) {
1097         /* Queue might not be ready for start */
1098         return 0;
1099     }
1100
1101     vq->num = state.num = virtio_queue_get_num(vdev, idx);
1102     r = dev->vhost_ops->vhost_set_vring_num(dev, &state);
1103     if (r) {
1104         VHOST_OPS_DEBUG(r, "vhost_set_vring_num failed");
1105         return r;
1106     }
1107
1108     state.num = virtio_queue_get_last_avail_idx(vdev, idx);
1109     r = dev->vhost_ops->vhost_set_vring_base(dev, &state);
1110     if (r) {
1111         VHOST_OPS_DEBUG(r, "vhost_set_vring_base failed");
1112         return r;
1113     }
1114
1115     if (vhost_needs_vring_endian(vdev)) {
1116         r = vhost_virtqueue_set_vring_endian_legacy(dev,
1117                                                     virtio_is_big_endian(vdev),
1118                                                     vhost_vq_index);
1119         if (r) {
1120             return r;
1121         }
1122     }
1123
1124     vq->desc_size = s = l = virtio_queue_get_desc_size(vdev, idx);
1125     vq->desc_phys = a;
1126     vq->desc = vhost_memory_map(dev, a, &l, false);
1127     if (!vq->desc || l != s) {
1128         r = -ENOMEM;
1129         goto fail_alloc_desc;
1130     }
1131     vq->avail_size = s = l = virtio_queue_get_avail_size(vdev, idx);
1132     vq->avail_phys = a = virtio_queue_get_avail_addr(vdev, idx);
1133     vq->avail = vhost_memory_map(dev, a, &l, false);
1134     if (!vq->avail || l != s) {
1135         r = -ENOMEM;
1136         goto fail_alloc_avail;
1137     }
1138     vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
1139     vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
1140     vq->used = vhost_memory_map(dev, a, &l, true);
1141     if (!vq->used || l != s) {
1142         r = -ENOMEM;
1143         goto fail_alloc_used;
1144     }
1145
1146     r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);
1147     if (r < 0) {
1148         goto fail_alloc;
1149     }
1150
1151     file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
1152     r = dev->vhost_ops->vhost_set_vring_kick(dev, &file);
1153     if (r) {
1154         VHOST_OPS_DEBUG(r, "vhost_set_vring_kick failed");
1155         goto fail_kick;
1156     }
1157
1158     /* Clear and discard previous events if any. */
1159     event_notifier_test_and_clear(&vq->masked_notifier);
1160
1161     /* Init vring in unmasked state, unless guest_notifier_mask
1162      * will do it later.
1163      */
1164     if (!vdev->use_guest_notifier_mask) {
1165         /* TODO: check and handle errors. */
1166         vhost_virtqueue_mask(dev, vdev, idx, false);
1167     }
1168
1169     if (k->query_guest_notifiers &&
1170         k->query_guest_notifiers(qbus->parent) &&
1171         virtio_queue_vector(vdev, idx) == VIRTIO_NO_VECTOR) {
1172         file.fd = -1;
1173         r = dev->vhost_ops->vhost_set_vring_call(dev, &file);
1174         if (r) {
1175             goto fail_vector;
1176         }
1177     }
1178
1179     return 0;
1180
1181 fail_vector:
1182 fail_kick:
1183 fail_alloc:
1184     vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx),
1185                        0, 0);
1186 fail_alloc_used:
1187     vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx),
1188                        0, 0);
1189 fail_alloc_avail:
1190     vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx),
1191                        0, 0);
1192 fail_alloc_desc:
1193     return r;
1194 }
1195
1196 static void vhost_virtqueue_stop(struct vhost_dev *dev,
1197                                     struct VirtIODevice *vdev,
1198                                     struct vhost_virtqueue *vq,
1199                                     unsigned idx)
1200 {
1201     int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx);
1202     struct vhost_vring_state state = {
1203         .index = vhost_vq_index,
1204     };
1205     int r;
1206
1207     if (virtio_queue_get_desc_addr(vdev, idx) == 0) {
1208         /* Don't stop the virtqueue which might have not been started */
1209         return;
1210     }
1211
1212     r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
1213     if (r < 0) {
1214         VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r);
1215         /* Connection to the backend is broken, so let's sync internal
1216          * last avail idx to the device used idx.
