1 /* 2 * Virtio Support 3 * 4 * Copyright IBM, Corp. 2007 5 * 6 * Authors: 7 * Anthony Liguori <aliguori@us.ibm.com> 8 * 9 * This work is licensed under the terms of the GNU GPL, version 2. See 10 * the COPYING file in the top-level directory. 11 * 12 */ 13 14 #include "qemu/osdep.h" 15 #include "qapi/error.h" 16 #include "cpu.h" 17 #include "trace.h" 18 #include "qemu/error-report.h" 19 #include "qemu/log.h" 20 #include "qemu/main-loop.h" 21 #include "qemu/module.h" 22 #include "hw/virtio/virtio.h" 23 #include "migration/qemu-file-types.h" 24 #include "qemu/atomic.h" 25 #include "hw/virtio/virtio-bus.h" 26 #include "hw/qdev-properties.h" 27 #include "hw/virtio/virtio-access.h" 28 #include "sysemu/dma.h" 29 #include "sysemu/runstate.h" 30 #include "standard-headers/linux/virtio_ids.h" 31 32 /* 33 * The alignment to use between consumer and producer parts of vring. 34 * x86 pagesize again. This is the default, used by transports like PCI 35 * which don't provide a means for the guest to tell the host the alignment. 36 */ 37 #define VIRTIO_PCI_VRING_ALIGN 4096 38 39 typedef struct VRingDesc 40 { 41 uint64_t addr; 42 uint32_t len; 43 uint16_t flags; 44 uint16_t next; 45 } VRingDesc; 46 47 typedef struct VRingPackedDesc { 48 uint64_t addr; 49 uint32_t len; 50 uint16_t id; 51 uint16_t flags; 52 } VRingPackedDesc; 53 54 typedef struct VRingAvail 55 { 56 uint16_t flags; 57 uint16_t idx; 58 uint16_t ring[]; 59 } VRingAvail; 60 61 typedef struct VRingUsedElem 62 { 63 uint32_t id; 64 uint32_t len; 65 } VRingUsedElem; 66 67 typedef struct VRingUsed 68 { 69 uint16_t flags; 70 uint16_t idx; 71 VRingUsedElem ring[]; 72 } VRingUsed; 73 74 typedef struct VRingMemoryRegionCaches { 75 struct rcu_head rcu; 76 MemoryRegionCache desc; 77 MemoryRegionCache avail; 78 MemoryRegionCache used; 79 } VRingMemoryRegionCaches; 80 81 typedef struct VRing 82 { 83 unsigned int num; 84 unsigned int num_default; 85 unsigned int align; 86 hwaddr desc; 87 hwaddr avail; 88 hwaddr used; 89 VRingMemoryRegionCaches *caches; 90 } VRing; 91 92 typedef struct VRingPackedDescEvent { 93 uint16_t off_wrap; 94 uint16_t flags; 95 } VRingPackedDescEvent ; 96 97 struct VirtQueue 98 { 99 VRing vring; 100 VirtQueueElement *used_elems; 101 102 /* Next head to pop */ 103 uint16_t last_avail_idx; 104 bool last_avail_wrap_counter; 105 106 /* Last avail_idx read from VQ. */ 107 uint16_t shadow_avail_idx; 108 bool shadow_avail_wrap_counter; 109 110 uint16_t used_idx; 111 bool used_wrap_counter; 112 113 /* Last used index value we have signalled on */ 114 uint16_t signalled_used; 115 116 /* Last used index value we have signalled on */ 117 bool signalled_used_valid; 118 119 /* Notification enabled? */ 120 bool notification; 121 122 uint16_t queue_index; 123 124 unsigned int inuse; 125 126 uint16_t vector; 127 VirtIOHandleOutput handle_output; 128 VirtIOHandleAIOOutput handle_aio_output; 129 VirtIODevice *vdev; 130 EventNotifier guest_notifier; 131 EventNotifier host_notifier; 132 bool host_notifier_enabled; 133 QLIST_ENTRY(VirtQueue) node; 134 }; 135 136 /* Called within call_rcu(). */ 137 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches) 138 { 139 assert(caches != NULL); 140 address_space_cache_destroy(&caches->desc); 141 address_space_cache_destroy(&caches->avail); 142 address_space_cache_destroy(&caches->used); 143 g_free(caches); 144 } 145 146 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq) 147 { 148 VRingMemoryRegionCaches *caches; 149 150 caches = qatomic_read(&vq->vring.caches); 151 qatomic_rcu_set(&vq->vring.caches, NULL); 152 if (caches) { 153 call_rcu(caches, virtio_free_region_cache, rcu); 154 } 155 } 156 157 static void virtio_init_region_cache(VirtIODevice *vdev, int n) 158 { 159 VirtQueue *vq = &vdev->vq[n]; 160 VRingMemoryRegionCaches *old = vq->vring.caches; 161 VRingMemoryRegionCaches *new = NULL; 162 hwaddr addr, size; 163 int64_t len; 164 bool packed; 165 166 167 addr = vq->vring.desc; 168 if (!addr) { 169 goto out_no_cache; 170 } 171 new = g_new0(VRingMemoryRegionCaches, 1); 172 size = virtio_queue_get_desc_size(vdev, n); 173 packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ? 174 true : false; 175 len = address_space_cache_init(&new->desc, vdev->dma_as, 176 addr, size, packed); 177 if (len < size) { 178 virtio_error(vdev, "Cannot map desc"); 179 goto err_desc; 180 } 181 182 size = virtio_queue_get_used_size(vdev, n); 183 len = address_space_cache_init(&new->used, vdev->dma_as, 184 vq->vring.used, size, true); 185 if (len < size) { 186 virtio_error(vdev, "Cannot map used"); 187 goto err_used; 188 } 189 190 size = virtio_queue_get_avail_size(vdev, n); 191 len = address_space_cache_init(&new->avail, vdev->dma_as, 192 vq->vring.avail, size, false); 193 if (len < size) { 194 virtio_error(vdev, "Cannot map avail"); 195 goto err_avail; 196 } 197 198 qatomic_rcu_set(&vq->vring.caches, new); 199 if (old) { 200 call_rcu(old, virtio_free_region_cache, rcu); 201 } 202 return; 203 204 err_avail: 205 address_space_cache_destroy(&new->avail); 206 err_used: 207 address_space_cache_destroy(&new->used); 208 err_desc: 209 address_space_cache_destroy(&new->desc); 210 out_no_cache: 211 g_free(new); 212 virtio_virtqueue_reset_region_cache(vq); 213 } 214 215 /* virt queue functions */ 216 void virtio_queue_update_rings(VirtIODevice *vdev, int n) 217 { 218 VRing *vring = &vdev->vq[n].vring; 219 220 if (!vring->num || !vring->desc || !vring->align) { 221 /* not yet setup -> nothing to do */ 222 return; 223 } 224 vring->avail = vring->desc + vring->num * sizeof(VRingDesc); 225 vring->used = vring_align(vring->avail + 226 offsetof(VRingAvail, ring[vring->num]), 227 vring->align); 228 virtio_init_region_cache(vdev, n); 229 } 230 231 /* Called within rcu_read_lock(). */ 232 static void vring_split_desc_read(VirtIODevice *vdev, VRingDesc *desc, 233 MemoryRegionCache *cache, int i) 234 { 235 address_space_read_cached(cache, i * sizeof(VRingDesc), 236 desc, sizeof(VRingDesc)); 237 virtio_tswap64s(vdev, &desc->addr); 238 virtio_tswap32s(vdev, &desc->len); 239 virtio_tswap16s(vdev, &desc->flags); 240 virtio_tswap16s(vdev, &desc->next); 241 } 242 243 static void vring_packed_event_read(VirtIODevice *vdev, 244 MemoryRegionCache *cache, 245 VRingPackedDescEvent *e) 246 { 247 hwaddr off_off = offsetof(VRingPackedDescEvent, off_wrap); 248 hwaddr off_flags = offsetof(VRingPackedDescEvent, flags); 249 250 address_space_read_cached(cache, off_flags, &e->flags, 251 sizeof(e->flags)); 252 /* Make sure flags is seen before off_wrap */ 253 smp_rmb(); 254 address_space_read_cached(cache, off_off, &e->off_wrap, 255 sizeof(e->off_wrap)); 256 virtio_tswap16s(vdev, &e->off_wrap); 257 virtio_tswap16s(vdev, &e->flags); 258 } 259 260 static void vring_packed_off_wrap_write(VirtIODevice *vdev, 261 MemoryRegionCache *cache, 262 uint16_t off_wrap) 263 { 264 hwaddr off = offsetof(VRingPackedDescEvent, off_wrap); 265 266 virtio_tswap16s(vdev, &off_wrap); 267 address_space_write_cached(cache, off, &off_wrap, sizeof(off_wrap)); 268 address_space_cache_invalidate(cache, off, sizeof(off_wrap)); 269 } 270 271 static void vring_packed_flags_write(VirtIODevice *vdev, 272 MemoryRegionCache *cache, uint16_t flags) 273 { 274 hwaddr off = offsetof(VRingPackedDescEvent, flags); 275 276 virtio_tswap16s(vdev, &flags); 277 address_space_write_cached(cache, off, &flags, sizeof(flags)); 278 address_space_cache_invalidate(cache, off, sizeof(flags)); 279 } 280 281 /* Called within rcu_read_lock(). */ 282 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq) 283 { 284 return qatomic_rcu_read(&vq->vring.caches); 285 } 286 287 /* Called within rcu_read_lock(). */ 288 static inline uint16_t vring_avail_flags(VirtQueue *vq) 289 { 290 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 291 hwaddr pa = offsetof(VRingAvail, flags); 292 293 if (!caches) { 294 return 0; 295 } 296 297 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); 298 } 299 300 /* Called within rcu_read_lock(). */ 301 static inline uint16_t vring_avail_idx(VirtQueue *vq) 302 { 303 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 304 hwaddr pa = offsetof(VRingAvail, idx); 305 306 if (!caches) { 307 return 0; 308 } 309 310 vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); 311 return vq->shadow_avail_idx; 312 } 313 314 /* Called within rcu_read_lock(). */ 315 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) 316 { 317 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 318 hwaddr pa = offsetof(VRingAvail, ring[i]); 319 320 if (!caches) { 321 return 0; 322 } 323 324 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa); 325 } 326 327 /* Called within rcu_read_lock(). */ 328 static inline uint16_t vring_get_used_event(VirtQueue *vq) 329 { 330 return vring_avail_ring(vq, vq->vring.num); 331 } 332 333 /* Called within rcu_read_lock(). */ 334 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem, 335 int i) 336 { 337 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 338 hwaddr pa = offsetof(VRingUsed, ring[i]); 339 340 if (!caches) { 341 return; 342 } 343 344 virtio_tswap32s(vq->vdev, &uelem->id); 345 virtio_tswap32s(vq->vdev, &uelem->len); 346 address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem)); 347 address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem)); 348 } 349 350 /* Called within rcu_read_lock(). */ 351 static uint16_t vring_used_idx(VirtQueue *vq) 352 { 353 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 354 hwaddr pa = offsetof(VRingUsed, idx); 355 356 if (!caches) { 357 return 0; 358 } 359 360 return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); 361 } 362 363 /* Called within rcu_read_lock(). */ 364 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val) 365 { 366 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 367 hwaddr pa = offsetof(VRingUsed, idx); 368 369 if (caches) { 370 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val); 371 address_space_cache_invalidate(&caches->used, pa, sizeof(val)); 372 } 373 374 vq->used_idx = val; 375 } 376 377 /* Called within rcu_read_lock(). */ 378 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask) 379 { 380 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 381 VirtIODevice *vdev = vq->vdev; 382 hwaddr pa = offsetof(VRingUsed, flags); 383 uint16_t flags; 384 385 if (!caches) { 386 return; 387 } 388 389 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); 390 virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask); 391 address_space_cache_invalidate(&caches->used, pa, sizeof(flags)); 392 } 393 394 /* Called within rcu_read_lock(). */ 395 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) 396 { 397 