hw/virtio/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  * 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 <sys/ioctl.h>
  17 #include "hw/virtio/vhost.h"
  18 #include "hw/hw.h"
  19 #include "qemu/atomic.h"
  20 #include "qemu/range.h"
  21 #include <linux/vhost.h>
  22 #include "exec/address-spaces.h"
  23 #include "hw/virtio/virtio-bus.h"
  24
  25 static void vhost_dev_sync_region(struct vhost_dev *dev,
  26                                   MemoryRegionSection *section,
  27                                   uint64_t mfirst, uint64_t mlast,
  28                                   uint64_t rfirst, uint64_t rlast)
  29 {
  30     uint64_t start = MAX(mfirst, rfirst);
  31     uint64_t end = MIN(mlast, rlast);
  32     vhost_log_chunk_t *from = dev->log + start / VHOST_LOG_CHUNK;
  33     vhost_log_chunk_t *to = dev->log + end / VHOST_LOG_CHUNK + 1;
  34     uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK;
  35
  36     if (end < start) {
  37         return;
  38     }
  39     assert(end / VHOST_LOG_CHUNK < dev->log_size);
  40     assert(start / VHOST_LOG_CHUNK < dev->log_size);
  41
  42     for (;from < to; ++from) {
  43         vhost_log_chunk_t log;
  44         int bit;
  45         /* We first check with non-atomic: much cheaper,
  46          * and we expect non-dirty to be the common case. */
  47         if (!*from) {
  48             addr += VHOST_LOG_CHUNK;
  49             continue;
  50         }
  51         /* Data must be read atomically. We don't really need barrier semantics
  52          * but it's easier to use atomic_* than roll our own. */
  53         log = atomic_xchg(from, 0);
  54         while ((bit = sizeof(log) > sizeof(int) ?
  55                 ffsll(log) : ffs(log))) {
  56             hwaddr page_addr;
  57             hwaddr section_offset;
  58             hwaddr mr_offset;
  59             bit -= 1;
  60             page_addr = addr + bit * VHOST_LOG_PAGE;
  61             section_offset = page_addr - section->offset_within_address_space;
  62             mr_offset = section_offset + section->offset_within_region;
  63             memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE);
  64             log &= ~(0x1ull << bit);
  65         }
  66         addr += VHOST_LOG_CHUNK;
  67     }
  68 }
  69
  70 static int vhost_sync_dirty_bitmap(struct vhost_dev *dev,
  71                                    MemoryRegionSection *section,
  72                                    hwaddr first,
  73                                    hwaddr last)
  74 {
  75     int i;
  76     hwaddr start_addr;
  77     hwaddr end_addr;
  78
  79     if (!dev->log_enabled || !dev->started) {
  80         return 0;
  81     }
  82     start_addr = section->offset_within_address_space;
  83     end_addr = range_get_last(start_addr, int128_get64(section->size));
  84     start_addr = MAX(first, start_addr);
  85     end_addr = MIN(last, end_addr);
  86
  87     for (i = 0; i < dev->mem->nregions; ++i) {
  88         struct vhost_memory_region *reg = dev->mem->regions + i;
  89         vhost_dev_sync_region(dev, section, start_addr, end_addr,
  90                               reg->guest_phys_addr,
  91                               range_get_last(reg->guest_phys_addr,
  92                                              reg->memory_size));
  93     }
  94     for (i = 0; i < dev->nvqs; ++i) {
  95         struct vhost_virtqueue *vq = dev->vqs + i;
  96         vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys,
  97                               range_get_last(vq->used_phys, vq->used_size));
  98     }
  99     return 0;
 100 }
 101
 102 static void vhost_log_sync(MemoryListener *listener,
 103                           MemoryRegionSection *section)
 104 {
 105     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 106                                          memory_listener);
 107     vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL);
 108 }
 109
 110 static void vhost_log_sync_range(struct vhost_dev *dev,
 111                                  hwaddr first, hwaddr last)
 112 {
 113     int i;
 114     /* FIXME: this is N^2 in number of sections */
 115     for (i = 0; i < dev->n_mem_sections; ++i) {
 116         MemoryRegionSection *section = &dev->mem_sections[i];
 117         vhost_sync_dirty_bitmap(dev, section, first, last);
 118     }
 119 }
 120
 121 /* Assign/unassign. Keep an unsorted array of non-overlapping
 122  * memory regions in dev->mem. */
 123 static void vhost_dev_unassign_memory(struct vhost_dev *dev,
 124                                       uint64_t start_addr,
 125                                       uint64_t size)