1217          */
1218         virtio_queue_restore_last_avail_idx(vdev, idx);
1219     } else {
1220         virtio_queue_set_last_avail_idx(vdev, idx, state.num);
1221     }
1222     virtio_queue_invalidate_signalled_used(vdev, idx);
1223     virtio_queue_update_used_idx(vdev, idx);
1224
1225     /* In the cross-endian case, we need to reset the vring endianness to
1226      * native as legacy devices expect so by default.
1227      */
1228     if (vhost_needs_vring_endian(vdev)) {
1229         vhost_virtqueue_set_vring_endian_legacy(dev,
1230                                                 !virtio_is_big_endian(vdev),
1231                                                 vhost_vq_index);
1232     }
1233
1234     vhost_memory_unmap(dev, vq->used, virtio_queue_get_used_size(vdev, idx),
1235                        1, virtio_queue_get_used_size(vdev, idx));
1236     vhost_memory_unmap(dev, vq->avail, virtio_queue_get_avail_size(vdev, idx),
1237                        0, virtio_queue_get_avail_size(vdev, idx));
1238     vhost_memory_unmap(dev, vq->desc, virtio_queue_get_desc_size(vdev, idx),
1239                        0, virtio_queue_get_desc_size(vdev, idx));
1240 }
1241
1242 static void vhost_eventfd_add(MemoryListener *listener,
1243                               MemoryRegionSection *section,
1244                               bool match_data, uint64_t data, EventNotifier *e)
1245 {
1246 }
1247
1248 static void vhost_eventfd_del(MemoryListener *listener,
1249                               MemoryRegionSection *section,
1250                               bool match_data, uint64_t data, EventNotifier *e)
1251 {
1252 }
1253
1254 static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev,
1255                                                 int n, uint32_t timeout)
1256 {
1257     int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n);
1258     struct vhost_vring_state state = {
1259         .index = vhost_vq_index,
1260         .num = timeout,
1261     };
1262     int r;
1263
1264     if (!dev->vhost_ops->vhost_set_vring_busyloop_timeout) {
1265         return -EINVAL;
1266     }
1267
1268     r = dev->vhost_ops->vhost_set_vring_busyloop_timeout(dev, &state);
1269     if (r) {
1270         VHOST_OPS_DEBUG(r, "vhost_set_vring_busyloop_timeout failed");
1271         return r;
1272     }
1273
1274     return 0;
1275 }
1276
1277 static int vhost_virtqueue_init(struct vhost_dev *dev,
1278                                 struct vhost_virtqueue *vq, int n)
1279 {
1280     int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n);
1281     struct vhost_vring_file file = {
1282         .index = vhost_vq_index,
1283     };
1284     int r = event_notifier_init(&vq->masked_notifier, 0);
1285     if (r < 0) {
1286         return r;
1287     }
1288
1289     file.fd = event_notifier_get_wfd(&vq->masked_notifier);
1290     r = dev->vhost_ops->vhost_set_vring_call(dev, &file);
1291     if (r) {
1292         VHOST_OPS_DEBUG(r, "vhost_set_vring_call failed");
1293         goto fail_call;
1294     }
1295
1296     vq->dev = dev;
1297
1298     return 0;
1299 fail_call:
1300     event_notifier_cleanup(&vq->masked_notifier);
1301     return r;
1302 }
1303
1304 static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
1305 {
1306     event_notifier_cleanup(&vq->masked_notifier);
1307 }
1308
1309 int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
1310                    VhostBackendType backend_type, uint32_t busyloop_timeout,
1311                    Error **errp)
1312 {
1313     uint64_t features;
1314     int i, r, n_initialized_vqs = 0;
1315
1316     hdev->vdev = NULL;
1317     hdev->migration_blocker = NULL;
1318
1319     r = vhost_set_backend_type(hdev, backend_type);
1320     assert(r >= 0);
1321
1322     r = hdev->vhost_ops->vhost_backend_init(hdev, opaque, errp);
1323     if (r < 0) {
1324         goto fail;
1325     }
1326
1327     r = hdev->vhost_ops->vhost_set_owner(hdev);
1328     if (r < 0) {
1329         error_setg_errno(errp, -r, "vhost_set_owner failed");
1330         goto fail;
1331     }
1332
1333     r = hdev->vhost_ops->vhost_get_features(hdev, &features);
1334     if (r < 0) {
1335         error_setg_errno(errp, -r, "vhost_get_features failed");
1336         goto fail;
1337     }
1338
1339     for (i = 0; i < hdev->nvqs; ++i, ++n_initialized_vqs) {
1340         r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i);
1341         if (r < 0) {