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq); 398 VirtIODevice *vdev = vq->vdev; 399 hwaddr pa = offsetof(VRingUsed, flags); 400 uint16_t flags; 401 402 if (!caches) { 403 return; 404 } 405 406 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa); 407 virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask); 408 address_space_cache_invalidate(&caches->used, pa, sizeof(flags)); 409 } 410 411 /* Called within rcu_read_lock(). */ 412 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val) 413 { 414 VRingMemoryRegionCaches *caches; 415 hwaddr pa; 416 if (!vq->notification) { 417 return; 418 } 419 420 caches = vring_get_region_caches(vq); 421 if (!caches) { 422 return; 423 } 424 425 pa = offsetof(VRingUsed, ring[vq->vring.num]); 426 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val); 427 address_space_cache_invalidate(&caches->used, pa, sizeof(val)); 428 } 429 430 static void virtio_queue_split_set_notification(VirtQueue *vq, int enable) 431 { 432 RCU_READ_LOCK_GUARD(); 433 434 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) { 435 vring_set_avail_event(vq, vring_avail_idx(vq)); 436 } else if (enable) { 437 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY); 438 } else { 439 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY); 440 } 441 if (enable) { 442 /* Expose avail event/used flags before caller checks the avail idx. */ 443 smp_mb(); 444 } 445 } 446 447 static void virtio_queue_packed_set_notification(VirtQueue *vq, int enable) 448 { 449 uint16_t off_wrap; 450 VRingPackedDescEvent e; 451 VRingMemoryRegionCaches *caches; 452 453 RCU_READ_LOCK_GUARD(); 454 caches = vring_get_region_caches(vq); 455 if (!caches) { 456 return; 457 } 458 459 vring_packed_event_read(vq->vdev, &caches->used, &e); 460 461 if (!enable) { 462 e.flags = VRING_PACKED_EVENT_FLAG_DISABLE; 463 } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) { 464 off_wrap = vq->shadow_avail_idx | vq->shadow_avail_wrap_counter << 15; 465 vring_packed_off_wrap_write(vq->vdev, &caches->used, off_wrap); 466 /* Make sure off_wrap is wrote before flags */ 467 smp_wmb(); 468 e.flags = VRING_PACKED_EVENT_FLAG_DESC; 469 } else { 470 e.flags = VRING_PACKED_EVENT_FLAG_ENABLE; 471 } 472 473 vring_packed_flags_write(vq->vdev, &caches->used, e.flags); 474 if (enable) { 475 /* Expose avail event/used flags before caller checks the avail idx. */ 476 smp_mb(); 477 } 478 } 479 480 bool virtio_queue_get_notification(VirtQueue *vq) 481 { 482 return vq->notification; 483 } 484 485 void virtio_queue_set_notification(VirtQueue *vq, int enable) 486 { 487 vq->notification = enable; 488 489 if (!vq->vring.desc) { 490 return; 491 } 492 493 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 494 virtio_queue_packed_set_notification(vq, enable); 495 } else { 496 virtio_queue_split_set_notification(vq, enable); 497 } 498 } 499 500 int virtio_queue_ready(VirtQueue *vq) 501 { 502 return vq->vring.avail != 0; 503 } 504 505 static void vring_packed_desc_read_flags(VirtIODevice *vdev, 506 uint16_t *flags, 507 MemoryRegionCache *cache, 508 int i) 509 { 510 address_space_read_cached(cache, 511 i * sizeof(VRingPackedDesc) + 512 offsetof(VRingPackedDesc, flags), 513 flags, sizeof(*flags)); 514 virtio_tswap16s(vdev, flags); 515 } 516 517 static void vring_packed_desc_read(VirtIODevice *vdev, 518 VRingPackedDesc *desc, 519 MemoryRegionCache *cache, 520 int i, bool strict_order) 521 { 522 hwaddr off = i * sizeof(VRingPackedDesc); 523 524 vring_packed_desc_read_flags(vdev, &desc->flags, cache, i); 525 526 if (strict_order) { 527 /* Make sure flags is read before the rest fields. */ 528 smp_rmb(); 529 } 530 531 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, addr), 532 &desc->addr, sizeof(desc->addr)); 533 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, id), 534 &desc->id, sizeof(desc->id)); 535 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, len), 536 &desc->len, sizeof(desc->len)); 537 virtio_tswap64s(vdev, &desc->addr); 538 virtio_tswap16s(vdev, &desc->id); 539 virtio_tswap32s(vdev, &desc->len); 540 } 541 542 static void vring_packed_desc_write_data(VirtIODevice *vdev, 543 VRingPackedDesc *desc, 544 MemoryRegionCache *cache, 545 int i) 546 { 547 hwaddr off_id = i * sizeof(VRingPackedDesc) + 548 offsetof(VRingPackedDesc, id); 549 hwaddr off_len = i * sizeof(VRingPackedDesc) + 550 offsetof(VRingPackedDesc, len); 551 552 virtio_tswap32s(vdev, &desc->len); 553 virtio_tswap16s(vdev, &desc->id); 554 address_space_write_cached(cache, off_id, &desc->id, sizeof(desc->id)); 555 address_space_cache_invalidate(cache, off_id, sizeof(desc->id)); 556 address_space_write_cached(cache, off_len, &desc->len, sizeof(desc->len)); 557 address_space_cache_invalidate(cache, off_len, sizeof(desc->len)); 558 } 559 560 static void vring_packed_desc_write_flags(VirtIODevice *vdev, 561 VRingPackedDesc *desc, 562 MemoryRegionCache *cache, 563 int i) 564 { 565 hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags); 566 567 virtio_tswap16s(vdev, &desc->flags); 568 address_space_write_cached(cache, off, &desc->flags, sizeof(desc->flags)); 569 address_space_cache_invalidate(cache, off, sizeof(desc->flags)); 570 } 571 572 static void vring_packed_desc_write(VirtIODevice *vdev, 573 VRingPackedDesc *desc, 574 MemoryRegionCache *cache, 575 int i, bool strict_order) 576 { 577 vring_packed_desc_write_data(vdev, desc, cache, i); 578 if (strict_order) { 579 /* Make sure data is wrote before flags. */ 580 smp_wmb(); 581 } 582 vring_packed_desc_write_flags(vdev, desc, cache, i); 583 } 584 585 static inline bool is_desc_avail(uint16_t flags, bool wrap_counter) 586 { 587 bool avail, used; 588 589 avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL)); 590 used = !!