 126 {
 127     int from, to, n = dev->mem->nregions;
 128     /* Track overlapping/split regions for sanity checking. */
 129     int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0;
 130
 131     for (from = 0, to = 0; from < n; ++from, ++to) {
 132         struct vhost_memory_region *reg = dev->mem->regions + to;
 133         uint64_t reglast;
 134         uint64_t memlast;
 135         uint64_t change;
 136
 137         /* clone old region */
 138         if (to != from) {
 139             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 140         }
 141
 142         /* No overlap is simple */
 143         if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size,
 144                             start_addr, size)) {
 145             continue;
 146         }
 147
 148         /* Split only happens if supplied region
 149          * is in the middle of an existing one. Thus it can not
 150          * overlap with any other existing region. */
 151         assert(!split);
 152
 153         reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 154         memlast = range_get_last(start_addr, size);
 155
 156         /* Remove whole region */
 157         if (start_addr <= reg->guest_phys_addr && memlast >= reglast) {
 158             --dev->mem->nregions;
 159             --to;
 160             ++overlap_middle;
 161             continue;
 162         }
 163
 164         /* Shrink region */
 165         if (memlast >= reglast) {
 166             reg->memory_size = start_addr - reg->guest_phys_addr;
 167             assert(reg->memory_size);
 168             assert(!overlap_end);
 169             ++overlap_end;
 170             continue;
 171         }
 172
 173         /* Shift region */
 174         if (start_addr <= reg->guest_phys_addr) {
 175             change = memlast + 1 - reg->guest_phys_addr;
 176             reg->memory_size -= change;
 177             reg->guest_phys_addr += change;
 178             reg->userspace_addr += change;
 179             assert(reg->memory_size);
 180             assert(!overlap_start);
 181             ++overlap_start;
 182             continue;
 183         }
 184
 185         /* This only happens if supplied region
 186          * is in the middle of an existing one. Thus it can not
 187          * overlap with any other existing region. */
 188         assert(!overlap_start);
 189         assert(!overlap_end);
 190         assert(!overlap_middle);
 191         /* Split region: shrink first part, shift second part. */
 192         memcpy(dev->mem->regions + n, reg, sizeof *reg);
 193         reg->memory_size = start_addr - reg->guest_phys_addr;
 194         assert(reg->memory_size);
 195         change = memlast + 1 - reg->guest_phys_addr;
 196         reg = dev->mem->regions + n;
 197         reg->memory_size -= change;
 198         assert(reg->memory_size);
 199         reg->guest_phys_addr += change;
 200         reg->userspace_addr += change;
 201         /* Never add more than 1 region */
 202         assert(dev->mem->nregions == n);
 203         ++dev->mem->nregions;
 204         ++split;
 205     }
 206 }
 207
 208 /* Called after unassign, so no regions overlap the given range. */
 209 static void vhost_dev_assign_memory(struct vhost_dev *dev,
 210                                     uint64_t start_addr,
 211                                     uint64_t size,
 212                                     uint64_t uaddr)
 213 {
 214     int from, to;
 215     struct vhost_memory_region *merged = NULL;
 216     for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) {
 217         struct vhost_memory_region *reg = dev->mem->regions + to;
 218         uint64_t prlast, urlast;
 219         uint64_t pmlast, umlast;
 220         uint64_t s, e, u;
 221
 222         /* clone old region */
 223         if (to != from) {
 224             memcpy(reg, dev->mem->regions + from, sizeof *reg);
 225         }
 226         prlast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 227         pmlast = range_get_last(start_addr, size);
 228         urlast = range_get_last(reg->userspace_addr, reg->memory_size);
 229         umlast = range_get_last(uaddr, size);
 230
 231         /* check for overlapping regions: should never happen. */
 232         assert(prlast < start_addr || pmlast < reg->guest_phys_addr);
 233         /* Not an adjacent or overlapping region - do not merge. */
 234         if ((prlast + 1 != start_addr || urlast + 1 != uaddr) &&
 235             (pmlast + 1 != reg->guest_phys_addr ||
 236              umlast + 1 != reg->userspace_addr)) {
 237             continue;