1342             error_setg_errno(errp, -r, "Failed to initialize virtqueue %d", i);
1343             goto fail;
1344         }
1345     }
1346
1347     if (busyloop_timeout) {
1348         for (i = 0; i < hdev->nvqs; ++i) {
1349             r = vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i,
1350                                                      busyloop_timeout);
1351             if (r < 0) {
1352                 error_setg_errno(errp, -r, "Failed to set busyloop timeout");
1353                 goto fail_busyloop;
1354             }
1355         }
1356     }
1357
1358     hdev->features = features;
1359
1360     hdev->memory_listener = (MemoryListener) {
1361         .name = "vhost",
1362         .begin = vhost_begin,
1363         .commit = vhost_commit,
1364         .region_add = vhost_region_addnop,
1365         .region_nop = vhost_region_addnop,
1366         .log_start = vhost_log_start,
1367         .log_stop = vhost_log_stop,
1368         .log_sync = vhost_log_sync,
1369         .log_global_start = vhost_log_global_start,
1370         .log_global_stop = vhost_log_global_stop,
1371         .eventfd_add = vhost_eventfd_add,
1372         .eventfd_del = vhost_eventfd_del,
1373         .priority = 10
1374     };
1375
1376     hdev->iommu_listener = (MemoryListener) {
1377         .name = "vhost-iommu",
1378         .region_add = vhost_iommu_region_add,
1379         .region_del = vhost_iommu_region_del,
1380     };
1381
1382     if (hdev->migration_blocker == NULL) {
1383         if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) {
1384             error_setg(&hdev->migration_blocker,
1385                        "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature.");
1386         } else if (vhost_dev_log_is_shared(hdev) && !qemu_memfd_alloc_check()) {
1387             error_setg(&hdev->migration_blocker,
1388                        "Migration disabled: failed to allocate shared memory");
1389         }
1390     }
1391
1392     if (hdev->migration_blocker != NULL) {
1393         r = migrate_add_blocker(hdev->migration_blocker, errp);
1394         if (r < 0) {
1395             error_free(hdev->migration_blocker);
1396             goto fail_busyloop;
1397         }
1398     }
1399
1400     hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
1401     hdev->n_mem_sections = 0;
1402     hdev->mem_sections = NULL;
1403     hdev->log = NULL;
1404     hdev->log_size = 0;
1405     hdev->log_enabled = false;
1406     hdev->started = false;
1407     memory_listener_register(&hdev->memory_listener, &address_space_memory);
1408     QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
1409
1410     if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
1411         error_setg(errp, "vhost backend memory slots limit is less"
1412                    " than current number of present memory slots");
1413         r = -EINVAL;
1414         goto fail_busyloop;
1415     }
1416
1417     return 0;
1418
1419 fail_busyloop:
1420     if (busyloop_timeout) {
1421         while (--i >= 0) {
1422             vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0);
1423         }
1424     }
1425 fail:
1426     hdev->nvqs = n_initialized_vqs;
1427     vhost_dev_cleanup(hdev);
1428     return r;
1429 }
1430
1431 void vhost_dev_cleanup(struct vhost_dev *hdev)
1432 {
1433     int i;
1434
1435     for (i = 0; i < hdev->nvqs; ++i) {
1436         vhost_virtqueue_cleanup(hdev->vqs + i);
1437     }
1438     if (hdev->mem) {
1439         /* those are only safe after successful init */
1440         memory_listener_unregister(&hdev->memory_listener);
1441         QLIST_REMOVE(hdev, entry);
1442     }
1443     if (hdev->migration_blocker) {
1444         migrate_del_blocker(hdev->migration_blocker);
1445         error_free(hdev->migration_blocker);
1446     }
1447     g_free(hdev->mem);
1448     g_free(hdev->mem_sections);
1449     if (hdev->vhost_ops) {
1450         hdev->vhost_ops->vhost_backend_cleanup(hdev);
1451     }
1452     assert(!hdev->log);
1453
1454     memset(hdev, 0, sizeof(struct vhost_dev));
1455 }
1456
1457 /* Stop processing guest IO notifications in qemu.
1458  * Start processing them in vhost in kernel.
1459  */
1460 int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
1461 {
1462     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
1463     int i, r, e;
1464
1465     /* We will pass the notifiers to the kernel, make sure that QEMU
1466      * doesn't interfere.