(flags & (1 << VRING_PACKED_DESC_F_USED)); 591 return (avail != used) && (avail == wrap_counter); 592 } 593 594 /* Fetch avail_idx from VQ memory only when we really need to know if 595 * guest has added some buffers. 596 * Called within rcu_read_lock(). */ 597 static int virtio_queue_empty_rcu(VirtQueue *vq) 598 { 599 if (virtio_device_disabled(vq->vdev)) { 600 return 1; 601 } 602 603 if (unlikely(!vq->vring.avail)) { 604 return 1; 605 } 606 607 if (vq->shadow_avail_idx != vq->last_avail_idx) { 608 return 0; 609 } 610 611 return vring_avail_idx(vq) == vq->last_avail_idx; 612 } 613 614 static int virtio_queue_split_empty(VirtQueue *vq) 615 { 616 bool empty; 617 618 if (virtio_device_disabled(vq->vdev)) { 619 return 1; 620 } 621 622 if (unlikely(!vq->vring.avail)) { 623 return 1; 624 } 625 626 if (vq->shadow_avail_idx != vq->last_avail_idx) { 627 return 0; 628 } 629 630 RCU_READ_LOCK_GUARD(); 631 empty = vring_avail_idx(vq) == vq->last_avail_idx; 632 return empty; 633 } 634 635 /* Called within rcu_read_lock(). */ 636 static int virtio_queue_packed_empty_rcu(VirtQueue *vq) 637 { 638 struct VRingPackedDesc desc; 639 VRingMemoryRegionCaches *cache; 640 641 if (unlikely(!vq->vring.desc)) { 642 return 1; 643 } 644 645 cache = vring_get_region_caches(vq); 646 if (!cache) { 647 return 1; 648 } 649 650 vring_packed_desc_read_flags(vq->vdev, &desc.flags, &cache->desc, 651 vq->last_avail_idx); 652 653 return !is_desc_avail(desc.flags, vq->last_avail_wrap_counter); 654 } 655 656 static int virtio_queue_packed_empty(VirtQueue *vq) 657 { 658 RCU_READ_LOCK_GUARD(); 659 return virtio_queue_packed_empty_rcu(vq); 660 } 661 662 int virtio_queue_empty(VirtQueue *vq) 663 { 664 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 665 return virtio_queue_packed_empty(vq); 666 } else { 667 return virtio_queue_split_empty(vq); 668 } 669 } 670 671 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem, 672 unsigned int len) 673 { 674 AddressSpace *dma_as = vq->vdev->dma_as; 675 unsigned int offset; 676 int i; 677 678 offset = 0; 679 for (i = 0; i < elem->in_num; i++) { 680 size_t size = MIN(len - offset, elem->in_sg[i].iov_len); 681 682 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base, 683 elem->in_sg[i].iov_len, 684 DMA_DIRECTION_FROM_DEVICE, size); 685 686 offset += size; 687 } 688 689 for (i = 0; i < elem->out_num; i++) 690 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base, 691 elem->out_sg[i].iov_len, 692 DMA_DIRECTION_TO_DEVICE, 693 elem->out_sg[i].iov_len); 694 } 695 696 /* virtqueue_detach_element: 697 * @vq: The #VirtQueue 698 * @elem: The #VirtQueueElement 699 * @len: number of bytes written 700 * 701 * Detach the element from the virtqueue. This function is suitable for device 702 * reset or other situations where a #VirtQueueElement is simply freed and will 703 * not be pushed or discarded. 704 */ 705 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem, 706 unsigned int len) 707 { 708 vq->inuse -= elem->ndescs; 709 virtqueue_unmap_sg(vq, elem, len); 710 } 711 712 static void virtqueue_split_rewind(VirtQueue *vq, unsigned int num) 713 { 714 vq->last_avail_idx -= num; 715 } 716 717 static void virtqueue_packed_rewind(VirtQueue *vq, unsigned int num) 718 { 719 if (vq->last_avail_idx < num) { 720 vq->last_avail_idx = vq->vring.num + vq->last_avail_idx - num; 721 vq->last_avail_wrap_counter ^= 1; 722 } else { 723 vq->last_avail_idx -= num; 724 } 725 } 726 727 /* virtqueue_unpop: 728 * @vq: The #VirtQueue 729 * @elem: The #VirtQueueElement 730 * @len: number of bytes written 731 * 732 * Pretend the most recent element wasn't popped from the virtqueue. The next 733 * call to virtqueue_pop() will refetch the element. 734 */ 735 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem, 736 unsigned int len) 737 { 738 739 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 740 virtqueue_packed_rewind(vq, 1); 741 } else { 742 virtqueue_split_rewind(vq, 1); 743 } 744 745 virtqueue_detach_element(vq, elem, len); 746 } 747 748 /* virtqueue_rewind: 749 * @vq: The #VirtQueue 750 * @num: Number of elements to push back 751 * 752 * Pretend that elements weren't popped from the virtqueue. The next 753 * virtqueue_pop() will refetch the oldest element. 754 * 755 * Use virtqueue_unpop() instead if you have a VirtQueueElement. 756 * 757 * Returns: true on success, false if @num is greater than the number of in use 758 * elements. 