 238         }
 239
 240         if (merged) {
 241             --to;
 242             assert(to >= 0);
 243         } else {
 244             merged = reg;
 245         }
 246         u = MIN(uaddr, reg->userspace_addr);
 247         s = MIN(start_addr, reg->guest_phys_addr);
 248         e = MAX(pmlast, prlast);
 249         uaddr = merged->userspace_addr = u;
 250         start_addr = merged->guest_phys_addr = s;
 251         size = merged->memory_size = e - s + 1;
 252         assert(merged->memory_size);
 253     }
 254
 255     if (!merged) {
 256         struct vhost_memory_region *reg = dev->mem->regions + to;
 257         memset(reg, 0, sizeof *reg);
 258         reg->memory_size = size;
 259         assert(reg->memory_size);
 260         reg->guest_phys_addr = start_addr;
 261         reg->userspace_addr = uaddr;
 262         ++to;
 263     }
 264     assert(to <= dev->mem->nregions + 1);
 265     dev->mem->nregions = to;
 266 }
 267
 268 static uint64_t vhost_get_log_size(struct vhost_dev *dev)
 269 {
 270     uint64_t log_size = 0;
 271     int i;
 272     for (i = 0; i < dev->mem->nregions; ++i) {
 273         struct vhost_memory_region *reg = dev->mem->regions + i;
 274         uint64_t last = range_get_last(reg->guest_phys_addr,
 275                                        reg->memory_size);
 276         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 277     }
 278     for (i = 0; i < dev->nvqs; ++i) {
 279         struct vhost_virtqueue *vq = dev->vqs + i;
 280         uint64_t last = vq->used_phys + vq->used_size - 1;
 281         log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1);
 282     }
 283     return log_size;
 284 }
 285
 286 static inline void vhost_dev_log_resize(struct vhost_dev* dev, uint64_t size)
 287 {
 288     vhost_log_chunk_t *log;
 289     uint64_t log_base;
 290     int r;
 291
 292     log = g_malloc0(size * sizeof *log);
 293     log_base = (uint64_t)(unsigned long)log;
 294     r = ioctl(dev->control, VHOST_SET_LOG_BASE, &log_base);
 295     assert(r >= 0);
 296     /* Sync only the range covered by the old log */
 297     if (dev->log_size) {
 298         vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1);
 299     }
 300     if (dev->log) {
 301         g_free(dev->log);
 302     }
 303     dev->log = log;
 304     dev->log_size = size;
 305 }
 306
 307 static int vhost_verify_ring_mappings(struct vhost_dev *dev,
 308                                       uint64_t start_addr,
 309                                       uint64_t size)
 310 {
 311     int i;
 312     for (i = 0; i < dev->nvqs; ++i) {
 313         struct vhost_virtqueue *vq = dev->vqs + i;
 314         hwaddr l;
 315         void *p;
 316
 317         if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) {
 318             continue;
 319         }
 320         l = vq->ring_size;
 321         p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
 322         if (!p || l != vq->ring_size) {
 323             fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
 324             return -ENOMEM;
 325         }
 326         if (p != vq->ring) {
 327             fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
 328             return -EBUSY;
 329         }
 330         cpu_physical_memory_unmap(p, l, 0, 0);
 331     }
 332     return 0;
 333 }
 334
 335 static struct vhost_memory_region *vhost_dev_find_reg(struct vhost_dev *dev,
 336                                                       uint64_t start_addr,
 337                                                       uint64_t size)
 338 {
 339     int i, n = dev->mem->nregions;
 340     for (i = 0; i < n; ++i) {
 341         struct vhost_memory_region *reg = dev->mem->regions + i;
 342         if (ranges_overlap(reg->guest_phys_addr, reg->memory_size,
 343                            start_addr, size)) {
 344             return reg;
 345         }
 346     }
 347     return NULL;
 348 }
 349
 350 static bool vhost_dev_cmp_memory(struct vhost_dev *dev,
 351                                  uint64_t start_addr,
 352                                  uint64_t size,
 353                                  uint64_t uaddr)
 354 {
 355     struct vhost_memory_region *reg = vhost_dev_find_reg(dev, start_addr, size);
 356     uint64_t reglast;
 357     uint64_t memlast;
 358
 359     if (!reg) {
 360         return true;
 361     }
 362
 363     reglast = range_get_last(reg->guest_phys_addr, reg->memory_size);
 364     memlast = range_get_last(start_addr, size);
 365
 366     /* Need to extend region? */
 367     if (start_addr < reg->guest_phys_addr || memlast > reglast) {
 368         return true;
 369     }
