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 "qemu/osdep.h" 17 #include "qapi/error.h" 18 #include "hw/virtio/vhost.h" 19 #include "hw/hw.h" 20 #include "qemu/atomic.h" 21 #include "qemu/range.h" 22 #include "qemu/error-report.h" 23 #include "qemu/memfd.h" 24 #include <linux/vhost.h> 25 #include "exec/address-spaces.h" 26 #include "hw/virtio/virtio-bus.h" 27 #include "hw/virtio/virtio-access.h" 28 #include "migration/migration.h" 29 30 static struct vhost_log *vhost_log; 31 static struct vhost_log *vhost_log_shm; 32 33 static unsigned int used_memslots; 34 static QLIST_HEAD(, vhost_dev) vhost_devices = 35 QLIST_HEAD_INITIALIZER(vhost_devices); 36 37 bool vhost_has_free_slot(void) 38 { 39 unsigned int slots_limit = ~0U; 40 struct vhost_dev *hdev; 41 42 QLIST_FOREACH(hdev, &vhost_devices, entry) { 43 unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev); 44 slots_limit = MIN(slots_limit, r); 45 } 46 return slots_limit > used_memslots; 47 } 48 49 static void vhost_dev_sync_region(struct vhost_dev *dev, 50 MemoryRegionSection *section, 51 uint64_t mfirst, uint64_t mlast, 52 uint64_t rfirst, uint64_t rlast) 53 { 54 vhost_log_chunk_t *log = dev->log->log; 55 56 uint64_t start = MAX(mfirst, rfirst); 57 uint64_t end = MIN(mlast, rlast); 58 vhost_log_chunk_t *from = log + start / VHOST_LOG_CHUNK; 59 vhost_log_chunk_t *to = log + end / VHOST_LOG_CHUNK + 1; 60 uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK; 61 62 if (end < start) { 63 return; 64 } 65 assert(end / VHOST_LOG_CHUNK < dev->log_size); 66 assert(start / VHOST_LOG_CHUNK < dev->log_size); 67 68 for (;from < to; ++from) { 69 vhost_log_chunk_t log; 70 /* We first check with non-atomic: much cheaper, 71 * and we expect non-dirty to be the common case. */ 72 if (!*from) { 73 addr += VHOST_LOG_CHUNK; 74 continue; 75 } 76 /* Data must be read atomically. We don't really need barrier semantics 77 * but it's easier to use atomic_* than roll our own. */ 78 log = atomic_xchg(from, 0); 79 while (log) { 80 int bit = ctzl(log); 81 hwaddr page_addr; 82 hwaddr section_offset; 83 hwaddr mr_offset; 84 page_addr = addr + bit * VHOST_LOG_PAGE; 85 section_offset = page_addr - section->offset_within_address_space; 86 mr_offset = section_offset + section->offset_within_region; 87 memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE); 88 log &= ~(0x1ull << bit); 89 } 90 addr += VHOST_LOG_CHUNK; 91 } 92 } 93 94 static int vhost_sync_dirty_bitmap(struct vhost_dev *dev, 95 MemoryRegionSection *section, 96 hwaddr first, 97 hwaddr last) 98 { 99 int i; 100 hwaddr start_addr; 101 hwaddr end_addr; 102 103 if (!dev->log_enabled || !dev->started) { 104 return 0; 105 } 106 start_addr = section->offset_within_address_space; 107 end_addr = range_get_last(start_addr, int128_get64(section->size)); 108 start_addr = MAX(first, start_addr); 109 end_addr = MIN(last, end_addr); 110 111 for (i = 0; i < dev->mem->nregions; ++i) { 112 struct vhost_memory_region *reg = dev->mem->regions + i; 113 vhost_dev_sync_region(dev, section, start_addr, end_addr, 114 reg->guest_phys_addr, 115 range_get_last(reg->guest_phys_addr, 116 reg->memory_size)); 117 } 118 for (i = 0; i < dev->nvqs; ++i) { 119 struct vhost_virtqueue *vq = dev->vqs + i; 120 vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys, 121 range_get_last(vq->used_phys, vq->used_size)); 122 } 123 return 0; 124 } 125 126 static void vhost_log_sync(MemoryListener *listener, 127 MemoryRegionSection *section) 128 { 129 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 130 memory_listener); 131 vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL); 132 } 133 134 static void vhost_log_sync_range(struct vhost_dev *dev, 135 hwaddr first, hwaddr last) 136 { 137 int i; 138 /* FIXME: this is N^2 in number of sections */ 139 for (i = 0; i < dev->n_mem_sections; ++i) { 140 MemoryRegionSection *section = &dev->mem_sections[i]; 141 vhost_sync_dirty_bitmap(dev, section, first, last); 142 } 143 } 144 145 /* Assign/unassign. Keep an unsorted array of non-overlapping 146 * memory regions in dev->mem. */ 147 static void vhost_dev_unassign_memory(struct vhost_dev *dev, 148 uint64_t start_addr, 149 uint64_t size) 150 { 151 int from, to, n = dev->mem->nregions; 152 /* Track overlapping/split regions for sanity checking. */ 153 int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0; 154 155 for (from = 0, to = 0; from < n; ++from, ++to) { 156 struct vhost_memory_region *reg = dev->mem->regions + to; 157 uint64_t reglast; 158 uint64_t memlast; 159 uint64_t change; 