759 */ 760 bool virtqueue_rewind(VirtQueue *vq, unsigned int num) 761 { 762 if (num > vq->inuse) { 763 return false; 764 } 765 766 vq->inuse -= num; 767 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 768 virtqueue_packed_rewind(vq, num); 769 } else { 770 virtqueue_split_rewind(vq, num); 771 } 772 return true; 773 } 774 775 static void virtqueue_split_fill(VirtQueue *vq, const VirtQueueElement *elem, 776 unsigned int len, unsigned int idx) 777 { 778 VRingUsedElem uelem; 779 780 if (unlikely(!vq->vring.used)) { 781 return; 782 } 783 784 idx = (idx + vq->used_idx) % vq->vring.num; 785 786 uelem.id = elem->index; 787 uelem.len = len; 788 vring_used_write(vq, &uelem, idx); 789 } 790 791 static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem, 792 unsigned int len, unsigned int idx) 793 { 794 vq->used_elems[idx].index = elem->index; 795 vq->used_elems[idx].len = len; 796 vq->used_elems[idx].ndescs = elem->ndescs; 797 } 798 799 static void virtqueue_packed_fill_desc(VirtQueue *vq, 800 const VirtQueueElement *elem, 801 unsigned int idx, 802 bool strict_order) 803 { 804 uint16_t head; 805 VRingMemoryRegionCaches *caches; 806 VRingPackedDesc desc = { 807 .id = elem->index, 808 .len = elem->len, 809 }; 810 bool wrap_counter = vq->used_wrap_counter; 811 812 if (unlikely(!vq->vring.desc)) { 813 return; 814 } 815 816 head = vq->used_idx + idx; 817 if (head >= vq->vring.num) { 818 head -= vq->vring.num; 819 wrap_counter ^= 1; 820 } 821 if (wrap_counter) { 822 desc.flags |= (1 << VRING_PACKED_DESC_F_AVAIL); 823 desc.flags |= (1 << VRING_PACKED_DESC_F_USED); 824 } else { 825 desc.flags &= ~(1 << VRING_PACKED_DESC_F_AVAIL); 826 desc.flags &= ~(1 << VRING_PACKED_DESC_F_USED); 827 } 828 829 caches = vring_get_region_caches(vq); 830 if (!caches) { 831 return; 832 } 833 834 vring_packed_desc_write(vq->vdev, &desc, &caches->desc, head, strict_order); 835 } 836 837 /* Called within rcu_read_lock(). */ 838 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, 839 unsigned int len, unsigned int idx) 840 { 841 trace_virtqueue_fill(vq, elem, len, idx); 842 843 virtqueue_unmap_sg(vq, elem, len); 844 845 if (virtio_device_disabled(vq->vdev)) { 846 return; 847 } 848 849 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 850 virtqueue_packed_fill(vq, elem, len, idx); 851 } else { 852 virtqueue_split_fill(vq, elem, len, idx); 853 } 854 } 855 856 /* Called within rcu_read_lock(). */ 857 static void virtqueue_split_flush(VirtQueue *vq, unsigned int count) 858 { 859 uint16_t old, new; 860 861 if (unlikely(!vq->vring.used)) { 862 return; 863 } 864 865 /* Make sure buffer is written before we update index. */ 866 smp_wmb(); 867 trace_virtqueue_flush(vq, count); 868 old = vq->used_idx; 869 new = old + count; 870 vring_used_idx_set(vq, new); 871 vq->inuse -= count; 872 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) 873 vq->signalled_used_valid = false; 874 } 875 876 static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count) 877 { 878 unsigned int i, ndescs = 0; 879 880 if (unlikely(!vq->vring.desc)) { 881 return; 882 } 883 884 for (i = 1; i < count; i++) { 885 virtqueue_packed_fill_desc(vq, &vq->used_elems[i], i, false); 886 ndescs += vq->used_elems[i].ndescs; 887 } 888 virtqueue_packed_fill_desc(vq, &vq->used_elems[0], 0, true); 889 ndescs += vq->used_elems[0].ndescs; 890 891 vq->inuse -= ndescs; 892 vq->used_idx += ndescs; 893 if (vq->used_idx >= vq->vring.num) { 894 vq->used_idx -= vq->vring.num; 895 vq->used_wrap_counter ^= 1; 896 } 897 } 898 899 void virtqueue_flush(VirtQueue *vq, unsigned int count) 900 { 901 if (virtio_device_disabled(vq->vdev)) { 902 vq->inuse -= count; 903 return; 904 } 905 906 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 907 virtqueue_packed_flush(vq, count); 908 } else { 909 virtqueue_split_flush(vq, count); 910 } 911 } 912 913 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, 914 unsigned int len) 915 { 916 RCU_READ_LOCK_GUARD(); 917 virtqueue_fill(vq, elem, len, 0); 918 virtqueue_flush(vq, 1); 919 } 920 921 /* Called within rcu_read_lock(). */ 922 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) 923 { 924 uint16_t num_heads = vring_avail_idx(vq) - idx; 925 926 /* Check it isn't doing very strange things with descriptor numbers. */ 927 if (num_heads > vq->vring.num) { 928 virtio_error(vq->vdev, "Guest moved used index from %u to %u", 929 idx, vq->shadow_avail_idx); 930 return -EINVAL; 931 } 932 /* On success, callers read a descriptor at vq->last_avail_idx. 933 * Make sure descriptor read does not bypass avail index read. */ 934 if (num_heads) { 935 smp_rmb(); 936 } 937 938 return num_heads; 939 } 940 941 /* Called within rcu_read_lock(). */ 942 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx, 943 unsigned int *head) 944 { 945 /* Grab the next descriptor number they're advertising, and increment 946 * the index we've seen. */ 947 *head = vring_avail_ring(vq, idx % vq->vring.num); 948 949 /* If their number is silly, that's a fatal mistake. */ 950 if (*head >= vq->vring.num) { 951 virtio_error(vq->vdev, "Guest says index %u is available", *head); 952 return false; 953 } 954 955 return true; 956 } 957 958 enum { 959 VIRTQUEUE_READ_DESC_ERROR = -1, 960 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */ 961 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */ 962 }; 963 964 static int virtqueue_split_read_next_desc(VirtIODevice *vdev, VRingDesc *desc, 965 MemoryRegionCache *desc_cache, 966 unsigned int max, unsigned int *next) 967 { 968 /* If this descriptor says it doesn't chain, we're done. */ 969 if (!