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 /* enabled until disconnected backend stabilizes */ 31 #define _VHOST_DEBUG 1 32 33 #ifdef _VHOST_DEBUG 34 #define VHOST_OPS_DEBUG(fmt, ...) \ 35 do { error_report(fmt ": %s (%d)", ## __VA_ARGS__, \ 36 strerror(errno), errno); } while (0) 37 #else 38 #define VHOST_OPS_DEBUG(fmt, ...) \ 39 do { } while (0) 40 #endif 41 42 static struct vhost_log *vhost_log; 43 static struct vhost_log *vhost_log_shm; 44 45 static unsigned int used_memslots; 46 static QLIST_HEAD(, vhost_dev) vhost_devices = 47 QLIST_HEAD_INITIALIZER(vhost_devices); 48 49 bool vhost_has_free_slot(void) 50 { 51 unsigned int slots_limit = ~0U; 52 struct vhost_dev *hdev; 53 54 QLIST_FOREACH(hdev, &vhost_devices, entry) { 55 unsigned int r = hdev->vhost_ops->vhost_backend_memslots_limit(hdev); 56 slots_limit = MIN(slots_limit, r); 57 } 58 return slots_limit > used_memslots; 59 } 60 61 static void vhost_dev_sync_region(struct vhost_dev *dev, 62 MemoryRegionSection *section, 63 uint64_t mfirst, uint64_t mlast, 64 uint64_t rfirst, uint64_t rlast) 65 { 66 vhost_log_chunk_t *log = dev->log->log; 67 68 uint64_t start = MAX(mfirst, rfirst); 69 uint64_t end = MIN(mlast, rlast); 70 vhost_log_chunk_t *from = log + start / VHOST_LOG_CHUNK; 71 vhost_log_chunk_t *to = log + end / VHOST_LOG_CHUNK + 1; 72 uint64_t addr = (start / VHOST_LOG_CHUNK) * VHOST_LOG_CHUNK; 73 74 if (end < start) { 75 return; 76 } 77 assert(end / VHOST_LOG_CHUNK < dev->log_size); 78 assert(start / VHOST_LOG_CHUNK < dev->log_size); 79 80 for (;from < to; ++from) { 81 vhost_log_chunk_t log; 82 /* We first check with non-atomic: much cheaper, 83 * and we expect non-dirty to be the common case. */ 84 if (!*from) { 85 addr += VHOST_LOG_CHUNK; 86 continue; 87 } 88 /* Data must be read atomically. We don't really need barrier semantics 89 * but it's easier to use atomic_* than roll our own. */ 90 log = atomic_xchg(from, 0); 91 while (log) { 92 int bit = ctzl(log); 93 hwaddr page_addr; 94 hwaddr section_offset; 95 hwaddr mr_offset; 96 page_addr = addr + bit * VHOST_LOG_PAGE; 97 section_offset = page_addr - section->offset_within_address_space; 98 mr_offset = section_offset + section->offset_within_region; 99 memory_region_set_dirty(section->mr, mr_offset, VHOST_LOG_PAGE); 100 log &= ~(0x1ull << bit); 101 } 102 addr += VHOST_LOG_CHUNK; 103 } 104 } 105 106 static int vhost_sync_dirty_bitmap(struct vhost_dev *dev, 107 MemoryRegionSection *section, 108 hwaddr first, 109 hwaddr last) 110 { 111 int i; 112 hwaddr start_addr; 113 hwaddr end_addr; 114 115 if (!dev->log_enabled || !dev->started) { 116 return 0; 117 } 118 start_addr = section->offset_within_address_space; 119 end_addr = range_get_last(start_addr, int128_get64(section->size)); 120 start_addr = MAX(first, start_addr); 121 end_addr = MIN(last, end_addr); 122 123 for (i = 0; i < dev->mem->nregions; ++i) { 124 struct vhost_memory_region *reg = dev->mem->regions + i; 125 vhost_dev_sync_region(dev, section, start_addr, end_addr, 126 reg->guest_phys_addr, 127 range_get_last(reg->guest_phys_addr, 128 reg->memory_size)); 129 } 130 for (i = 0; i < dev->nvqs; ++i) { 131 struct vhost_virtqueue *vq = dev->vqs + i; 132 vhost_dev_sync_region(dev, section, start_addr, end_addr, vq->used_phys, 133 range_get_last(vq->used_phys, vq->used_size)); 134 } 135 return 0; 136 } 137 138 static void vhost_log_sync(MemoryListener *listener, 139 MemoryRegionSection *section) 140 { 141 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 142 memory_listener); 143 vhost_sync_dirty_bitmap(dev, section, 0x0, ~0x0ULL); 144 } 145 146 static void vhost_log_sync_range(struct vhost_dev *dev, 147 hwaddr first, hwaddr last) 148 { 149 int i; 150 /* FIXME: this is N^2 in number of sections */ 151 for (i = 0; i < dev->n_mem_sections; ++i) { 152 MemoryRegionSection *section = &dev->mem_sections[i]; 153 vhost_sync_dirty_bitmap(dev, section, first, last); 154 } 155 } 156 157 /* Assign/unassign. Keep an unsorted array of non-overlapping 158 * memory regions in dev->mem. */ 159 static void vhost_dev_unassign_memory(struct vhost_dev *dev, 160 uint64_t start_addr, 161 uint64_t size) 162 { 163 int from, to, n = dev->mem->nregions; 164 /* Track overlapping/split regions for sanity checking. */ 165 int overlap_start = 0, overlap_end = 0, overlap_middle = 0, split = 0; 166 167 for (from = 0, to = 0; from < n; ++from, ++to) { 168 struct vhost_memory_region *reg = dev->mem->regions + to; 169 uint64_t reglast; 170 uint64_t memlast; 171 uint64_t change; 172 173 /* clone old region */ 174 if (to != from) { 175 memcpy(reg, dev->mem->regions + from, sizeof *reg); 176 } 177 178 /* No overlap is simple */ 179 if (!ranges_overlap(reg->guest_phys_addr, reg->memory_size, 180 start_addr, size)) { 181 continue; 182 } 183 184 /* Split only happens if supplied region 185 * is in the middle of an existing one. Thus it can not 186 * overlap with any other existing region. */ 187 assert(!split); 188 189 reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); 190 memlast = range_get_last(start_addr, size); 191 192 /* Remove whole region */ 193 if (start_addr <= reg->guest_phys_addr && memlast >= reglast) { 194 --dev->mem->nregions; 195 --to; 196 ++overlap_middle; 197 continue; 198 } 199 200 /* Shrink region */ 201 if (memlast >= reglast) { 202 reg->memory_size = start_addr - reg->guest_phys_addr; 203 assert(reg->memory_size); 204 assert(!overlap_end); 205 ++overlap_end; 206 continue; 207 } 208 209 /* Shift region */ 210 if (start_addr <= reg->guest_phys_addr) { 211 change = memlast + 1 - reg->guest_phys_addr; 212 reg->memory_size -= change; 213 reg->guest_phys_addr += change; 214 reg->userspace_addr += change; 215 assert(reg->memory_size); 216 assert(!overlap_start); 217 ++overlap_start; 218 continue; 219 } 220 221 /* This only happens if supplied region 222 * is in the middle of an existing one. Thus it can not 223 * overlap with any other existing region. */ 224 assert(!overlap_start); 225 assert(!overlap_end); 226 assert(!overlap_middle); 227 /* Split region: shrink first part, shift second part. */ 228 memcpy(dev->mem->regions + n, reg, sizeof *reg); 229 reg->memory_size = start_addr - reg->guest_phys_addr; 230 assert(reg->memory_size); 231 change = memlast + 1 - reg->guest_phys_addr; 232 reg = dev->mem->regions + n; 233 reg->memory_size -= change; 234 assert(reg->memory_size); 235 reg->guest_phys_addr += change; 236 reg->userspace_addr += change; 237 /* Never add more than 1 region */ 238 assert(dev->mem->nregions == n); 239 ++dev->mem->nregions; 240 ++split; 241 } 242 } 243 244 /* Called after unassign, so no regions overlap the given range. */ 245 static void vhost_dev_assign_memory(struct vhost_dev *dev, 246 uint64_t start_addr, 247 uint64_t size, 248 uint64_t uaddr) 249 { 250 int from, to; 251 struct vhost_memory_region *merged = NULL; 252 for (from = 0, to = 0; from < dev->mem->nregions; ++from, ++to) { 253 struct vhost_memory_region *reg = dev->mem->regions + to; 254 uint64_t prlast, urlast; 255 uint64_t pmlast, umlast; 256 uint64_t s, e, u; 257 258 /* clone old region */ 259 if (to != from) { 260 memcpy(reg, dev->mem->regions + from, sizeof *reg); 261 } 262 prlast = range_get_last(reg->guest_phys_addr, reg->memory_size); 263 pmlast = range_get_last(start_addr, size); 264 urlast = range_get_last(reg->userspace_addr, reg->memory_size); 265 umlast = range_get_last(uaddr, size); 266 267 /* check for overlapping regions: should never happen. */ 268 assert(prlast < start_addr || pmlast < reg->guest_phys_addr); 269 /* Not an adjacent or overlapping region - do not merge. */ 270 if ((prlast + 1 != start_addr || urlast + 1 != uaddr) && 271 (pmlast + 1 != reg->guest_phys_addr || 272 umlast + 1 != reg->userspace_addr)) { 273 continue; 274 } 275 276 if (dev->vhost_ops->vhost_backend_can_merge && 277 !dev->vhost_ops->vhost_backend_can_merge(dev, uaddr, size, 278 reg->userspace_addr, 279 reg->memory_size)) { 280 continue; 281 } 282 283 if (merged) { 284 --to; 285 assert(to >= 0); 286 } else { 287 merged = reg; 288 } 289 u = MIN(uaddr, reg->userspace_addr); 290 s = MIN(start_addr, reg->guest_phys_addr); 291 e = MAX(pmlast, prlast); 292 uaddr = merged->userspace_addr = u; 293 start_addr = merged->guest_phys_addr = s; 294 size = merged->memory_size = e - s + 1; 295 assert(merged->memory_size); 296 } 297 298 if (!merged) { 299 struct vhost_memory_region *reg = dev->mem->regions + to; 300 memset(reg, 0, sizeof *reg); 301 reg->memory_size = size; 302 assert(reg->memory_size); 303 reg->guest_phys_addr = start_addr; 304 reg->userspace_addr = uaddr; 305 ++to; 306 } 307 assert(to <= dev->mem->nregions + 1); 308 dev->mem->nregions = to; 309 } 310 311 static uint64_t vhost_get_log_size(struct vhost_dev *dev) 312 { 313 uint64_t log_size = 0; 314 int i; 315 for (i = 0; i < dev->mem->nregions; ++i) { 316 struct vhost_memory_region *reg = dev->mem->regions + i; 317 uint64_t last = range_get_last(reg->guest_phys_addr, 318 reg->memory_size); 319 log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); 320 } 321 for (i = 0; i < dev->nvqs; ++i) { 322 struct vhost_virtqueue *vq = dev->vqs + i; 323 uint64_t last = vq->used_phys + vq->used_size - 1; 324 log_size = MAX(log_size, last / VHOST_LOG_CHUNK + 1); 325 } 326 return log_size; 327 } 328 329 static struct vhost_log *vhost_log_alloc(uint64_t