 370     /* userspace_addr changed? */
 371     return uaddr != reg->userspace_addr + start_addr - reg->guest_phys_addr;
 372 }
 373
 374 static void vhost_set_memory(MemoryListener *listener,
 375                              MemoryRegionSection *section,
 376                              bool add)
 377 {
 378     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 379                                          memory_listener);
 380     hwaddr start_addr = section->offset_within_address_space;
 381     ram_addr_t size = int128_get64(section->size);
 382     bool log_dirty = memory_region_is_logging(section->mr);
 383     int s = offsetof(struct vhost_memory, regions) +
 384         (dev->mem->nregions + 1) * sizeof dev->mem->regions[0];
 385     void *ram;
 386
 387     dev->mem = g_realloc(dev->mem, s);
 388
 389     if (log_dirty) {
 390         add = false;
 391     }
 392
 393     assert(size);
 394
 395     /* Optimize no-change case. At least cirrus_vga does this a lot at this time. */
 396     ram = memory_region_get_ram_ptr(section->mr) + section->offset_within_region;
 397     if (add) {
 398         if (!vhost_dev_cmp_memory(dev, start_addr, size, (uintptr_t)ram)) {
 399             /* Region exists with same address. Nothing to do. */
 400             return;
 401         }
 402     } else {
 403         if (!vhost_dev_find_reg(dev, start_addr, size)) {
 404             /* Removing region that we don't access. Nothing to do. */
 405             return;
 406         }
 407     }
 408
 409     vhost_dev_unassign_memory(dev, start_addr, size);
 410     if (add) {
 411         /* Add given mapping, merging adjacent regions if any */
 412         vhost_dev_assign_memory(dev, start_addr, size, (uintptr_t)ram);
 413     } else {
 414         /* Remove old mapping for this memory, if any. */
 415         vhost_dev_unassign_memory(dev, start_addr, size);
 416     }
 417     dev->mem_changed_start_addr = MIN(dev->mem_changed_start_addr, start_addr);
 418     dev->mem_changed_end_addr = MAX(dev->mem_changed_end_addr, start_addr + size - 1);
 419     dev->memory_changed = true;
 420 }
 421
 422 static bool vhost_section(MemoryRegionSection *section)
 423 {
 424     return memory_region_is_ram(section->mr);
 425 }
 426
 427 static void vhost_begin(MemoryListener *listener)
 428 {
 429     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 430                                          memory_listener);
 431     dev->mem_changed_end_addr = 0;
 432     dev->mem_changed_start_addr = -1;
 433 }
 434
 435 static void vhost_commit(MemoryListener *listener)
 436 {
 437     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 438                                          memory_listener);
 439     hwaddr start_addr = 0;
 440     ram_addr_t size = 0;
 441     uint64_t log_size;
 442     int r;
 443
 444     if (!dev->memory_changed) {
 445         return;
 446     }
 447     if (!dev->started) {
 448         return;
 449     }
 450     if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) {
 451         return;
 452     }
 453
 454     if (dev->started) {
 455         start_addr = dev->mem_changed_start_addr;
 456         size = dev->mem_changed_end_addr - dev->mem_changed_start_addr + 1;
 457
 458         r = vhost_verify_ring_mappings(dev, start_addr, size);
 459         assert(r >= 0);
 460     }
 461
 462     if (!dev->log_enabled) {
 463         r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 464         assert(r >= 0);
 465         dev->memory_changed = false;
 466         return;
 467     }
 468     log_size = vhost_get_log_size(dev);
 469     /* We allocate an extra 4K bytes to log,
 470      * to reduce the * number of reallocations. */
 471 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log)
 472     /* To log more, must increase log size before table update. */
 473     if (dev->log_size < log_size) {
 474         vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
 475     }
 476     r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
 477     assert(r >= 0);
 478     /* To log less, can only decrease log size after table update. */
 479     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
 480         vhost_dev_log_resize(dev, log_size);
 481     }
 482     dev->memory_changed = false;
 483 }
 484
 485 static void vhost_region_add(MemoryListener *listener,
 486                              MemoryRegionSection *section)
 487 {
 488     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 489                                          memory_listener);
 490
 491     if (!vhost_section(section)) {
 492         return;
 493     }
 494