(desc->flags & VRING_DESC_F_NEXT)) { 970 return VIRTQUEUE_READ_DESC_DONE; 971 } 972 973 /* Check they're not leading us off end of descriptors. */ 974 *next = desc->next; 975 /* Make sure compiler knows to grab that: we don't want it changing! */ 976 smp_wmb(); 977 978 if (*next >= max) { 979 virtio_error(vdev, "Desc next is %u", *next); 980 return VIRTQUEUE_READ_DESC_ERROR; 981 } 982 983 vring_split_desc_read(vdev, desc, desc_cache, *next); 984 return VIRTQUEUE_READ_DESC_MORE; 985 } 986 987 static void virtqueue_split_get_avail_bytes(VirtQueue *vq, 988 unsigned int *in_bytes, unsigned int *out_bytes, 989 unsigned max_in_bytes, unsigned max_out_bytes) 990 { 991 VirtIODevice *vdev = vq->vdev; 992 unsigned int max, idx; 993 unsigned int total_bufs, in_total, out_total; 994 VRingMemoryRegionCaches *caches; 995 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; 996 int64_t len = 0; 997 int rc; 998 999 RCU_READ_LOCK_GUARD(); 1000 1001 idx = vq->last_avail_idx; 1002 total_bufs = in_total = out_total = 0; 1003 1004 max = vq->vring.num; 1005 caches = vring_get_region_caches(vq); 1006 if (!caches) { 1007 goto err; 1008 } 1009 1010 while ((rc = virtqueue_num_heads(vq, idx)) > 0) { 1011 MemoryRegionCache *desc_cache = &caches->desc; 1012 unsigned int num_bufs; 1013 VRingDesc desc; 1014 unsigned int i; 1015 1016 num_bufs = total_bufs; 1017 1018 if (!virtqueue_get_head(vq, idx++, &i)) { 1019 goto err; 1020 } 1021 1022 vring_split_desc_read(vdev, &desc, desc_cache, i); 1023 1024 if (desc.flags & VRING_DESC_F_INDIRECT) { 1025 if (!desc.len || (desc.len % sizeof(VRingDesc))) { 1026 virtio_error(vdev, "Invalid size for indirect buffer table"); 1027 goto err; 1028 } 1029 1030 /* If we've got too many, that implies a descriptor loop. */ 1031 if (num_bufs >= max) { 1032 virtio_error(vdev, "Looped descriptor"); 1033 goto err; 1034 } 1035 1036 /* loop over the indirect descriptor table */ 1037 len = address_space_cache_init(&indirect_desc_cache, 1038 vdev->dma_as, 1039 desc.addr, desc.len, false); 1040 desc_cache = &indirect_desc_cache; 1041 if (len < desc.len) { 1042 virtio_error(vdev, "Cannot map indirect buffer"); 1043 goto err; 1044 } 1045 1046 max = desc.len / sizeof(VRingDesc); 1047 num_bufs = i = 0; 1048 vring_split_desc_read(vdev, &desc, desc_cache, i); 1049 } 1050 1051 do { 1052 /* If we've got too many, that implies a descriptor loop. */ 1053 if (++num_bufs > max) { 1054 virtio_error(vdev, "Looped descriptor"); 1055 goto err; 1056 } 1057 1058 if (desc.flags & VRING_DESC_F_WRITE) { 1059 in_total += desc.len; 1060 } else { 1061 out_total += desc.len; 1062 } 1063 if (in_total >= max_in_bytes && out_total >= max_out_bytes) { 1064 goto done; 1065 } 1066 1067 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i); 1068 } while (rc == VIRTQUEUE_READ_DESC_MORE); 1069 1070 if (rc == VIRTQUEUE_READ_DESC_ERROR) { 1071 goto err; 1072 } 1073 1074 if (desc_cache == &indirect_desc_cache) { 1075 address_space_cache_destroy(&indirect_desc_cache); 1076 total_bufs++; 1077 } else { 1078 total_bufs = num_bufs; 1079 } 1080 } 1081 1082 if (rc < 0) { 1083 goto err; 1084 } 1085 1086 done: 1087 address_space_cache_destroy(&indirect_desc_cache); 1088 if (in_bytes) { 1089 *in_bytes = in_total; 1090 } 1091 if (out_bytes) { 1092 *out_bytes = out_total; 1093 } 1094 return; 1095 1096 err: 1097 in_total = out_total = 0; 1098 goto done; 1099 } 1100 1101 static int virtqueue_packed_read_next_desc(VirtQueue *vq, 1102 VRingPackedDesc *desc, 1103 MemoryRegionCache 1104 *desc_cache, 1105 unsigned int max, 1106 unsigned int *next, 1107 bool indirect) 1108 { 1109 /* If this descriptor says it doesn't chain, we're done. */ 1110 if (!indirect && !(desc->flags & VRING_DESC_F_NEXT)) { 1111 return VIRTQUEUE_READ_DESC_DONE; 1112 } 1113 1114 ++*next; 1115 if (*next == max) { 1116 if (indirect) { 1117 return VIRTQUEUE_READ_DESC_DONE; 1118 } else { 1119 (*next) -= vq->vring.num; 1120 } 1121 } 1122 1123 vring_packed_desc_read(vq->vdev, desc, desc_cache, *next, false); 1124 return VIRTQUEUE_READ_DESC_MORE; 1125 } 1126 1127 static void virtqueue_packed_get_avail_bytes(VirtQueue *vq, 1128 unsigned int *in_bytes, 1129 unsigned int *out_bytes, 1130 unsigned max_in_bytes, 1131 unsigned max_out_bytes) 1132 { 1133 VirtIODevice *vdev = vq->vdev; 1134 unsigned int max, idx; 1135 unsigned int total_bufs, in_total, out_total; 1136 MemoryRegionCache *desc_cache; 1137 VRingMemoryRegionCaches *caches; 1138 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; 1139 int64_t len = 0; 1140 VRingPackedDesc desc; 1141 bool wrap_counter; 1142 1143 RCU_READ_LOCK_GUARD(); 1144 idx = vq->last_avail_idx; 1145 wrap_counter = vq->last_avail_wrap_counter; 1146 total_bufs = in_total = out_total = 0; 1147 1148 max = vq->vring.num; 1149 caches = vring_get_region_caches(vq); 1150 if (!caches) { 1151 goto err; 1152 } 1153 1154 for (;;) { 1155 unsigned int num_bufs = total_bufs; 1156 unsigned int i = idx; 1157 int rc; 1158 1159 desc_cache = &caches->desc; 1160 vring_packed_desc_read(vdev, &desc, desc_cache, idx, true); 1161 if (!is_desc_avail(desc.flags, wrap_counter)) { 1162 break; 1163 } 1164 1165 if (desc.flags & VRING_DESC_F_INDIRECT) { 1166 if (desc.len % sizeof(VRingPackedDesc)) { 1167 virtio_error(vdev, "Invalid size for indirect buffer table"); 1168 goto err; 1169 } 1170 1171 /* If we've got too many, that implies a descriptor loop. */ 1172 if (num_bufs >= max) { 1173 virtio_error(vdev, "Looped descriptor"); 1174 goto err; 1175 } 1176 1177 /* loop over the indirect descriptor table */ 1178 len = address_space_cache_init(&indirect_desc_cache, 1179 vdev->dma_as, 