size, bool share) 330 { 331 struct vhost_log *log; 332 uint64_t logsize = size * sizeof(*(log->log)); 333 int fd = -1; 334 335 log = g_new0(struct vhost_log, 1); 336 if (share) { 337 log->log = qemu_memfd_alloc("vhost-log", logsize, 338 F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL, 339 &fd); 340 memset(log->log, 0, logsize); 341 } else { 342 log->log = g_malloc0(logsize); 343 } 344 345 log->size = size; 346 log->refcnt = 1; 347 log->fd = fd; 348 349 return log; 350 } 351 352 static struct vhost_log *vhost_log_get(uint64_t size, bool share) 353 { 354 struct vhost_log *log = share ? vhost_log_shm : vhost_log; 355 356 if (!log || log->size != size) { 357 log = vhost_log_alloc(size, share); 358 if (share) { 359 vhost_log_shm = log; 360 } else { 361 vhost_log = log; 362 } 363 } else { 364 ++log->refcnt; 365 } 366 367 return log; 368 } 369 370 static void vhost_log_put(struct vhost_dev *dev, bool sync) 371 { 372 struct vhost_log *log = dev->log; 373 374 if (!log) { 375 return; 376 } 377 dev->log = NULL; 378 dev->log_size = 0; 379 380 --log->refcnt; 381 if (log->refcnt == 0) { 382 /* Sync only the range covered by the old log */ 383 if (dev->log_size && sync) { 384 vhost_log_sync_range(dev, 0, dev->log_size * VHOST_LOG_CHUNK - 1); 385 } 386 387 if (vhost_log == log) { 388 g_free(log->log); 389 vhost_log = NULL; 390 } else if (vhost_log_shm == log) { 391 qemu_memfd_free(log->log, log->size * sizeof(*(log->log)), 392 log->fd); 393 vhost_log_shm = NULL; 394 } 395 396 g_free(log); 397 } 398 } 399 400 static bool vhost_dev_log_is_shared(struct vhost_dev *dev) 401 { 402 return dev->vhost_ops->vhost_requires_shm_log && 403 dev->vhost_ops->vhost_requires_shm_log(dev); 404 } 405 406 static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size) 407 { 408 struct vhost_log *log = vhost_log_get(size, vhost_dev_log_is_shared(dev)); 409 uint64_t log_base = (uintptr_t)log->log; 410 int r; 411 412 /* inform backend of log switching, this must be done before 413 releasing the current log, to ensure no logging is lost */ 414 r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log); 415 if (r < 0) { 416 VHOST_OPS_DEBUG("vhost_set_log_base failed"); 417 } 418 419 vhost_log_put(dev, true); 420 dev->log = log; 421 dev->log_size = size; 422 } 423 424 static int vhost_verify_ring_mappings(struct vhost_dev *dev, 425 uint64_t start_addr, 426 uint64_t size) 427 { 428 int i; 429 int r = 0; 430 431 for (i = 0; !r && i < dev->nvqs; ++i) { 432 struct vhost_virtqueue *vq = dev->vqs + i; 433 hwaddr l; 434 void *p; 435 436 if (!ranges_overlap(start_addr, size, vq->ring_phys, vq->ring_size)) { 437 continue; 438 } 439 l = vq->ring_size; 440 p = cpu_physical_memory_map(vq->ring_phys, &l, 1); 441 if (!p || l != vq->ring_size) { 442 fprintf(stderr, "Unable to map ring buffer for ring %d\n", i); 443 r = -ENOMEM; 444 } 445 if (p != vq->ring) { 446 fprintf(stderr, "Ring buffer relocated for ring %d\n", i); 447 r = -EBUSY; 448 } 449 cpu_physical_memory_unmap(p, l, 0, 0); 450 } 451 return r; 452 } 453 454 static struct vhost_memory_region *vhost_dev_find_reg(struct vhost_dev *dev, 455 uint64_t start_addr, 456 uint64_t size) 457 { 458 int i, n = dev->mem->nregions; 459 for (i = 0; i < n; ++i) { 460 struct vhost_memory_region *reg = dev->mem->regions + i; 461 if (ranges_overlap(reg->guest_phys_addr, reg->memory_size, 462 start_addr, size)) { 463 return reg; 464 } 465 } 466 return NULL; 467 } 468 469 static bool vhost_dev_cmp_memory(struct vhost_dev *dev, 470 uint64_t start_addr, 471 uint64_t size, 472 uint64_t uaddr) 473 { 474 struct vhost_memory_region *reg = vhost_dev_find_reg(dev, start_addr, size); 475 uint64_t reglast; 476 uint64_t memlast; 477 478 if (!reg) { 479 return true; 480 } 481 482 reglast = range_get_last(reg->guest_phys_addr, reg->memory_size); 483 memlast = range_get_last(start_addr, size); 484 485 /* Need to extend region? */ 486 if (start_addr < reg->guest_phys_addr || memlast > reglast) { 487 return true; 488 } 489 /* userspace_addr changed? */ 490 return uaddr != reg->userspace_addr + start_addr - reg->guest_phys_addr; 491 } 492 493 static void vhost_set_memory(MemoryListener *listener, 494 MemoryRegionSection *section, 495 bool add) 496 { 497 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 498 memory_listener); 499 hwaddr start_addr = section->offset_within_address_space; 500 ram_addr_t size = int128_get64(section->size); 501 bool log_dirty = 502 memory_region_get_dirty_log_mask(section->mr) & ~(1 << DIRTY_MEMORY_MIGRATION); 503 int s = offsetof(struct vhost_memory, regions) + 504 (dev->mem->nregions + 1) * sizeof dev->mem->regions[0]; 505 void *ram; 506 507 