160 161 /* clone old region */ 162 if (to != from) { 163 memcpy(reg, dev->mem->regions + from, sizeof *reg); 164 } 165 166 /* No overlap is simple */ 167 if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size, 168 start_addr, size)) { 169 continue; 170 } 171 172 /* Split only happens if supplied region 173 * is in the middle of an existing one. Thus it can not 174 * overlap with any other existing region. */ 175 assert(!split); 176 177 reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); 178 memlast = range_get_last(start_addr, size); 179 180 /* Remove whole region */ 181 if (start_addr <= reg->guest_phys_addr && memlast >= reglast) { 182 --dev->mem->nregions; 183 --to; 184 ++overlap_middle; 185 continue; 186 } 187 188 /* Shrink region */ 189 if (memlast >= reglast) { 190 reg->memory_size = start_addr - reg->guest_phys_addr; 191 assert(reg->memory_size); 192 assert(!overlap_end); 193 ++overlap_end; 194 continue; 195 } 196 197 /* Shift region */ 198 if (start_addr <= reg->guest_phys_addr) { 199 change = memlast + 1 - reg->guest_phys_addr; 200 reg->memory_size -= change; 201 reg->guest_phys_addr += change; 202 reg->userspace_addr += change; 203 assert(reg->memory_size); 204 assert(!overlap_start); 205 ++overlap_start; 206 continue; 207 } 208 209 /* This only happens if supplied region 210 * is in the middle of an existing one. Thus it can not 211 * overlap with any other existing region. */ 212 assert(!overlap_start); 213 assert(!overlap_end); 214 assert(!overlap_middle); 215 /* Split region: shrink first part, shift second part. */ 216 memcpy(dev->mem->regions + n, reg, sizeof *reg); 217 reg->memory_size = start_addr - reg->guest_phys_addr; 218 assert(reg->memory_size); 219 change = memlast + 1 - reg->guest_phys_addr; 220 reg = dev->mem->regions + n; 221 reg->memory_size -= change; 222 assert(reg->memory_size); 223 reg->guest_phys_addr += change; 224 reg->userspace_addr += change; 225 /* Never add more than 1 region */ 226 assert(dev->mem->nregions == n); 227 ++dev->mem->nregions; 228 ++split; 229 } 230 } 231 232 /* Called after unassign, so no regions overlap the given range. */ 233 static void vhost_dev_assign_memory(struct vhost_dev *dev, 234 uint64_t start_addr, 235 uint64_t size, 236 uint64_t uaddr) 237 { 238 int from, to; 239 struct vhost_memory_region *merged = NULL; 240 for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) { 241 struct vhost_memory_region *reg = dev->mem->regions + to; 242 uint64_t prlast, urlast; 243 uint64_t pmlast, umlast; 244 uint64_t s, e, u; 245 246 /* clone old region */ 247 if (to != from) { 248 memcpy(reg, dev->mem->regions + from, sizeof *reg); 249 } 250 prlast = range_get_last(reg->guest_phys_addr, reg->memory_size); 251 pmlast = range_get_last(start_addr, size); 252 urlast = range_get_last(reg->userspace_addr, reg->memory_size); 253 umlast = range_get_last(uaddr, size); 254 255 /* check for overlapping regions: should never happen. */ 256 assert(prlast < start_addr || pmlast < reg->guest_phys_addr); 257 /* Not an adjacent or overlapping region - do not merge. */ 258 if ((prlast + 1 != start_addr || urlast + 1 != uaddr) && 259 (pmlast + 1 != reg->guest_phys_addr || 260 umlast + 1 != reg->userspace_addr)) { 261 continue; 262 } 263 264 if (dev->vhost_ops->vhost_backend_can_merge && 265 !dev->vhost_ops->vhost_backend_can_merge(dev, uaddr, size, 266 reg->userspace_addr, 267 reg->memory_size)) { 268 continue; 269 } 270 271 if (merged) { 272 --to; 273 assert(to >= 0); 274 } else { 275 merged = reg; 276 } 277 u = MIN(uaddr, reg->userspace_addr); 278 s = MIN(start_addr, reg->guest_phys_addr); 279 e = MAX(pmlast, prlast); 280 uaddr = merged->userspace_addr = u; 281 start_addr = merged->guest_phys_addr = s; 282 size = merged->memory_size = e - s + 1; 283 assert(merged->memory_size); 284 } 285 286 if (!merged) { 287 struct vhost_memory_region *reg = dev->mem->regions + to; 288 memset(reg, 0, sizeof *reg); 289 reg->memory_size = size; 290 assert(reg->memory_size); 291 reg->guest_phys_addr = start_addr; 292 reg->userspace_addr = uaddr; 293 ++to; 294 } 295 assert(to <= dev->mem->nregions + 1); 296 dev->mem->nregions = to; 297 } 298 299 static uint64_t vhost_get_log_size(struct vhost_dev *dev) 300 { 301 uint64_t log_size = 0; 302 int i; 303 for (i = 0; i < dev->mem->nregions; ++i) { 304 struct vhost_memory_region *reg = dev->mem->regions + i; 305 uint64_t last = range_get_last(reg->guest_phys_addr, 306 reg->memory_size); 307 log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); 308 } 309 for (i = 0; i < dev->nvqs; ++i) { 310 struct vhost_virtqueue *vq = dev->vqs + i; 311 uint64_t last = vq->used_phys + vq->used_size - 1; 312 log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); 313 } 314 return log_size; 315 } 316 317 static struct vhost_log *vhost_log_alloc(uint64_t size, bool share) 318 { 319 struct vhost_log *log; 320 uint64_t logsize = size * sizeof(*(log->log)); 321 int fd = -1; 322 323 log = g_new0(struct vhost_log, 1); 324 if (share) { 325 log->log = qemu_memfd_alloc("vhost-log", logsize, 326 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL, 327 &fd); 328 memset(log->log, 0, logsize); 329 } else { 330 log->log = g_malloc0(logsize); 331 } 332 333 log->size = size; 334 log->refcnt = 1; 335 log->fd = fd; 336 337 return log; 338 } 339 340 static struct vhost_log *vhost_log_get(uint64_t size, bool share) 341 { 342 struct vhost_log *log = share ? vhost_log_shm : vhost_log; 343 344 if (!log || log->size != size) { 345 log = vhost_log_alloc(size, share); 346 if (share) { 347 vhost_log_shm = log; 348 } else { 349 vhost_log = log; 350 } 351 } else { 352 ++log->refcnt; 353 } 354 355 return log; 356 } 357 358 static void vhost_log_put(struct vhost_dev *dev, bool sync) 359 { 360 struct vhost_log *log = dev->log; 361 362 if (!log) { 363 return; 364 } 365 366 --log->refcnt; 367 if (log->refcnt == 0) { 368 /* Sync only the range covered by the old log */ 369 if (dev->log_size && sync) { 370 vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1); 371 } 372 373 if (vhost_log == log) { 374 g_free(log->log); 375 vhost_log = NULL; 376 } else if (vhost_log_shm == log) { 377 qemu_memfd_free(log->log, log->size * sizeof(*(log->log)), 378 log->fd); 379 vhost_log_shm = NULL; 380 } 381 382 g_free(log); 383 } 384 } 385 386 static bool vhost_dev_log_is_shared(struct vhost_dev *dev) 387 { 388 return dev->vhost_ops->vhost_requires_shm_log && 389 dev->vhost_ops->vhost_requires_shm_log(dev); 390 } 391 392 static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size) 393 { 394 struct vhost_log *log = vhost_log_get(size, vhost_dev_log_is_shared(dev)); 395 uint64_t log_base = (uintptr_t)log->log; 396 int r; 397 398 /* inform backend of log switching, this must be done before 399 releasing the current log, to ensure no logging is lost */ 400 r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log); 401 assert(r >= 0); 402 vhost_log_put(dev, true); 403 dev->log = log; 404 dev->log_size = size; 405 } 406 407 static int vhost_verify_ring_mappings(struct vhost_dev *dev, 408 uint64_t start_addr, 409 uint64_t size) 410 { 411 int i; 412 int r = 0; 413 414 for (i = 0; !r && i < dev->nvqs; ++i) { 415 struct vhost_virtqueue *vq = dev->vqs + i; 416 hwaddr l; 417 void *p; 418 419 if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { 420 continue; 421 } 422 l = vq->ring_size; 423 p = cpu_physical_memory_map(vq->ring_phys, &l, 1); 424 if (!p || l != vq->ring_size) { 425 fprintf(stderr, "Unable to map ring buffer for ring %d\n", i); 426 r = -ENOMEM; 427 } 428 if (p != vq->ring) { 429 fprintf(stderr, "Ring buffer relocated for ring %d\n", i); 430 r = -EBUSY; 431 } 432 cpu_physical_memory_unmap(p, l, 0, 0); 433 } 434 return r; 435 } 436 437 static struct vhost_memory_region *vhost_dev_find_reg(struct vhost_dev *dev, 438 uint64_t start_addr, 439 uint64_t size) 440 { 441 int i, n = dev->mem->nregions; 442 for (i = 0; i < n; ++i) { 443 struct vhost_memory_region *reg = dev->mem->regions + i; 444 if (ranges_overlap(reg->guest_phys_addr, reg->memory_size, 445 start_addr, size)) { 446 return reg; 447 } 448 } 449 return NULL; 450 } 451 452 static bool vhost_dev_cmp_memory(struct vhost_dev *dev, 453 uint64_t start_addr, 454 uint64_t size, 455 uint64_t uaddr) 456 { 457 struct vhost_memory_region *reg = vhost_dev_find_reg(dev, start_addr, size); 458 uint64_t reglast; 459 uint64_t memlast; 460 461 if (!reg) { 462 return true; 463 } 464 465 reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); 466 memlast = range_get_last(start_addr, size); 467 468 /* Need to extend region? */ 469 if (start_addr < reg->guest_phys_addr || memlast > reglast) { 470 return true; 471 } 472 /* userspace_addr changed? */ 473 return uaddr != reg->userspace_addr + start_addr - reg->guest_phys_addr; 474 } 475 476 static void vhost_set_memory(MemoryListener *listener, 477 MemoryRegionSection *section, 478 bool add) 479 { 480 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 481 memory_listener); 482 hwaddr start_addr = section->offset_within_address_space; 483 ram_addr_t size = int128_get64(section->size); 484 bool log_dirty = 485 memory_region_get_dirty_log_mask(section->mr) & ~(1 << DIRTY_MEMORY_MIGRATION); 486 int s = offsetof(struct vhost_memory, regions) + 487 (dev->mem->nregions + 1) * sizeof dev->mem->regions[0]; 488 void *ram; 489 490 dev->mem = g_realloc(dev->mem, s); 491 492 if (log_dirty) { 493 add = false; 494 } 495 496 assert(size); 497 498 /* Optimize no-change case. At least cirrus_vga does this a lot at this time. */ 499 ram = memory_region_get_ram_ptr(section->mr) + section->offset_within_region; 500 if (add) { 501 if (!vhost_dev_cmp_memory(dev, start_addr, size, (uintptr_t)ram)) { 502 /* Region exists with same address. Nothing to do. */ 503 return; 504 } 505 } else { 506 if (!vhost_dev_find_reg(dev, start_addr, size)) { 507 /* Removing region that we don't access. Nothing to do. */ 508 return; 509 } 510 } 511 512 vhost_dev_unassign_memory(dev, start_addr, size); 513 if (add) { 514 /* Add given mapping, merging adjacent regions if any */ 515 vhost_dev_assign_memory(dev, start_addr, size, (uintptr_t)ram); 516 } else { 517 /* Remove old mapping for this memory, if any. */ 518 vhost_dev_unassign_memory(dev, start_addr, size); 519 } 520 dev->mem_changed_start_addr = MIN(dev->mem_changed_start_addr, start_addr); 521 dev->mem_changed_end_addr = MAX(dev->mem_changed_end_addr, start_addr + size - 1); 522 dev->memory_changed = true; 523 used_memslots = dev->mem->nregions; 524 } 525 526 static bool vhost_section(MemoryRegionSection *section) 527 { 528 return memory_region_is_ram(section->mr); 529 } 530 531 static void vhost_begin(MemoryListener *listener) 532 { 533 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 534 memory_listener); 535 dev->mem_changed_end_addr = 0; 536 dev->mem_changed_start_addr = -1; 537 } 538 539 static void vhost_commit(MemoryListener *listener) 540 { 541 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 542 memory_listener); 543 hwaddr start_addr = 0; 544 ram_addr_t size = 0; 545 uint64_t log_size; 546 int r; 547 548 if (!dev->memory_changed) { 549 return; 550 } 551 if (!dev->started) { 552 return; 553 } 554 if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) { 555 return; 556 } 557 558 if (dev->started) { 559 start_addr = dev->mem_changed_start_addr; 560 size = dev->mem_changed_end_addr - dev->mem_changed_start_addr + 1; 561 562 r = vhost_verify_ring_mappings(dev, start_addr, size); 563 assert(r >= 0); 564 } 565 566 if (!dev->log_enabled) { 567 r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); 568 assert(r >= 0); 569 dev->memory_changed = false; 570 return; 571 } 572 log_size = vhost_get_log_size(dev); 573 /* We allocate an extra 4K bytes to log, 574 * to reduce the * number of reallocations. */ 575 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log) 576 /* To log more, must increase log size before table update. */ 577 if (dev->log_size < log_size) { 578 vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER); 579 } 580 r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); 581 assert(r >= 0); 582 /* To log less, can only decrease log size after table update. */ 583 if (dev->log_size > log_size + VHOST_LOG_BUFFER) { 584 vhost_dev_log_resize(dev, log_size); 585 } 586 dev->memory_changed = false; 587 } 588 589 static void vhost_region_add(MemoryListener *listener, 590 MemoryRegionSection *section) 591 { 592 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 593 memory_listener); 594 595 if (!vhost_section(section)) { 596 return; 597 } 598 599 ++dev->n_mem_sections; 600 dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections, 601 dev->n_mem_sections); 602 dev->mem_sections[dev->n_mem_sections - 1] = *section; 603 memory_region_ref(section->mr); 604 vhost_set_memory(listener, section, true); 605 } 606 607 static void vhost_region_del(MemoryListener *listener, 608 MemoryRegionSection *section) 609 { 610 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 611 memory_listener); 612 int i; 613 614 if (!vhost_section(section)) { 615 return; 616 } 617 618 vhost_set_memory(listener, section, false); 619 memory_region_unref(section->mr); 620 for (i = 0; i < dev->n_mem_sections; ++i) { 621 if (dev->mem_sections[i].offset_within_address_space 622 == section->offset_within_address_space) { 623 --dev->n_mem_sections; 624 memmove(&dev->mem_sections[i], &dev->mem_sections[i+1], 625 (dev->n_mem_sections - i) * sizeof(*dev->mem_sections)); 626 break; 627 } 628 } 629 } 630 631 static void vhost_region_nop(MemoryListener *listener, 632 MemoryRegionSection *section) 633 { 634 } 635 636 static int vhost_virtqueue_set_addr(struct vhost_dev *dev, 637 struct vhost_virtqueue *vq, 638 unsigned idx, bool enable_log) 639 { 640 struct vhost_vring_addr addr = { 641 .index = idx, 642 .desc_user_addr = (uint64_t)(unsigned long)vq->desc, 643 .avail_user_addr = (uint64_t)(unsigned long)vq->avail, 644 .used_user_addr = (uint64_t)(unsigned long)vq->used, 645 .log_guest_addr = vq->used_phys, 646 .