1467      */
1468     r = virtio_device_grab_ioeventfd(vdev);
1469     if (r < 0) {
1470         error_report("binding does not support host notifiers");
1471         goto fail;
1472     }
1473
1474     for (i = 0; i < hdev->nvqs; ++i) {
1475         r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
1476                                          true);
1477         if (r < 0) {
1478             error_report("vhost VQ %d notifier binding failed: %d", i, -r);
1479             goto fail_vq;
1480         }
1481     }
1482
1483     return 0;
1484 fail_vq:
1485     while (--i >= 0) {
1486         e = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
1487                                          false);
1488         if (e < 0) {
1489             error_report("vhost VQ %d notifier cleanup error: %d", i, -r);
1490         }
1491         assert (e >= 0);
1492         virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i);
1493     }
1494     virtio_device_release_ioeventfd(vdev);
1495 fail:
1496     return r;
1497 }
1498
1499 /* Stop processing guest IO notifications in vhost.
1500  * Start processing them in qemu.
1501  * This might actually run the qemu handlers right away,
1502  * so virtio in qemu must be completely setup when this is called.
1503  */
1504 void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
1505 {
1506     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
1507     int i, r;
1508
1509     for (i = 0; i < hdev->nvqs; ++i) {
1510         r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
1511                                          false);
1512         if (r < 0) {
1513             error_report("vhost VQ %d notifier cleanup failed: %d", i, -r);
1514         }
1515         assert (r >= 0);
1516         virtio_bus_cleanup_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i);
1517     }
1518     virtio_device_release_ioeventfd(vdev);
1519 }
1520
1521 /* Test and clear event pending status.
1522  * Should be called after unmask to avoid losing events.
1523  */
1524 bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n)
1525 {
1526     struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index;
1527     assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);
1528     return event_notifier_test_and_clear(&vq->masked_notifier);
1529 }
1530
1531 /* Mask/unmask events from this vq. */
1532 void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
1533                          bool mask)
1534 {
1535     struct VirtQueue *vvq = virtio_get_queue(vdev, n);
1536     int r, index = n - hdev->vq_index;
1537     struct vhost_vring_file file;
1538
1539     /* should only be called after backend is connected */
1540     assert(hdev->vhost_ops);
1541
1542     if (mask) {
1543         assert(vdev->use_guest_notifier_mask);
1544         file.fd = event_notifier_get_wfd(&hdev->vqs[index].masked_notifier);
1545     } else {
1546         file.fd = event_notifier_get_wfd(virtio_queue_get_guest_notifier(vvq));
1547     }
1548
1549     file.index = hdev->vhost_ops->vhost_get_vq_index(hdev, n);
1550     r = hdev->vhost_ops->vhost_set_vring_call(hdev, &file);
1551     if (r < 0) {
1552         VHOST_OPS_DEBUG(r, "vhost_set_vring_call failed");
1553     }
1554 }
1555
1556 uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
1557                             uint64_t features)
1558 {
1559     const int *bit = feature_bits;
1560     while (*bit != VHOST_INVALID_FEATURE_BIT) {
1561         uint64_t bit_mask = (1ULL << *bit);
1562         if (!(hdev->features & bit_mask)) {
1563             features &= ~bit_mask;
1564         }
1565         bit++;
1566     }
1567     return features;
1568 }
1569
1570 void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
1571                         uint64_t features)
1572 {
1573     const int *bit = feature_bits;
1574     while (*bit != VHOST_INVALID_FEATURE_BIT) {
1575         uint64_t bit_mask = (1ULL << *bit);
1576         if (features & bit_mask) {
1577             hdev->acked_features |= bit_mask;
1578         }
1579         bit++;
1580     }
1581 }
1582
1583 int vhost_dev_get_config(struct vhost_dev *hdev, uint8_t *config,
1584                          uint32_t config_len, Error **errp)
1585 {
1586     assert(hdev->vhost_ops);