dev->mem = g_realloc(dev->mem, s); 508 509 if (log_dirty) { 510 add = false; 511 } 512 513 assert(size); 514 515 /* Optimize no-change case. At least cirrus_vga does this a lot at this time. */ 516 ram = memory_region_get_ram_ptr(section->mr) + section->offset_within_region; 517 if (add) { 518 if (!vhost_dev_cmp_memory(dev, start_addr, size, (uintptr_t)ram)) { 519 /* Region exists with same address. Nothing to do. */ 520 return; 521 } 522 } else { 523 if (!vhost_dev_find_reg(dev, start_addr, size)) { 524 /* Removing region that we don't access. Nothing to do. */ 525 return; 526 } 527 } 528 529 vhost_dev_unassign_memory(dev, start_addr, size); 530 if (add) { 531 /* Add given mapping, merging adjacent regions if any */ 532 vhost_dev_assign_memory(dev, start_addr, size, (uintptr_t)ram); 533 } else { 534 /* Remove old mapping for this memory, if any. */ 535 vhost_dev_unassign_memory(dev, start_addr, size); 536 } 537 dev->mem_changed_start_addr = MIN(dev->mem_changed_start_addr, start_addr); 538 dev->mem_changed_end_addr = MAX(dev->mem_changed_end_addr, start_addr + size - 1); 539 dev->memory_changed = true; 540 used_memslots = dev->mem->nregions; 541 } 542 543 static bool vhost_section(MemoryRegionSection *section) 544 { 545 return memory_region_is_ram(section->mr); 546 } 547 548 static void vhost_begin(MemoryListener *listener) 549 { 550 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 551 memory_listener); 552 dev->mem_changed_end_addr = 0; 553 dev->mem_changed_start_addr = -1; 554 } 555 556 static void vhost_commit(MemoryListener *listener) 557 { 558 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 559 memory_listener); 560 hwaddr start_addr = 0; 561 ram_addr_t size = 0; 562 uint64_t log_size; 563 int r; 564 565 if (!dev->memory_changed) { 566 return; 567 } 568 if (!dev->started) { 569 return; 570 } 571 if (dev->mem_changed_start_addr > dev->mem_changed_end_addr) { 572 return; 573 } 574 575 if (dev->started) { 576 start_addr = dev->mem_changed_start_addr; 577 size = dev->mem_changed_end_addr - dev->mem_changed_start_addr + 1; 578 579 r = vhost_verify_ring_mappings(dev, start_addr, size); 580 assert(r >= 0); 581 } 582 583 if (!dev->log_enabled) { 584 r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); 585 if (r < 0) { 586 VHOST_OPS_DEBUG("vhost_set_mem_table failed"); 587 } 588 dev->memory_changed = false; 589 return; 590 } 591 log_size = vhost_get_log_size(dev); 592 /* We allocate an extra 4K bytes to log, 593 * to reduce the * number of reallocations. */ 594 #define VHOST_LOG_BUFFER (0x1000 / sizeof *dev->log) 595 /* To log more, must increase log size before table update. */ 596 if (dev->log_size < log_size) { 597 vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER); 598 } 599 r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem); 600 if (r < 0) { 601 VHOST_OPS_DEBUG("vhost_set_mem_table failed"); 602 } 603 /* To log less, can only decrease log size after table update. */ 604 if (dev->log_size > log_size + VHOST_LOG_BUFFER) { 605 vhost_dev_log_resize(dev, log_size); 606 } 607 dev->memory_changed = false; 608 } 609 610 static void vhost_region_add(MemoryListener *listener, 611 MemoryRegionSection *section) 612 { 613 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 614 memory_listener); 615 616 if (!vhost_section(section)) { 617 return; 618 } 619 620 ++dev->n_mem_sections; 621 dev->mem_sections = g_renew(MemoryRegionSection, dev->mem_sections, 622 dev->n_mem_sections); 623 dev->mem_sections[dev->n_mem_sections - 1] = *section; 624 memory_region_ref(section->mr); 625 vhost_set_memory(listener, section, true); 626 } 627 628 static void vhost_region_del(MemoryListener *listener, 629 MemoryRegionSection *section) 630 { 631 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 632 memory_listener); 633 int i; 634 635 if (!vhost_section(section)) { 636 return; 637 } 638 639 vhost_set_memory(listener, section, false); 640 memory_region_unref(section->mr); 641 for (i = 0; i < dev->n_mem_sections; ++i) { 642 if (dev->mem_sections[i].offset_within_address_space 643 == section->offset_within_address_space) { 644 --dev->n_mem_sections; 645 memmove(&dev->mem_sections[i], &dev->mem_sections[i+1], 646 (dev->n_mem_sections - i) * sizeof(*dev->mem_sections)); 647 break; 648 } 649 } 650 } 651 652 static void vhost_region_nop(MemoryListener *listener, 653 MemoryRegionSection *section) 654 { 655 } 656 657 static int vhost_virtqueue_set_addr(struct vhost_dev *dev, 658 struct vhost_virtqueue *vq, 659 unsigned idx, bool enable_log) 660 { 661 struct vhost_vring_addr addr = { 662 .index = idx, 663 .desc_user_addr = (uint64_t)(unsigned long)vq->desc, 664 .avail_user_addr = (uint64_t)(unsigned long)vq->avail, 665 .used_user_addr = (uint64_t)(unsigned long)vq->used, 666 .log_guest_addr = vq->used_phys, 667 .flags = enable_log ? (1 << VHOST_VRING_F_LOG) : 0, 668 }; 669 int r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr); 670 if (r < 0) { 671 return -errno; 672 } 673 return 0; 674 } 675 676 static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log) 677 { 678 uint64_t features = dev->acked_features; 679 int r; 680 if (enable_log) { 681 features |= 0x1ULL << VHOST_F_LOG_ALL; 682 } 683 r = dev->vhost_ops->vhost_set_features(dev, features); 684 return r < 0 ? -errno : 0; 685 } 686 687 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log) 688 { 689 int r, i, idx; 690 r = vhost_dev_set_features(dev, enable_log); 691 if (r < 0) { 692 goto err_features; 693 } 694 for (i = 0; i < dev->nvqs; ++i) { 695 idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); 696 r = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, 697 enable_log); 698 if (r < 0) { 699 goto err_vq; 700 } 701 } 702 return 0; 703 err_vq: 704 for (; i >= 0; --i) { 705 idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i); 706 vhost_virtqueue_set_addr(dev, dev->vqs + i, idx, 707 dev->log_enabled); 708 } 709 vhost_dev_set_features(dev, dev->log_enabled); 710 err_features: 711 return r; 712 } 713 714 static int vhost_migration_log(MemoryListener *listener, int enable) 715 { 716 struct vhost_dev *dev = container_of(listener, struct vhost_dev, 717 memory_listener); 718 int r; 719 if (!!enable == dev->log_enabled) { 720 return 0; 721 } 722 if (!dev->started) { 723 dev->log_enabled = enable; 724 return 0; 725 } 726 if (!enable) { 727 r = vhost_dev_set_log(dev, false); 728 if (r < 0) { 729 return r; 730 } 731 vhost_log_put(dev, false); 732 } else { 733 vhost_dev_log_resize(dev, vhost_get_log_size(dev)); 734 r = vhost_dev_set_log(dev, true); 735 if (r < 0) { 736 return r; 737 } 738 } 739 dev->log_enabled = enable; 740 return 0; 741 } 742 743 static void vhost_log_global_start(MemoryListener *listener) 744 { 745 int r; 746 747 r = vhost_migration_log(listener, true); 748 if (r < 0) { 749 abort(); 750 } 751 } 752 753 static void vhost_log_global_stop(MemoryListener *listener) 754 { 755 int r; 756 757 r = vhost_migration_log(listener, false); 758 if (r < 0) { 759 abort(); 760 } 761 } 762 763 static void vhost_log_start(MemoryListener *listener, 764 MemoryRegionSection *section, 765 int old, int new) 766 { 767 /* FIXME: implement */ 768 } 769 770 static void vhost_log_stop(MemoryListener *listener, 771 MemoryRegionSection *section, 772 int old, int new) 773 { 774 /* FIXME: implement */ 775 } 776 777 /* The vhost driver natively knows how to handle the vrings of non 778 * cross-endian legacy devices and modern devices. Only legacy devices 779 * exposed to a bi-endian guest may require the vhost driver to use a 780 * specific endianness. 781 */ 782 static inline bool vhost_needs_vring_endian(VirtIODevice *vdev) 783 { 784 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 785 return false; 786 } 787 #ifdef HOST_WORDS_BIGENDIAN 788 return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_LITTLE; 789 #else 790 return vdev->device_endian == VIRTIO_DEVICE_ENDIAN_BIG; 791 #endif 792 } 793 794 static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev, 795 bool is_big_endian, 796 int vhost_vq_index) 797 { 798 struct vhost_vring_state s = { 799 .index = vhost_vq_index, 800 .num = is_big_endian 801 }; 802 803 if (!dev->vhost_ops->vhost_set_vring_endian(dev, &s)) { 804 return 0; 805 } 806 807 if (errno == ENOTTY) { 808 error_report("vhost does not support cross-endian"); 809 return -ENOSYS; 810 } 811 812 return -errno; 813 } 814 815 static int vhost_virtqueue_start(struct vhost_dev *dev, 816 struct VirtIODevice *vdev, 817 struct vhost_virtqueue *vq, 818 unsigned idx) 819 { 820 hwaddr s, l, a; 821 int r; 822 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); 823 struct vhost_vring_file file = { 824 .index = vhost_vq_index 825 }; 826 struct vhost_vring_state state = { 827 .index = vhost_vq_index 828 }; 829 struct VirtQueue *vvq = virtio_get_queue(vdev, idx); 830 831 832 vq->num = state.num = virtio_queue_get_num(vdev, idx); 833 r = dev->vhost_ops->vhost_set_vring_num(dev, &state); 834 if (r) { 835 return -errno; 836 } 837 838 state.num = virtio_queue_get_last_avail_idx(vdev, idx); 839 r = dev->vhost_ops->vhost_set_vring_base(dev, &state); 840 if (r) { 841 return -errno; 842 } 843 844 if (vhost_needs_vring_endian(vdev)) { 845 r = vhost_virtqueue_set_vring_endian_legacy(dev, 846 virtio_is_big_endian(vdev), 847 vhost_vq_index); 848 if (r) { 849 