 495     ++dev->n_mem_sections;
 496     dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections,
 497                                 dev->n_mem_sections);
 498     dev->mem_sections[dev->n_mem_sections - 1] = *section;
 499     memory_region_ref(section->mr);
 500     vhost_set_memory(listener, section, true);
 501 }
 502
 503 static void vhost_region_del(MemoryListener *listener,
 504                              MemoryRegionSection *section)
 505 {
 506     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 507                                          memory_listener);
 508     int i;
 509
 510     if (!vhost_section(section)) {
 511         return;
 512     }
 513
 514     vhost_set_memory(listener, section, false);
 515     memory_region_unref(section->mr);
 516     for (i = 0; i < dev->n_mem_sections; ++i) {
 517         if (dev->mem_sections[i].offset_within_address_space
 518             == section->offset_within_address_space) {
 519             --dev->n_mem_sections;
 520             memmove(&dev->mem_sections[i], &dev->mem_sections[i+1],
 521                     (dev->n_mem_sections - i) * sizeof(*dev->mem_sections));
 522             break;
 523         }
 524     }
 525 }
 526
 527 static void vhost_region_nop(MemoryListener *listener,
 528                              MemoryRegionSection *section)
 529 {
 530 }
 531
 532 static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
 533                                     struct vhost_virtqueue *vq,
 534                                     unsigned idx, bool enable_log)
 535 {
 536     struct vhost_vring_addr addr = {
 537         .index = idx,
 538         .desc_user_addr = (uint64_t)(unsigned long)vq->desc,
 539         .avail_user_addr = (uint64_t)(unsigned long)vq->avail,
 540         .used_user_addr = (uint64_t)(unsigned long)vq->used,
 541         .log_guest_addr = vq->used_phys,
 542         .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0,
 543     };
 544     int r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr);
 545     if (r < 0) {
 546         return -errno;
 547     }
 548     return 0;
 549 }
 550
 551 static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
 552 {
 553     uint64_t features = dev->acked_features;
 554     int r;
 555     if (enable_log) {
 556         features |= 0x1 << VHOST_F_LOG_ALL;
 557     }
 558     r = ioctl(dev->control, VHOST_SET_FEATURES, &features);
 559     return r < 0 ? -errno : 0;
 560 }
 561
 562 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 563 {
 564     int r, t, i;
 565     r = vhost_dev_set_features(dev, enable_log);
 566     if (r < 0) {
 567         goto err_features;
 568     }
 569     for (i = 0; i < dev->nvqs; ++i) {
 570         r = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 571                                      enable_log);
 572         if (r < 0) {
 573             goto err_vq;
 574         }
 575     }
 576     return 0;
 577 err_vq:
 578     for (; i >= 0; --i) {
 579         t = vhost_virtqueue_set_addr(dev, dev->vqs + i, i,
 580                                      dev->log_enabled);
 581         assert(t >= 0);
 582     }
 583     t = vhost_dev_set_features(dev, dev->log_enabled);
 584     assert(t >= 0);
 585 err_features:
 586     return r;
 587 }
 588
 589 static int vhost_migration_log(MemoryListener *listener, int enable)
 590 {
 591     struct vhost_dev *dev = container_of(listener, struct vhost_dev,
 592                                          memory_listener);
 593     int r;
 594     if (!!enable == dev->log_enabled) {
 595         return 0;
 596     }
 597     if (!dev->started) {
 598         dev->log_enabled = enable;
 599         return 0;
 600     }
 601     if (!enable) {
 602         r = vhost_dev_set_log(dev, false);
 603         if (r < 0) {
 604             return r;
 605         }
 606         if (dev->log) {
 607             g_free(dev->log);
 608         }
 609         dev->log = NULL;
 610         dev->log_size = 0;
 611     } else {
 612         vhost_dev_log_resize(dev, vhost_get_log_size(dev));
 613         r = vhost_dev_set_log(dev, true);
 614         if (r < 0) {
 615             return r;
 616         }
 617     }
 618     dev->log_enabled = enable;
 619     return 0;
 620 }
 621
 622 static void vhost_log_global_start(MemoryListener *listener)
 623 {
 624     int r;
 625
 626     r = vhost_migration_log(listener, true);
 627     if (r < 0) {
 628         abort();
 629     }
 630 }
 631
 632 static void vhost_log_global_stop(MemoryListener *listener)
 633 {
 634     int r;
 635
 636     r = vhost_migration_log(listener, false);
 637     if (r < 0) {
 638         abort();