1587
1588     if (hdev->vhost_ops->vhost_get_config) {
1589         return hdev->vhost_ops->vhost_get_config(hdev, config, config_len,
1590                                                  errp);
1591     }
1592
1593     error_setg(errp, "vhost_get_config not implemented");
1594     return -ENOSYS;
1595 }
1596
1597 int vhost_dev_set_config(struct vhost_dev *hdev, const uint8_t *data,
1598                          uint32_t offset, uint32_t size, uint32_t flags)
1599 {
1600     assert(hdev->vhost_ops);
1601
1602     if (hdev->vhost_ops->vhost_set_config) {
1603         return hdev->vhost_ops->vhost_set_config(hdev, data, offset,
1604                                                  size, flags);
1605     }
1606
1607     return -ENOSYS;
1608 }
1609
1610 void vhost_dev_set_config_notifier(struct vhost_dev *hdev,
1611                                    const VhostDevConfigOps *ops)
1612 {
1613     hdev->config_ops = ops;
1614 }
1615
1616 void vhost_dev_free_inflight(struct vhost_inflight *inflight)
1617 {
1618     if (inflight && inflight->addr) {
1619         qemu_memfd_free(inflight->addr, inflight->size, inflight->fd);
1620         inflight->addr = NULL;
1621         inflight->fd = -1;
1622     }
1623 }
1624
1625 static int vhost_dev_resize_inflight(struct vhost_inflight *inflight,
1626                                      uint64_t new_size)
1627 {
1628     Error *err = NULL;
1629     int fd = -1;
1630     void *addr = qemu_memfd_alloc("vhost-inflight", new_size,
1631                                   F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL,
1632                                   &fd, &err);
1633
1634     if (err) {
1635         error_report_err(err);
1636         return -ENOMEM;
1637     }
1638
1639     vhost_dev_free_inflight(inflight);
1640     inflight->offset = 0;
1641     inflight->addr = addr;
1642     inflight->fd = fd;
1643     inflight->size = new_size;
1644
1645     return 0;
1646 }
1647
1648 void vhost_dev_save_inflight(struct vhost_inflight *inflight, QEMUFile *f)
1649 {
1650     if (inflight->addr) {
1651         qemu_put_be64(f, inflight->size);
1652         qemu_put_be16(f, inflight->queue_size);
1653         qemu_put_buffer(f, inflight->addr, inflight->size);
1654     } else {
1655         qemu_put_be64(f, 0);
1656     }
1657 }
1658
1659 int vhost_dev_load_inflight(struct vhost_inflight *inflight, QEMUFile *f)
1660 {
1661     uint64_t size;
1662
1663     size = qemu_get_be64(f);
1664     if (!size) {
1665         return 0;
1666     }
1667
1668     if (inflight->size != size) {
1669         int ret = vhost_dev_resize_inflight(inflight, size);
1670         if (ret < 0) {
1671             return ret;
1672         }
1673     }
1674     inflight->queue_size = qemu_get_be16(f);
1675
1676     qemu_get_buffer(f, inflight->addr, size);
1677
1678     return 0;
1679 }
1680
1681 int vhost_dev_prepare_inflight(struct vhost_dev *hdev, VirtIODevice *vdev)
1682 {
1683     int r;
1684
1685     if (hdev->vhost_ops->vhost_get_inflight_fd == NULL ||
1686         hdev->vhost_ops->vhost_set_inflight_fd == NULL) {
1687         return 0;
1688     }
1689
1690     hdev->vdev = vdev;
1691
1692     r = vhost_dev_set_features(hdev, hdev->log_enabled);
1693     if (r < 0) {
1694         VHOST_OPS_DEBUG(r, "vhost_dev_prepare_inflight failed");
1695         return r;
1696     }
1697
1698     return 0;
1699 }
1700
1701 int vhost_dev_set_inflight(struct vhost_dev *dev,
1702                            struct vhost_inflight *inflight)
1703 {
1704     int r;
1705
1706     if (dev->vhost_ops->vhost_set_inflight_fd && inflight->addr) {
1707         r = dev->vhost_ops->vhost_set_inflight_fd(dev, inflight);
1708         if (r) {
1709             VHOST_OPS_DEBUG(r, "vhost_set_inflight_fd failed");
1710             return r;
1711         }
1712     }
1713
1714     return 0;
1715 }
1716
1717 int vhost_dev_get_inflight(struct vhost_dev *dev, uint16_t queue_size,
1718                            struct vhost_inflight *inflight)
1719 {
1720     int r;
1721
1722     if (dev->vhost_ops->vhost_get_inflight_fd) {
1723         r = dev->vhost_ops->vhost_get_inflight_fd(dev, queue_size, inflight);
1724         if (r) {
1725             VHOST_OPS_DEBUG(r, "vhost_get_inflight_fd failed");