return -errno; 850 } 851 } 852 853 s = l = virtio_queue_get_desc_size(vdev, idx); 854 a = virtio_queue_get_desc_addr(vdev, idx); 855 vq->desc = cpu_physical_memory_map(a, &l, 0); 856 if (!vq->desc || l != s) { 857 r = -ENOMEM; 858 goto fail_alloc_desc; 859 } 860 s = l = virtio_queue_get_avail_size(vdev, idx); 861 a = virtio_queue_get_avail_addr(vdev, idx); 862 vq->avail = cpu_physical_memory_map(a, &l, 0); 863 if (!vq->avail || l != s) { 864 r = -ENOMEM; 865 goto fail_alloc_avail; 866 } 867 vq->used_size = s = l = virtio_queue_get_used_size(vdev, idx); 868 vq->used_phys = a = virtio_queue_get_used_addr(vdev, idx); 869 vq->used = cpu_physical_memory_map(a, &l, 1); 870 if (!vq->used || l != s) { 871 r = -ENOMEM; 872 goto fail_alloc_used; 873 } 874 875 vq->ring_size = s = l = virtio_queue_get_ring_size(vdev, idx); 876 vq->ring_phys = a = virtio_queue_get_ring_addr(vdev, idx); 877 vq->ring = cpu_physical_memory_map(a, &l, 1); 878 if (!vq->ring || l != s) { 879 r = -ENOMEM; 880 goto fail_alloc_ring; 881 } 882 883 r = vhost_virtqueue_set_addr(dev, vq, vhost_vq_index, dev->log_enabled); 884 if (r < 0) { 885 r = -errno; 886 goto fail_alloc; 887 } 888 889 file.fd = event_notifier_get_fd(virtio_queue_get_host_notifier(vvq)); 890 r = dev->vhost_ops->vhost_set_vring_kick(dev, &file); 891 if (r) { 892 r = -errno; 893 goto fail_kick; 894 } 895 896 /* Clear and discard previous events if any. */ 897 event_notifier_test_and_clear(&vq->masked_notifier); 898 899 /* Init vring in unmasked state, unless guest_notifier_mask 900 * will do it later. 901 */ 902 if (!vdev->use_guest_notifier_mask) { 903 /* TODO: check and handle errors. */ 904 vhost_virtqueue_mask(dev, vdev, idx, false); 905 } 906 907 return 0; 908 909 fail_kick: 910 fail_alloc: 911 cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 912 0, 0); 913 fail_alloc_ring: 914 cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 915 0, 0); 916 fail_alloc_used: 917 cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 918 0, 0); 919 fail_alloc_avail: 920 cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 921 0, 0); 922 fail_alloc_desc: 923 return r; 924 } 925 926 static void vhost_virtqueue_stop(struct vhost_dev *dev, 927 struct VirtIODevice *vdev, 928 struct vhost_virtqueue *vq, 929 unsigned idx) 930 { 931 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, idx); 932 struct vhost_vring_state state = { 933 .index = vhost_vq_index, 934 }; 935 int r; 936 937 r = dev->vhost_ops->vhost_get_vring_base(dev, &state); 938 if (r < 0) { 939 fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r); 940 fflush(stderr); 941 } 942 virtio_queue_set_last_avail_idx(vdev, idx, state.num); 943 virtio_queue_invalidate_signalled_used(vdev, idx); 944 945 /* In the cross-endian case, we need to reset the vring endianness to 946 * native as legacy devices expect so by default. 947 */ 948 if (vhost_needs_vring_endian(vdev)) { 949 vhost_virtqueue_set_vring_endian_legacy(dev, 950 !virtio_is_big_endian(vdev), 951 vhost_vq_index); 952 } 953 954 cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 955 0, virtio_queue_get_ring_size(vdev, idx)); 956 cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx), 957 1, virtio_queue_get_used_size(vdev, idx)); 958 cpu_physical_memory_unmap(vq->avail, virtio_queue_get_avail_size(vdev, idx), 959 0, virtio_queue_get_avail_size(vdev, idx)); 960 cpu_physical_memory_unmap(vq->desc, virtio_queue_get_desc_size(vdev, idx), 961 0, virtio_queue_get_desc_size(vdev, idx)); 962 } 963 964 static void vhost_eventfd_add(MemoryListener *listener, 965 MemoryRegionSection *section, 966 bool match_data, uint64_t data, EventNotifier *e) 967 { 968 } 969 970 static void vhost_eventfd_del(MemoryListener *listener, 971 MemoryRegionSection *section, 972 bool match_data, uint64_t data, EventNotifier *e) 973 { 974 } 975 976 static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev, 977 int n, uint32_t timeout) 978 { 979 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n); 980 struct vhost_vring_state state = { 981 .index = vhost_vq_index, 982 .num = timeout, 983 }; 984 int r; 985 986 if (!dev->vhost_ops->vhost_set_vring_busyloop_timeout) { 987 return -EINVAL; 988 } 989 990 r = dev->vhost_ops->vhost_set_vring_busyloop_timeout(dev, &state); 991 if (r) { 992 return r; 993 } 994 995 return 0; 996 } 997 998 static int vhost_virtqueue_init(struct vhost_dev *dev, 999 struct vhost_virtqueue *vq, int n) 1000 { 1001 int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n); 1002 struct vhost_vring_file file = { 1003 .index = vhost_vq_index, 1004 }; 1005 int r = event_notifier_init(&vq->masked_notifier, 0); 1006 if (r < 0) { 1007 