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0, 647 }; 648 int r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr); 649 if (r < 0) { 650 return -errno; 651 } 652 return 0; 653 } 654 655 static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log) 656 { 657 uint64_t features = dev->acked_features; 658 int r; 659 if (enable_log) { 660 features |= 0x1ULL << VHOST_F_LOG_ALL; 661 } 662 r = dev->vhost_ops->vhost_set_features(dev, features); 663 return r < 0 ? -errno : 0; 664 } 665 666 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) 667 { 668 int r, t, i, idx; 669 r = vhost_dev_set_features(dev, enable_log); 670 if (r < 0) { 671 goto err_features; 672 } 673 for (i = 0; i < dev->nvqs; ++i) { 674 idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); 675 r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, 676 enable_log); 677 if (r < 0) { 678 goto err_vq; 679 } 680 } 681 return 0; 682 err_vq: 683 for (; i >= 0; --i) { 684 idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); 685 t = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, 686 dev->log_enabled); 687 assert(t >= 0); 688 } 689 t = vhost_dev_set_features(dev, dev->log_enabled); 690 assert(t >= 0); 691 err_features: 692 return r; 693 } 694 695 static int vhost_migration_log(MemoryListener *listener, int enable) 696 { 697 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 698 memory_listener); 699 int r; 700 if (!!enable == dev->log_enabled) { 701 return 0; 702 } 703 if (!dev->started) { 704 dev->log_enabled = enable; 705 return 0; 706 } 707 if (!enable) { 708 r = vhost_dev_set_log(dev, false); 709 if (r < 0) { 710 return r; 711 } 712 vhost_log_put(dev, false); 713 dev->log = NULL; 714 dev->log_size = 0; 715 } else { 716 vhost_dev_log_resize(dev, vhost_get_log_size(dev)); 717 r = vhost_dev_set_log(dev, true); 718 if (r < 0) { 719 return r; 720 } 721 } 722 dev->log_enabled = enable; 723 return 0; 724 } 725 726 static void vhost_log_global_start(MemoryListener *listener) 727 { 728 int r; 729 730 r = vhost_migration_log(listener, true); 731 if (r < 0) { 732 abort(); 733 } 734 } 735 736 static void vhost_log_global_stop(MemoryListener *listener) 737 { 738 int r; 739 740 r = vhost_migration_log(listener, false); 741 if (r < 0) { 742 abort(); 743 } 744 } 745 746 static void vhost_log_start(MemoryListener *listener, 747 MemoryRegionSection *section, 748 int old, int new) 749 { 750 /* FIXME: implement */ 751 } 752 753 static void vhost_log_stop(MemoryListener *listener, 754 MemoryRegionSection *section, 755 int old, int new) 756 { 757 /* FIXME: implement */ 758 } 759 760 /* The vhost driver natively knows how to handle the vrings of non 761 * cross-endian legacy devices and modern devices. Only legacy devices 762 * exposed to a bi-endian guest may require the vhost driver to use a 763 * specific endianness. 764 */ 765 static inline bool vhost_needs_vring_endian(VirtIODevice *vdev) 766 { 767 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 768 return false; 769 } 770 #ifdef HOST_WORDS_BIGENDIAN 771 return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_LITTLE; 772 #else 773 return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG; 774 #endif 775 } 776 777 static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev, 778 bool is_big_endian, 779 int vhost_vq_index) 780 { 781 struct vhost_vring_state s = { 782 .index = vhost_vq_index, 783 .num = is_big_endian 784 }; 785 786 if (!dev->vhost_ops->vhost_set_vring_endian(dev, &s)) { 787 return 0; 788 } 789 790 if (errno == ENOTTY) { 791 error_report("vhost does not support cross-endian"); 792 return -ENOSYS; 793 } 794 795 return -errno; 796 } 797 798 static int vhost_virtqueue_start(struct vhost_dev *dev, 799 struct VirtIODevice *vdev, 800 struct vhost_virtqueue *vq, 801 unsigned idx) 802 { 803 hwaddr s, l, a; 804 int r; 805 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); 806 struct vhost_vring_file file = { 807 .index = vhost_vq_index 808 }; 809 struct vhost_vring_state state = { 810 .index = vhost_vq_index 811 }; 812 struct VirtQueue *vvq = virtio_get_queue(vdev, idx); 813 814 