1726             return r;
1727         }
1728     }
1729
1730     return 0;
1731 }
1732
1733 /* Host notifiers must be enabled at this point. */
1734 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
1735 {
1736     int i, r;
1737
1738     /* should only be called after backend is connected */
1739     assert(hdev->vhost_ops);
1740
1741     hdev->started = true;
1742     hdev->vdev = vdev;
1743
1744     r = vhost_dev_set_features(hdev, hdev->log_enabled);
1745     if (r < 0) {
1746         goto fail_features;
1747     }
1748
1749     if (vhost_dev_has_iommu(hdev)) {
1750         memory_listener_register(&hdev->iommu_listener, vdev->dma_as);
1751     }
1752
1753     r = hdev->vhost_ops->vhost_set_mem_table(hdev, hdev->mem);
1754     if (r < 0) {
1755         VHOST_OPS_DEBUG(r, "vhost_set_mem_table failed");
1756         goto fail_mem;
1757     }
1758     for (i = 0; i < hdev->nvqs; ++i) {
1759         r = vhost_virtqueue_start(hdev,
1760                                   vdev,
1761                                   hdev->vqs + i,
1762                                   hdev->vq_index + i);
1763         if (r < 0) {
1764             goto fail_vq;
1765         }
1766     }
1767
1768     if (hdev->log_enabled) {
1769         uint64_t log_base;
1770
1771         hdev->log_size = vhost_get_log_size(hdev);
1772         hdev->log = vhost_log_get(hdev->log_size,
1773                                   vhost_dev_log_is_shared(hdev));
1774         log_base = (uintptr_t)hdev->log->log;
1775         r = hdev->vhost_ops->vhost_set_log_base(hdev,
1776                                                 hdev->log_size ? log_base : 0,
1777                                                 hdev->log);
1778         if (r < 0) {
1779             VHOST_OPS_DEBUG(r, "vhost_set_log_base failed");
1780             goto fail_log;
1781         }
1782     }
1783     if (hdev->vhost_ops->vhost_dev_start) {
1784         r = hdev->vhost_ops->vhost_dev_start(hdev, true);
1785         if (r) {
1786             goto fail_log;
1787         }
1788     }
1789     if (vhost_dev_has_iommu(hdev) &&
1790         hdev->vhost_ops->vhost_set_iotlb_callback) {
1791             hdev->vhost_ops->vhost_set_iotlb_callback(hdev, true);
1792
1793         /* Update used ring information for IOTLB to work correctly,
1794          * vhost-kernel code requires for this.*/
1795         for (i = 0; i < hdev->nvqs; ++i) {
1796             struct vhost_virtqueue *vq = hdev->vqs + i;
1797             vhost_device_iotlb_miss(hdev, vq->used_phys, true);
1798         }
1799     }
1800     return 0;
1801 fail_log:
1802     vhost_log_put(hdev, false);
1803 fail_vq:
1804     while (--i >= 0) {
1805         vhost_virtqueue_stop(hdev,
1806                              vdev,
1807                              hdev->vqs + i,
1808                              hdev->vq_index + i);
1809     }
1810
1811 fail_mem:
1812 fail_features:
1813
1814     hdev->started = false;
1815     return r;
1816 }
1817
1818 /* Host notifiers must be enabled at this point. */
1819 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
1820 {
1821     int i;
1822
1823     /* should only be called after backend is connected */
1824     assert(hdev->vhost_ops);
1825
1826     if (hdev->vhost_ops->vhost_dev_start) {
1827         hdev->vhost_ops->vhost_dev_start(hdev, false);
1828     }
1829     for (i = 0; i < hdev->nvqs; ++i) {
1830         vhost_virtqueue_stop(hdev,
1831                              vdev,
1832                              hdev->vqs + i,
1833                              hdev->vq_index + i);
1834     }
1835
1836     if (vhost_dev_has_iommu(hdev)) {
1837         if (hdev->vhost_ops->vhost_set_iotlb_callback) {
1838             hdev->vhost_ops->vhost_set_iotlb_callback(hdev, false);
1839         }
1840         memory_listener_unregister(&hdev->iommu_listener);
1841     }
1842     vhost_log_put(hdev, true);
1843     hdev->started = false;
1844     hdev->vdev = NULL;
1845 }
1846
1847 int vhost_net_set_backend(struct vhost_dev *hdev,
1848                           struct vhost_vring_file *file)
1849 {
1850     if (hdev->vhost_ops->vhost_net_set_backend) {
1851         return hdev->vhost_ops->vhost_net_set_backend(hdev, file);
1852     }
1853
1854     return -ENOSYS;
1855 }