return r; 1008 } 1009 1010 file.fd = event_notifier_get_fd(&vq->masked_notifier); 1011 r = dev->vhost_ops->vhost_set_vring_call(dev, &file); 1012 if (r) { 1013 r = -errno; 1014 goto fail_call; 1015 } 1016 return 0; 1017 fail_call: 1018 event_notifier_cleanup(&vq->masked_notifier); 1019 return r; 1020 } 1021 1022 static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq) 1023 { 1024 event_notifier_cleanup(&vq->masked_notifier); 1025 } 1026 1027 int vhost_dev_init(struct vhost_dev *hdev, void *opaque, 1028 VhostBackendType backend_type, uint32_t busyloop_timeout) 1029 { 1030 uint64_t features; 1031 int i, r, n_initialized_vqs = 0; 1032 1033 hdev->migration_blocker = NULL; 1034 1035 r = vhost_set_backend_type(hdev, backend_type); 1036 assert(r >= 0); 1037 1038 r = hdev->vhost_ops->vhost_backend_init(hdev, opaque); 1039 if (r < 0) { 1040 goto fail; 1041 } 1042 1043 if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) { 1044 fprintf(stderr, "vhost backend memory slots limit is less" 1045 " than current number of present memory slots\n"); 1046 r = -1; 1047 goto fail; 1048 } 1049 1050 r = hdev->vhost_ops->vhost_set_owner(hdev); 1051 if (r < 0) { 1052 goto fail; 1053 } 1054 1055 r = hdev->vhost_ops->vhost_get_features(hdev, &features); 1056 if (r < 0) { 1057 goto fail; 1058 } 1059 1060 for (i = 0; i < hdev->nvqs; ++i, ++n_initialized_vqs) { 1061 r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i); 1062 if (r < 0) { 1063 goto fail; 1064 } 1065 } 1066 1067 if (busyloop_timeout) { 1068 for (i = 0; i < hdev->nvqs; ++i) { 1069 r = vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 1070 busyloop_timeout); 1071 if (r < 0) { 1072 goto fail_busyloop; 1073 } 1074 } 1075 } 1076 1077 hdev->features = features; 1078 1079 hdev->memory_listener = (MemoryListener) { 1080 .begin = vhost_begin, 1081 .commit = vhost_commit, 1082 .region_add = vhost_region_add, 1083 .region_del = vhost_region_del, 1084 .region_nop = vhost_region_nop, 1085 .log_start = vhost_log_start, 1086 .log_stop = vhost_log_stop, 1087 .log_sync = vhost_log_sync, 1088 .log_global_start = vhost_log_global_start, 1089 .log_global_stop = vhost_log_global_stop, 1090 .eventfd_add = vhost_eventfd_add, 1091 .eventfd_del = vhost_eventfd_del, 1092 .priority = 10 1093 }; 1094 1095 if (hdev->migration_blocker == NULL) { 1096 if (!(hdev->features & (0x1ULL << VHOST_F_LOG_ALL))) { 1097 error_setg(&hdev->migration_blocker, 1098 "Migration disabled: vhost lacks VHOST_F_LOG_ALL feature."); 1099 } else if (!qemu_memfd_check()) { 1100 error_setg(&hdev->migration_blocker, 1101 "Migration disabled: failed to allocate shared memory"); 1102 } 1103 } 1104 1105 if (hdev->migration_blocker != NULL) { 1106 migrate_add_blocker(hdev->migration_blocker); 1107 } 1108 1109 hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions)); 1110 hdev->n_mem_sections = 0; 1111 hdev->mem_sections = NULL; 1112 hdev->log = NULL; 1113 hdev->log_size = 0; 1114 hdev->log_enabled = false; 1115 hdev->started = false; 1116 hdev->memory_changed = false; 1117 memory_listener_register(&hdev->memory_listener, &address_space_memory); 1118 QLIST_INSERT_HEAD(&vhost_devices, hdev, entry); 1119 return 0; 1120 1121 fail_busyloop: 1122 while (--i >= 0) { 1123 vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0); 1124 } 1125 fail: 1126 hdev->nvqs = n_initialized_vqs; 1127 vhost_dev_cleanup(hdev); 1128 return r; 1129 } 1130 1131 void vhost_dev_cleanup(struct vhost_dev *hdev) 1132 { 1133 int i; 1134 1135 for (i = 0; i < hdev->nvqs; ++i) { 1136 vhost_virtqueue_cleanup(hdev->vqs + i); 1137 } 1138 if (hdev->mem) { 1139 /* those are only safe after successful init */ 1140 memory_listener_unregister(&hdev->memory_listener); 1141 QLIST_REMOVE(hdev, entry); 1142 } 1143 if (hdev->migration_blocker) { 1144 migrate_del_blocker(hdev->migration_blocker); 1145 error_free(hdev->migration_blocker); 1146 } 1147 g_free(hdev->mem); 1148 g_free(hdev->mem_sections); 1149 if (hdev->vhost_ops) { 1150 hdev->vhost_ops->vhost_backend_cleanup(hdev); 1151 } 1152 assert(!hdev->log); 1153 1154 memset(hdev, 0, sizeof(struct vhost_dev)); 1155 } 1156 1157 /* Stop processing guest IO notifications in qemu. 1158 * Start processing them in vhost in kernel. 