815 vq->num = state.num = virtio_queue_get_num(vdev, idx); 816 r = dev->vhost_ops->vhost_set_vring_num(dev, &state); 817 if (r) { 818 return -errno; 819 } 820 821 state.num = virtio_queue_get_last_avail_idx(vdev, idx); 822 r = dev->vhost_ops->vhost_set_vring_base(dev, &state); 823 if (r) { 824 return -errno; 825 } 826 827 if (vhost_needs_vring_endian(vdev)) { 828 r = vhost_virtqueue_set_vring_endian_legacy(dev, 829 virtio_is_big_endian(vdev), 830 vhost_vq_index); 831 if (r) { 832 return -errno; 833 } 834 } 835 836 s = l = virtio_queue_get_desc_size(vdev, idx); 837 a = virtio_queue_get_desc_addr(vdev, idx); 838 vq->desc = cpu_physical_memory_map(a, &l, 0); 839 if (!vq->desc || l != s) { 840 r = -ENOMEM; 841 goto fail_alloc_desc; 842 } 843 s = l = virtio_queue_get_avail_size(vdev, idx); 844 a = virtio_queue_get_avail_addr(vdev, idx); 845 vq->avail = cpu_physical_memory_map(a, &l, 0); 846 if (!vq->avail || l != s) { 847 r = -ENOMEM; 848 goto fail_alloc_avail; 849 } 850 vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx); 851 vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx); 852 vq->used = cpu_physical_memory_map(a, &l, 1); 853 if (!vq->used || l != s) { 854 r = -ENOMEM; 855 goto fail_alloc_used; 856 } 857 858 vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx); 859 vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx); 860 vq->ring = cpu_physical_memory_map(a, &l, 1); 861 if (!vq->ring || l != s) { 862 r = -ENOMEM; 863 goto fail_alloc_ring; 864 } 865 866 r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled); 867 if (r < 0) { 868 r = -errno; 869 goto fail_alloc; 870 } 871 872 file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq)); 873 r = dev->vhost_ops->vhost_set_vring_kick(dev, &file); 874 if (r) { 875 r = -errno; 876 goto fail_kick; 877 } 878 879 /* Clear and discard previous events if any. */ 880 event_notifier_test_and_clear(&vq->masked_notifier); 881 882 /* Init vring in unmasked state, unless guest_notifier_mask 883 * will do it later. 884 */ 885 if (!vdev->use_guest_notifier_mask) { 886 /* TODO: check and handle errors. */ 887 vhost_virtqueue_mask(dev, vdev, idx, false); 888 } 889 890 return 0; 891 892 fail_kick: 893 fail_alloc: 894 cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 895 0, 0); 896 fail_alloc_ring: 897 cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 898 0, 0); 899 fail_alloc_used: 900 cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 901 0, 0); 902 fail_alloc_avail: 903 cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 904 0, 0); 905 fail_alloc_desc: 906 return r; 907 } 908 909 static void vhost_virtqueue_stop(struct vhost_dev *dev, 910 struct VirtIODevice *vdev, 911 struct vhost_virtqueue *vq, 912 unsigned idx) 913 { 914 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); 915 struct vhost_vring_state state = { 916 .index = vhost_vq_index, 917 }; 918 int r; 919 920 r = dev->vhost_ops->vhost_get_vring_base(dev, &state); 921 if (r < 0) { 922 fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r); 923 fflush(stderr); 924 } 925 virtio_queue_set_last_avail_idx(vdev, idx, state.num); 926 virtio_queue_invalidate_signalled_used(vdev, idx); 927 928 /* In the cross-endian case, we need to reset the vring endianness to 929 * native as legacy devices expect so by default. 930 */ 931 if (vhost_needs_vring_endian(vdev)) { 932 r = vhost_virtqueue_set_vring_endian_legacy(dev, 933 !virtio_is_big_endian(vdev), 934 vhost_vq_index); 935 if (r < 0) { 936 error_report("failed to reset vring endianness"); 937 } 938 } 939 940 assert (r >= 0); 941 cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 942 0, virtio_queue_get_ring_size(vdev, idx)); 943 cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 944 1, virtio_queue_get_used_size(vdev, idx)); 945 cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 946 0, virtio_queue_get_avail_size(vdev, idx)); 947 cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 948 0, virtio_queue_get_desc_size(vdev, idx)); 949 } 950 951 static void vhost_eventfd_add(MemoryListener *listener, 952 MemoryRegionSection *section, 953 bool match_data, uint64_t data, EventNotifier *e) 954 { 955 } 956 957 static void vhost_eventfd_del(MemoryListener *listener, 958 MemoryRegionSection *section, 959 bool match_data, uint64_t data, EventNotifier *e) 960 { 961 } 962 963 static int vhost_virtqueue_init(struct vhost_dev *dev, 964 struct vhost_virtqueue *vq, int n) 965 { 966 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n); 967 struct vhost_vring_file