 639     }
 640 }
 641
 642 static void vhost_log_start(MemoryListener *listener,
 643                             MemoryRegionSection *section)
 644 {
 645     /* FIXME: implement */
 646 }
 647
 648 static void vhost_log_stop(MemoryListener *listener,
 649                            MemoryRegionSection *section)
 650 {
 651     /* FIXME: implement */
 652 }
 653
 654 static int vhost_virtqueue_start(struct vhost_dev *dev,
 655                                 struct VirtIODevice *vdev,
 656                                 struct vhost_virtqueue *vq,
 657                                 unsigned idx)
 658 {
 659     hwaddr s, l, a;
 660     int r;
 661     int vhost_vq_index = idx - dev->vq_index;
 662     struct vhost_vring_file file = {
 663         .index = vhost_vq_index
 664     };
 665     struct vhost_vring_state state = {
 666         .index = vhost_vq_index
 667     };
 668     struct VirtQueue *vvq = virtio_get_queue(vdev, idx);
 669
 670     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
 671
 672     vq->num = state.num = virtio_queue_get_num(vdev, idx);
 673     r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state);
 674     if (r) {
 675         return -errno;
 676     }
 677
 678     state.num = virtio_queue_get_last_avail_idx(vdev, idx);
 679     r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state);
 680     if (r) {
 681         return -errno;
 682     }
 683
 684     s = l = virtio_queue_get_desc_size(vdev, idx);
 685     a = virtio_queue_get_desc_addr(vdev, idx);
 686     vq->desc = cpu_physical_memory_map(a, &l, 0);
 687     if (!vq->desc || l != s) {
 688         r = -ENOMEM;
 689         goto fail_alloc_desc;
 690     }
 691     s = l = virtio_queue_get_avail_size(vdev, idx);
 692     a = virtio_queue_get_avail_addr(vdev, idx);
 693     vq->avail = cpu_physical_memory_map(a, &l, 0);
 694     if (!vq->avail || l != s) {
 695         r = -ENOMEM;
 696         goto fail_alloc_avail;
 697     }
 698     vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx);
 699     vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx);
 700     vq->used = cpu_physical_memory_map(a, &l, 1);
 701     if (!vq->used || l != s) {
 702         r = -ENOMEM;
 703         goto fail_alloc_used;
 704     }
 705
 706     vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx);
 707     vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx);
 708     vq->ring = cpu_physical_memory_map(a, &l, 1);
 709     if (!vq->ring || l != s) {
 710         r = -ENOMEM;
 711         goto fail_alloc_ring;
 712     }
 713
 714     r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled);
 715     if (r < 0) {
 716         r = -errno;
 717         goto fail_alloc;
 718     }
 719
 720     file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq));
 721     r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file);
 722     if (r) {
 723         r = -errno;
 724         goto fail_kick;
 725     }
 726
 727     /* Clear and discard previous events if any. */
 728     event_notifier_test_and_clear(&vq->masked_notifier);
 729
 730     return 0;
 731
 732 fail_kick:
 733 fail_alloc:
 734     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 735                               0, 0);
 736 fail_alloc_ring:
 737     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 738                               0, 0);
 739 fail_alloc_used:
 740     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 741                               0, 0);
 742 fail_alloc_avail:
 743     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 744                               0, 0);
 745 fail_alloc_desc:
 746     return r;
 747 }
 748
 749 static void vhost_virtqueue_stop(struct vhost_dev *dev,
 750                                     struct VirtIODevice *vdev,
 751                                     struct vhost_virtqueue *vq,
 752                                     unsigned idx)
 753 {
 754     struct vhost_vring_state state = {
 755         .index = idx - dev->vq_index
 756     };
 757     int r;
 758     assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
 759     r = ioctl(dev->control, VHOST_GET_VRING_BASE, &state);
 760     if (r < 0) {
 761         fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
 762         fflush(stderr);
 763     }
 764     virtio_queue_set_last_avail_idx(vdev, idx, state.num);
 765     virtio_queue_invalidate_signalled_used(vdev, idx);
 766     assert (r >= 0);
 767     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
 768                               0, virtio_queue_get_ring_size(vdev, idx));
 769     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