1180 desc.addr, desc.len, false); 1181 desc_cache = &indirect_desc_cache; 1182 if (len < desc.len) { 1183 virtio_error(vdev, "Cannot map indirect buffer"); 1184 goto err; 1185 } 1186 1187 max = desc.len / sizeof(VRingPackedDesc); 1188 num_bufs = i = 0; 1189 vring_packed_desc_read(vdev, &desc, desc_cache, i, false); 1190 } 1191 1192 do { 1193 /* If we've got too many, that implies a descriptor loop. */ 1194 if (++num_bufs > max) { 1195 virtio_error(vdev, "Looped descriptor"); 1196 goto err; 1197 } 1198 1199 if (desc.flags & VRING_DESC_F_WRITE) { 1200 in_total += desc.len; 1201 } else { 1202 out_total += desc.len; 1203 } 1204 if (in_total >= max_in_bytes && out_total >= max_out_bytes) { 1205 goto done; 1206 } 1207 1208 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max, 1209 &i, desc_cache == 1210 &indirect_desc_cache); 1211 } while (rc == VIRTQUEUE_READ_DESC_MORE); 1212 1213 if (desc_cache == &indirect_desc_cache) { 1214 address_space_cache_destroy(&indirect_desc_cache); 1215 total_bufs++; 1216 idx++; 1217 } else { 1218 idx += num_bufs - total_bufs; 1219 total_bufs = num_bufs; 1220 } 1221 1222 if (idx >= vq->vring.num) { 1223 idx -= vq->vring.num; 1224 wrap_counter ^= 1; 1225 } 1226 } 1227 1228 /* Record the index and wrap counter for a kick we want */ 1229 vq->shadow_avail_idx = idx; 1230 vq->shadow_avail_wrap_counter = wrap_counter; 1231 done: 1232 address_space_cache_destroy(&indirect_desc_cache); 1233 if (in_bytes) { 1234 *in_bytes = in_total; 1235 } 1236 if (out_bytes) { 1237 *out_bytes = out_total; 1238 } 1239 return; 1240 1241 err: 1242 in_total = out_total = 0; 1243 goto done; 1244 } 1245 1246 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 1247 unsigned int *out_bytes, 1248 unsigned max_in_bytes, unsigned max_out_bytes) 1249 { 1250 uint16_t desc_size; 1251 VRingMemoryRegionCaches *caches; 1252 1253 if (unlikely(!vq->vring.desc)) { 1254 goto err; 1255 } 1256 1257 caches = vring_get_region_caches(vq); 1258 if (!caches) { 1259 goto err; 1260 } 1261 1262 desc_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ? 1263 sizeof(VRingPackedDesc) : sizeof(VRingDesc); 1264 if (caches->desc.len < vq->vring.num * desc_size) { 1265 virtio_error(vq->vdev, "Cannot map descriptor ring"); 1266 goto err; 1267 } 1268 1269 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 1270 virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes, 1271 max_in_bytes, max_out_bytes); 1272 } else { 1273 virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes, 1274 max_in_bytes, max_out_bytes); 1275 } 1276 1277 return; 1278 err: 1279 if (in_bytes) { 1280 *in_bytes = 0; 1281 } 1282 if (out_bytes) { 1283 *out_bytes = 0; 1284 } 1285 } 1286 1287 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, 1288 unsigned int out_bytes) 1289 { 1290 unsigned int in_total, out_total; 1291 1292 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes); 1293 return in_bytes <= in_total && out_bytes <= out_total; 1294 } 1295 1296 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg, 1297 hwaddr *addr, struct iovec *iov, 1298 unsigned int max_num_sg, bool is_write, 1299 hwaddr pa, size_t sz) 1300 { 1301 bool ok = false; 1302 unsigned num_sg = *p_num_sg; 1303 assert(num_sg <= max_num_sg); 1304 1305 if (!sz) { 1306 virtio_error(vdev, "virtio: zero sized buffers are not allowed"); 1307 goto out; 1308 } 1309 1310 while (sz) { 1311 hwaddr len = sz; 1312 1313 if (num_sg == max_num_sg) { 1314 virtio_error(vdev, "virtio: too many write descriptors in " 1315 "indirect table"); 1316 goto out; 1317 } 1318 1319 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len, 1320 is_write ? 1321 DMA_DIRECTION_FROM_DEVICE : 1322 DMA_DIRECTION_TO_DEVICE); 1323 if (!iov[num_sg].iov_base) { 1324 virtio_error(vdev, "virtio: bogus descriptor or out of resources"); 1325 goto out; 1326 } 1327 1328 iov[num_sg].iov_len = len; 1329 addr[num_sg] = pa; 1330 1331 sz -= len; 1332 pa += len; 1333 num_sg++; 1334 } 1335 ok = true; 1336 1337 out: 1338 *p_num_sg = num_sg; 1339 return ok; 1340 } 1341 1342 /* Only used by error code paths before we have a VirtQueueElement (therefore 1343 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to 1344 * yet. 1345 */ 1346 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num, 1347 struct iovec *iov) 1348 { 1349 unsigned int i; 1350 1351 for (i = 0; i < out_num + in_num; i++) { 1352 int is_write = i >= out_num; 1353 1354 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0); 1355 iov++; 1356 } 1357 } 1358 1359 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg, 1360 hwaddr *addr, unsigned int num_sg, 1361 bool is_write) 1362 { 1363 unsigned int i; 1364 hwaddr len; 1365 1366 for (i = 0; i < num_sg; i++) { 1367 len = sg[i].iov_len; 1368 sg[i].iov_base = dma_memory_map(vdev->dma_as, 1369 addr[i], &len, is_write ? 