file = { 968 .index = vhost_vq_index, 969 }; 970 int r = event_notifier_init(&vq->masked_notifier, 0); 971 if (r < 0) { 972 return r; 973 } 974 975 file.fd = event_notifier_get_fd(&vq->masked_notifier); 976 r = dev->vhost_ops->vhost_set_vring_call(dev, &file); 977 if (r) { 978 r = -errno; 979 goto fail_call; 980 } 981 return 0; 982 fail_call: 983 event_notifier_cleanup(&vq->masked_notifier); 984 return r; 985 } 986 987 static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq) 988 { 989 event_notifier_cleanup(&vq->masked_notifier); 990 } 991 992 int vhost_dev_init(struct vhost_dev *hdev, void *opaque, 993 VhostBackendType backend_type) 994 { 995 uint64_t features; 996 int i, r; 997 998 hdev->migration_blocker = NULL; 999 1000 if (vhost_set_backend_type(hdev, backend_type) < 0) { 1001 close((uintptr_t)opaque); 1002 return -1; 1003 } 1004 1005 if (hdev->vhost_ops->vhost_backend_init(hdev, opaque) < 0) { 1006 close((uintptr_t)opaque); 1007 return -errno; 1008 } 1009 1010 if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { 1011 fprintf(stderr, "vhost backend memory slots limit is less" 1012 " than current number of present memory slots\n"); 1013 close((uintptr_t)opaque); 1014 return -1; 1015 } 1016 QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); 1017 1018 r = hdev->vhost_ops->vhost_set_owner(hdev); 1019 if (r < 0) { 1020 goto fail; 1021 } 1022 1023 r = hdev->vhost_ops->vhost_get_features(hdev, &features); 1024 if (r < 0) { 1025 goto fail; 1026 } 1027 1028 for (i = 0; i < hdev->nvqs; ++i) { 1029 r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i); 1030 if (r < 0) { 1031 goto fail_vq; 1032 } 1033 } 1034 hdev->features = features; 1035 1036 hdev->memory_listener = (MemoryListener) { 1037 .begin = vhost_begin, 1038 .commit = vhost_commit, 1039 .region_add = vhost_region_add, 1040 .region_del = vhost_region_del, 1041 .region_nop = vhost_region_nop, 1042 .log_start = vhost_log_start, 1043 .log_stop = vhost_log_stop, 1044 .log_sync = vhost_log_sync, 1045 .log_global_start = vhost_log_global_start, 1046 .log_global_stop = vhost_log_global_stop, 1047 .eventfd_add = vhost_eventfd_add, 1048 .eventfd_del = vhost_eventfd_del, 1049 .priority = 10 1050 }; 1051 1052 if (hdev->migration_blocker == NULL) { 1053 if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) { 1054 error_setg(&hdev->migration_blocker, 1055 "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature."); 1056 } else if (!qemu_memfd_check()) { 1057 error_setg(&hdev->migration_blocker, 1058 "Migration disabled: failed to allocate shared memory"); 1059 } 1060 } 1061 1062 if (hdev->migration_blocker != NULL) { 1063 migrate_add_blocker(hdev->migration_blocker); 1064 } 1065 1066 hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions)); 1067 hdev->n_mem_sections = 0; 1068 hdev->mem_sections = NULL; 1069 hdev->log = NULL; 1070 hdev->log_size = 0; 1071 hdev->log_enabled = false; 1072 hdev->started = false; 1073 hdev->memory_changed = false; 1074 memory_listener_register(&hdev->memory_listener, &address_space_memory); 1075 return 0; 1076 fail_vq: 1077 while (--i >= 0) { 1078 vhost_virtqueue_cleanup(hdev->vqs + i); 1079 } 1080 fail: 1081 r = -errno; 1082 hdev->vhost_ops->vhost_backend_cleanup(hdev); 1083 QLIST_REMOVE(hdev, entry); 1084 return r; 1085 } 1086 1087 void vhost_dev_cleanup(struct vhost_dev *hdev) 1088 { 1089 int i; 1090 for (i = 0; i < hdev->nvqs; ++i) { 1091 vhost_virtqueue_cleanup(hdev->vqs + i); 1092 } 1093 memory_listener_unregister(&hdev->memory_listener); 1094 if (hdev->migration_blocker) { 1095 migrate_del_blocker(hdev->migration_blocker); 1096 error_free(hdev->migration_blocker); 1097 } 1098 g_free(hdev->mem); 1099 g_free(hdev->mem_sections); 1100 hdev->vhost_ops->vhost_backend_cleanup(hdev); 1101 QLIST_REMOVE(hdev, entry); 1102 } 1103 1104 /* Stop processing guest IO notifications in qemu. 1105 * Start processing them in vhost in kernel. 1106 */ 1107 int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 1108 { 1109 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); 1110 VirtioBusState *vbus = VIRTIO_BUS(qbus); 1111 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); 1112 int i, r, e; 1113 if (!k->set_host_notifier) { 1114 fprintf(stderr, "binding does not support host notifiers\n"); 1115 r = -ENOSYS; 1116 goto fail; 1117 } 1118 1119 for (i = 0; i < hdev->nvqs; ++i) { 1120 r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, true); 1121 if (r < 0) { 1122 fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r); 1123 goto fail_vq; 1124 } 1125 } 1126 1127 return 0; 1128 fail_vq: 1129 while (--i >= 0) { 1130 e = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false); 1131 if (e < 0) { 1132 fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r); 1133 fflush(stderr); 1134 } 1135 assert (e >= 0); 1136 } 1137 fail: 1138 return r; 1139 } 1140 1141 /* Stop processing guest IO notifications in vhost. 