 770                               1, virtio_queue_get_used_size(vdev, idx));
 771     cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx),
 772                               0, virtio_queue_get_avail_size(vdev, idx));
 773     cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx),
 774                               0, virtio_queue_get_desc_size(vdev, idx));
 775 }
 776
 777 static void vhost_eventfd_add(MemoryListener *listener,
 778                               MemoryRegionSection *section,
 779                               bool match_data, uint64_t data, EventNotifier *e)
 780 {
 781 }
 782
 783 static void vhost_eventfd_del(MemoryListener *listener,
 784                               MemoryRegionSection *section,
 785                               bool match_data, uint64_t data, EventNotifier *e)
 786 {
 787 }
 788
 789 static int vhost_virtqueue_init(struct vhost_dev *dev,
 790                                 struct vhost_virtqueue *vq, int n)
 791 {
 792     struct vhost_vring_file file = {
 793         .index = n,
 794     };
 795     int r = event_notifier_init(&vq->masked_notifier, 0);
 796     if (r < 0) {
 797         return r;
 798     }
 799
 800     file.fd = event_notifier_get_fd(&vq->masked_notifier);
 801     r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file);
 802     if (r) {
 803         r = -errno;
 804         goto fail_call;
 805     }
 806     return 0;
 807 fail_call:
 808     event_notifier_cleanup(&vq->masked_notifier);
 809     return r;
 810 }
 811
 812 static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
 813 {
 814     event_notifier_cleanup(&vq->masked_notifier);
 815 }
 816
 817 int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
 818                    bool force)
 819 {
 820     uint64_t features;
 821     int i, r;
 822     if (devfd >= 0) {
 823         hdev->control = devfd;
 824     } else {
 825         hdev->control = open(devpath, O_RDWR);
 826         if (hdev->control < 0) {
 827             return -errno;
 828         }
 829     }
 830     r = ioctl(hdev->control, VHOST_SET_OWNER, NULL);
 831     if (r < 0) {
 832         goto fail;
 833     }
 834
 835     r = ioctl(hdev->control, VHOST_GET_FEATURES, &features);
 836     if (r < 0) {
 837         goto fail;
 838     }
 839
 840     for (i = 0; i < hdev->nvqs; ++i) {
 841         r = vhost_virtqueue_init(hdev, hdev->vqs + i, i);
 842         if (r < 0) {
 843             goto fail_vq;
 844         }
 845     }
 846     hdev->features = features;
 847
 848     hdev->memory_listener = (MemoryListener) {
 849         .begin = vhost_begin,
 850         .commit = vhost_commit,
 851         .region_add = vhost_region_add,
 852         .region_del = vhost_region_del,
 853         .region_nop = vhost_region_nop,
 854         .log_start = vhost_log_start,
 855         .log_stop = vhost_log_stop,
 856         .log_sync = vhost_log_sync,
 857         .log_global_start = vhost_log_global_start,
 858         .log_global_stop = vhost_log_global_stop,
 859         .eventfd_add = vhost_eventfd_add,
 860         .eventfd_del = vhost_eventfd_del,
 861         .priority = 10
 862     };
 863     hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
 864     hdev->n_mem_sections = 0;
 865     hdev->mem_sections = NULL;
 866     hdev->log = NULL;
 867     hdev->log_size = 0;
 868     hdev->log_enabled = false;
 869     hdev->started = false;
 870     hdev->memory_changed = false;
 871     memory_listener_register(&hdev->memory_listener, &address_space_memory);
 872     hdev->force = force;
 873     return 0;
 874 fail_vq:
 875     while (--i >= 0) {
 876         vhost_virtqueue_cleanup(hdev->vqs + i);
 877     }
 878 fail:
 879     r = -errno;
 880     close(hdev->control);
 881     return r;
 882 }
 883
 884 void vhost_dev_cleanup(struct vhost_dev *hdev)
 885 {
 886     int i;
 887     for (i = 0; i < hdev->nvqs; ++i) {
 888         vhost_virtqueue_cleanup(hdev->vqs + i);
 889     }
 890     memory_listener_unregister(&hdev->memory_listener);
 891     g_free(hdev->mem);
 892     g_free(hdev->mem_sections);
 893     close(hdev->control);
 894 }
 895
 896 bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev)
 897 {
 898     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 899     VirtioBusState *vbus = VIRTIO_BUS(qbus);
 900     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
 901
 902     return !k->query_guest_notifiers ||
 903            k->query_guest_notifiers(qbus->parent) ||
 904            hdev->force;
 905 }
 906
 907 /* Stop processing guest IO notifications in qemu.
 908  * Start processing them in vhost in kernel.