1159 */ 1160 int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 1161 { 1162 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); 1163 VirtioBusState *vbus = VIRTIO_BUS(qbus); 1164 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus); 1165 int i, r, e; 1166 if (!k->ioeventfd_started) { 1167 fprintf(stderr, "binding does not support host notifiers\n"); 1168 r = -ENOSYS; 1169 goto fail; 1170 } 1171 1172 for (i = 0; i < hdev->nvqs; ++i) { 1173 r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, 1174 true); 1175 if (r < 0) { 1176 fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r); 1177 goto fail_vq; 1178 } 1179 } 1180 1181 return 0; 1182 fail_vq: 1183 while (--i >= 0) { 1184 e = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, 1185 false); 1186 if (e < 0) { 1187 fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r); 1188 fflush(stderr); 1189 } 1190 assert (e >= 0); 1191 } 1192 fail: 1193 return r; 1194 } 1195 1196 /* Stop processing guest IO notifications in vhost. 1197 * Start processing them in qemu. 1198 * This might actually run the qemu handlers right away, 1199 * so virtio in qemu must be completely setup when this is called. 1200 */ 1201 void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev) 1202 { 1203 BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev))); 1204 int i, r; 1205 1206 for (i = 0; i < hdev->nvqs; ++i) { 1207 r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i, 1208 false); 1209 if (r < 0) { 1210 fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r); 1211 fflush(stderr); 1212 } 1213 assert (r >= 0); 1214 } 1215 } 1216 1217 /* Test and clear event pending status. 1218 * Should be called after unmask to avoid losing events. 1219 */ 1220 bool vhost_virtqueue_pending(struct vhost_dev *hdev, int n) 1221 { 1222 struct vhost_virtqueue *vq = hdev->vqs + n - hdev->vq_index; 1223 assert(n >= hdev->vq_index && n < hdev->vq_index + hdev->nvqs); 1224 return event_notifier_test_and_clear(&vq->masked_notifier); 1225 } 1226 1227 /* Mask/unmask events from this vq. */ 1228 void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n, 1229 bool mask) 1230 { 1231 struct VirtQueue *vvq = virtio_get_queue(vdev, n); 1232 int r, index = n - hdev->vq_index; 1233 struct vhost_vring_file file; 1234 1235 if (mask) { 1236 assert(vdev->use_guest_notifier_mask); 1237 file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier); 1238 } else { 1239 file.fd = event_notifier_get_fd(virtio_queue_get_guest_notifier(vvq)); 1240 } 1241 1242 file.index = hdev->vhost_ops->vhost_get_vq_index(hdev, n); 1243 r = hdev->vhost_ops->vhost_set_vring_call(hdev, &file); 1244 if (r < 0) { 1245 VHOST_OPS_DEBUG("vhost_set_vring_call failed"); 1246 } 1247 } 1248 1249 uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits, 1250 uint64_t features) 1251 { 1252 const int *bit = feature_bits; 1253 while (*bit != VHOST_INVALID_FEATURE_BIT) { 1254 uint64_t bit_mask = (1ULL << *bit); 1255 if (!(hdev->features & bit_mask)) { 1256 features &= ~bit_mask; 1257 } 1258 bit++; 1259 } 1260 return features; 1261 } 1262 1263 void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits, 1264 uint64_t features) 1265 { 1266 const int *bit = feature_bits; 1267 while (*bit != VHOST_INVALID_FEATURE_BIT) { 1268 uint64_t bit_mask = (1ULL << *bit); 1269 if (features & bit_mask) { 1270 hdev->acked_features |= bit_mask; 1271 } 1272 bit++; 1273 } 1274 } 1275 1276 /* Host notifiers must be enabled at this point. */ 1277 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev) 1278 { 1279 int i, r; 1280 1281 hdev->started = true; 1282 1283 r = vhost_dev_set_features(hdev, hdev->log_enabled); 1284 if (r < 0) { 1285 goto fail_features; 1286 } 1287 r = hdev->vhost_ops->vhost_set_mem_table(hdev, hdev->mem); 1288 if (r < 0) { 1289 r = -errno; 1290 goto fail_mem; 1291 } 1292 for (i = 0; i < hdev->nvqs; ++i) { 1293 r = vhost_virtqueue_start(hdev, 1294 vdev, 1295 hdev->vqs + i, 1296 hdev->vq_index + i); 1297 if (r < 0) { 1298 goto fail_vq; 1299 } 1300 } 1301 1302 if (hdev->log_enabled) { 1303 uint64_t log_base; 1304 1305 hdev->log_size = vhost_get_log_size(hdev); 1306 hdev->log = vhost_log_get(hdev->log_size, 1307 vhost_dev_log_is_shared(hdev)); 1308 log_base = (uintptr_t)hdev->log->log; 1309 r = hdev->vhost_ops->vhost_set_log_base(hdev, 1310 hdev->log_size ? log_base : 0, 1311 hdev->log); 1312 if (r < 0) { 1313 r = -errno; 1314 goto fail_log; 1315 } 1316 } 1317 1318 return 0; 1319 fail_log: 1320 vhost_log_put(hdev, false); 1321 fail_vq: 1322 while (--i >= 0) { 1323 vhost_virtqueue_stop(hdev, 1324 vdev, 1325 hdev->vqs + i, 1326 hdev->vq_index + i); 1327 } 1328 i = hdev->nvqs; 1329 fail_mem: 1330 fail_features: 1331 1332 hdev->started = false; 1333 return r; 1334 } 1335 1336 /* Host notifiers must be enabled at this point. */ 1337 void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev) 1338 { 1339 int i; 1340 1341 for (i = 0; i < hdev->nvqs; ++i) { 1342 vhost_virtqueue_stop(hdev, 1343 vdev, 1344 hdev->vqs + i, 1345 hdev->vq_index + i); 1346 } 1347 1348 vhost_log_put(hdev, true); 1349 hdev->started = false; 1350 } 1351