1142 * Start processing them in qemu. 1143 * This might actually run the qemu handlers right away, 1144 * so virtio in qemu must be completely setup when this is called. 1145 */ 1146 void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 1147 { 1148 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); 1149 VirtioBusState *vbus = VIRTIO_BUS(qbus); 1150 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); 1151 int i, r; 1152 1153 for (i = 0; i < hdev->nvqs; ++i) { 1154 r = k->set_host_notifier(qbus->parent, hdev->vq_index + i, false); 1155 if (r < 0) { 1156 fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r); 1157 fflush(stderr); 1158 } 1159 assert (r >= 0); 1160 } 1161 } 1162 1163 /* Test and clear event pending status. 1164 * Should be called after unmask to avoid losing events. 1165 */ 1166 bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n) 1167 { 1168 struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index; 1169 assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs); 1170 return event_notifier_test_and_clear(&vq->masked_notifier); 1171 } 1172 1173 /* Mask/unmask events from this vq. */ 1174 void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, 1175 bool mask) 1176 { 1177 struct VirtQueue *vvq = virtio_get_queue(vdev, n); 1178 int r, index = n - hdev->vq_index; 1179 struct vhost_vring_file file; 1180 1181 if (mask) { 1182 assert(vdev->use_guest_notifier_mask); 1183 file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier); 1184 } else { 1185 file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq)); 1186 } 1187 1188 file.index = hdev->vhost_ops->vhost_get_vq_index(hdev, n); 1189 r = hdev->vhost_ops->vhost_set_vring_call(hdev, &file); 1190 assert(r >= 0); 1191 } 1192 1193 uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits, 1194 uint64_t features) 1195 { 1196 const int *bit = feature_bits; 1197 while (*bit != VHOST_INVALID_FEATURE_BIT) { 1198 uint64_t bit_mask = (1ULL << *bit); 1199 if (!(hdev->features & bit_mask)) { 1200 features &= ~bit_mask; 1201 } 1202 bit++; 1203 } 1204 return features; 1205 } 1206 1207 void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits, 1208 uint64_t features) 1209 { 1210 const int *bit = feature_bits; 1211 while (*bit != VHOST_INVALID_FEATURE_BIT) { 1212 uint64_t bit_mask = (1ULL << *bit); 1213 if (features & bit_mask) { 1214 hdev->acked_features |= bit_mask; 1215 } 1216 bit++; 1217 } 1218 } 1219 1220 /* Host notifiers must be enabled at this point. */ 1221 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) 1222 { 1223 int i, r; 1224 1225 hdev->started = true; 1226 1227 r = vhost_dev_set_features(hdev, hdev->log_enabled); 1228 if (r < 0) { 1229 goto fail_features; 1230 } 1231 r = hdev->vhost_ops->vhost_set_mem_table(hdev, hdev->mem); 1232 if (r < 0) { 1233 r = -errno; 1234 goto fail_mem; 1235 } 1236 for (i = 0; i < hdev->nvqs; ++i) { 1237 r = vhost_virtqueue_start(hdev, 1238 vdev, 1239 hdev->vqs + i, 1240 hdev->vq_index + i); 1241 if (r < 0) { 1242 goto fail_vq; 1243 } 1244 } 1245 1246 if (hdev->log_enabled) { 1247 uint64_t log_base; 1248 1249 hdev->log_size = vhost_get_log_size(hdev); 1250 hdev->log = vhost_log_get(hdev->log_size, 1251 vhost_dev_log_is_shared(hdev)); 1252 log_base = (uintptr_t)hdev->log->log; 1253 r = hdev->vhost_ops->vhost_set_log_base(hdev, 1254 hdev->log_size ? log_base : 0, 1255 hdev->log); 1256 if (r < 0) { 1257 r = -errno; 1258 goto fail_log; 1259 } 1260 } 1261 1262 return 0; 1263 fail_log: 1264 vhost_log_put(hdev, false); 1265 fail_vq: 1266 while (--i >= 0) { 1267 vhost_virtqueue_stop(hdev, 1268 vdev, 1269 hdev->vqs + i, 1270 hdev->vq_index + i); 1271 } 1272 i = hdev->nvqs; 1273 fail_mem: 1274 fail_features: 1275 1276 hdev->started = false; 1277 return r; 1278 } 1279 1280 /* Host notifiers must be enabled at this point. */ 1281 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) 1282 { 1283 int i; 1284 1285 for (i = 0; i < hdev->nvqs; ++i) { 1286 vhost_virtqueue_stop(hdev, 1287 vdev, 1288 hdev->vqs + i, 1289 hdev->vq_index + i); 1290 } 1291 1292 vhost_log_put(hdev, true); 1293 hdev->started = false; 1294 hdev->log = NULL; 1295 hdev->log_size = 0; 1296 } 1297 1298