 909  */
 910 int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
 911 {
 912     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 913     VirtioBusState *vbus = VIRTIO_BUS(qbus);
 914     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
 915     int i, r;
 916     if (!k->set_host_notifier) {
 917         fprintf(stderr, "binding does not support host notifiers\n");
 918         r = -ENOSYS;
 919         goto fail;
 920     }
 921
 922     for (i = 0; i < hdev->nvqs; ++i) {
 923         r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, true);
 924         if (r < 0) {
 925             fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r);
 926             goto fail_vq;
 927         }
 928     }
 929
 930     return 0;
 931 fail_vq:
 932     while (--i >= 0) {
 933         r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false);
 934         if (r < 0) {
 935             fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r);
 936             fflush(stderr);
 937         }
 938         assert (r >= 0);
 939     }
 940 fail:
 941     return r;
 942 }
 943
 944 /* Stop processing guest IO notifications in vhost.
 945  * Start processing them in qemu.
 946  * This might actually run the qemu handlers right away,
 947  * so virtio in qemu must be completely setup when this is called.
 948  */
 949 void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
 950 {
 951     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
 952     VirtioBusState *vbus = VIRTIO_BUS(qbus);
 953     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
 954     int i, r;
 955
 956     for (i = 0; i < hdev->nvqs; ++i) {
 957         r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false);
 958         if (r < 0) {
 959             fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r);
 960             fflush(stderr);
 961         }
 962         assert (r >= 0);
 963     }
 964 }
 965
 966 /* Test and clear event pending status.
 967  * Should be called after unmask to avoid losing events.
 968  */
 969 bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n)
 970 {
 971     struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index;
 972     assert(hdev->started);
 973     assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);
 974     return event_notifier_test_and_clear(&vq->masked_notifier);
 975 }
 976
 977 /* Mask/unmask events from this vq. */
 978 void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
 979                          bool mask)
 980 {
 981     struct VirtQueue *vvq = virtio_get_queue(vdev, n);
 982     int r, index = n - hdev->vq_index;
 983
 984     assert(hdev->started);
 985     assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs);
 986
 987     struct vhost_vring_file file = {
 988         .index = index
 989     };
 990     if (mask) {
 991         file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier);
 992     } else {
 993         file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq));
 994     }
 995     r = ioctl(hdev->control, VHOST_SET_VRING_CALL, &file);
 996     assert(r >= 0);
 997 }
 998
 999 /* Host notifiers must be enabled at this point. */
1000 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
1001 {
1002     int i, r;
1003
1004     hdev->started = true;
1005
1006     r = vhost_dev_set_features(hdev, hdev->log_enabled);
1007     if (r < 0) {
1008         goto fail_features;
1009     }
1010     r = ioctl(hdev->control, VHOST_SET_MEM_TABLE, hdev->mem);
1011     if (r < 0) {
1012         r = -errno;
1013         goto fail_mem;
1014     }
1015     for (i = 0; i < hdev->nvqs; ++i) {
1016         r = vhost_virtqueue_start(hdev,
1017                                   vdev,
1018                                   hdev->vqs + i,
1019                                   hdev->vq_index + i);
1020         if (r < 0) {
1021             goto fail_vq;
1022         }
1023     }
1024
1025     if (hdev->log_enabled) {
1026         hdev->log_size = vhost_get_log_size(hdev);
1027         hdev->log = hdev->log_size ?
1028             g_malloc0(hdev->log_size * sizeof *hdev->log) : NULL;
1029         r = ioctl(hdev->control, VHOST_SET_LOG_BASE,
1030                   (uint64_t)(unsigned long)hdev->log);
1031         if (r < 0) {
1032             r = -errno;
1033             goto fail_log;
1034         }
1035     }
1036
1037     return 0;
1038 fail_log:
1039 fail_vq:
1040     while (--i >= 0) {
1041         vhost_virtqueue_stop(hdev,
1042                              vdev,
1043                              hdev->vqs + i,
1044                              hdev->vq_index + i);
1045     }
1046     i = hdev->nvqs;
1047 fail_mem:
1048 fail_features:
1049
1050     hdev->started = false;
1051     return r;
1052 }
1053
1054 /* Host notifiers must be enabled at this point. */
1055 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
1056 {
1057     int i;
1058
1059     for (i = 0; i < hdev->nvqs; ++i) {
1060         vhost_virtqueue_stop(hdev,
1061                              vdev,
1062                              hdev->vqs + i,
1063                              hdev->vq_index + i);
1064     }
1065     vhost_log_sync_range(hdev, 0, ~0x0ull);
1066
1067     hdev->started = false;
1068     g_free(hdev->log);
1069     hdev->log = NULL;
1070     hdev->log_size = 0;
1071 }
1072