1370 DMA_DIRECTION_FROM_DEVICE : 1371 DMA_DIRECTION_TO_DEVICE); 1372 if (!sg[i].iov_base) { 1373 error_report("virtio: error trying to map MMIO memory"); 1374 exit(1); 1375 } 1376 if (len != sg[i].iov_len) { 1377 error_report("virtio: unexpected memory split"); 1378 exit(1); 1379 } 1380 } 1381 } 1382 1383 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem) 1384 { 1385 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, true); 1386 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num, 1387 false); 1388 } 1389 1390 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num) 1391 { 1392 VirtQueueElement *elem; 1393 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0])); 1394 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]); 1395 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]); 1396 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0])); 1397 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]); 1398 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]); 1399 1400 assert(sz >= sizeof(VirtQueueElement)); 1401 elem = g_malloc(out_sg_end); 1402 trace_virtqueue_alloc_element(elem, sz, in_num, out_num); 1403 elem->out_num = out_num; 1404 elem->in_num = in_num; 1405 elem->in_addr = (void *)elem + in_addr_ofs; 1406 elem->out_addr = (void *)elem + out_addr_ofs; 1407 elem->in_sg = (void *)elem + in_sg_ofs; 1408 elem->out_sg = (void *)elem + out_sg_ofs; 1409 return elem; 1410 } 1411 1412 static void *virtqueue_split_pop(VirtQueue *vq, size_t sz) 1413 { 1414 unsigned int i, head, max; 1415 VRingMemoryRegionCaches *caches; 1416 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; 1417 MemoryRegionCache *desc_cache; 1418 int64_t len; 1419 VirtIODevice *vdev = vq->vdev; 1420 VirtQueueElement *elem = NULL; 1421 unsigned out_num, in_num, elem_entries; 1422 hwaddr addr[VIRTQUEUE_MAX_SIZE]; 1423 struct iovec iov[VIRTQUEUE_MAX_SIZE]; 1424 VRingDesc desc; 1425 int rc; 1426 1427 RCU_READ_LOCK_GUARD(); 1428 if (virtio_queue_empty_rcu(vq)) { 1429 goto done; 1430 } 1431 /* Needed after virtio_queue_empty(), see comment in 1432 * virtqueue_num_heads(). */ 1433 smp_rmb(); 1434 1435 /* When we start there are none of either input nor output. */ 1436 out_num = in_num = elem_entries = 0; 1437 1438 max = vq->vring.num; 1439 1440 if (vq->inuse >= vq->vring.num) { 1441 virtio_error(vdev, "Virtqueue size exceeded"); 1442 goto done; 1443 } 1444 1445 if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) { 1446 goto done; 1447 } 1448 1449 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { 1450 vring_set_avail_event(vq, vq->last_avail_idx); 1451 } 1452 1453 i = head; 1454 1455 caches = vring_get_region_caches(vq); 1456 if (!caches) { 1457 virtio_error(vdev, "Region caches not initialized"); 1458 goto done; 1459 } 1460 1461 if (caches->desc.len < max * sizeof(VRingDesc)) { 1462 virtio_error(vdev, "Cannot map descriptor ring"); 1463 goto done; 1464 } 1465 1466 desc_cache = &caches->desc; 1467 vring_split_desc_read(vdev, &desc, desc_cache, i); 1468 if (desc.flags & VRING_DESC_F_INDIRECT) { 1469 if (!desc.len || (desc.len % sizeof(VRingDesc))) { 1470 virtio_error(vdev, "Invalid size for indirect buffer table"); 1471 goto done; 1472 } 1473 1474 /* loop over the indirect descriptor table */ 1475 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as, 1476 desc.addr, desc.len, false); 1477 desc_cache = &indirect_desc_cache; 1478 if (len < desc.len) { 1479 virtio_error(vdev, "Cannot map indirect buffer"); 1480 goto done; 1481 } 1482 1483 max = desc.len / sizeof(VRingDesc); 1484 i = 0; 1485 vring_split_desc_read(vdev, &desc, desc_cache, i); 1486 } 1487 1488 /* Collect all the descriptors */ 1489 do { 1490 bool map_ok; 1491 1492 if (desc.flags & VRING_DESC_F_WRITE) { 1493 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num, 1494 iov + out_num, 1495 VIRTQUEUE_MAX_SIZE - out_num, true, 1496 desc.addr, desc.len); 1497 } else { 1498 if (in_num) { 1499 virtio_error(vdev, "Incorrect order for descriptors"); 1500 goto err_undo_map; 1501 } 1502 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov, 1503 VIRTQUEUE_MAX_SIZE, false, 1504 desc.addr, desc.len); 1505 } 1506 if (!map_ok) { 1507 goto err_undo_map; 1508 } 1509 1510 /* If we've got too many, that implies a descriptor loop. */ 1511 if (++elem_entries > max) { 1512 virtio_error(vdev, "Looped descriptor"); 1513 goto err_undo_map; 1514 } 1515 1516 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i); 1517 } while (rc == VIRTQUEUE_READ_DESC_MORE); 1518 1519 if (rc == VIRTQUEUE_READ_DESC_ERROR) { 1520 goto err_undo_map; 1521 } 1522 1523 /* Now copy what we have collected and mapped */ 1524 elem = virtqueue_alloc_element(sz, out_num, in_num); 1525 elem->index = head; 1526 elem->ndescs = 1; 1527 for (i = 0; i < out_num; i++) { 1528 elem->out_addr[i] = addr[i]; 1529 elem->out_sg[i] = iov[i]; 1530 } 1531 for (i = 0; i < in_num; i++) { 1532 elem->in_addr[i] = addr[out_num + i]; 1533 elem->in_sg[i] = iov[out_num + i]; 1534 } 1535 1536 vq->inuse++; 1537 1538 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); 1539 done: 1540 address_space_cache_destroy(&indirect_desc_cache); 1541 1542 return elem; 1543 1544 err_undo_map: 1545 virtqueue_undo_map_desc(out_num, in_num, iov); 1546 goto done; 1547 } 1548 1549 static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz) 1550 { 1551 unsigned int i, max; 1552 VRingMemoryRegionCaches *caches; 1553 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID; 1554 MemoryRegionCache *desc_cache; 1555 int64_t len; 1556 VirtIODevice *vdev = vq->vdev; 1557 VirtQueueElement *elem = NULL; 1558 unsigned out_num, in_num, elem_entries; 1559 hwaddr addr[VIRTQUEUE_MAX_SIZE]; 1560 struct iovec iov[VIRTQUEUE_MAX_SIZE]; 1561 VRingPackedDesc desc; 1562 uint16_t id; 1563 int rc; 1564 1565 RCU_READ_LOCK_GUARD(); 1566 if (virtio_queue_packed_empty_rcu(vq)) { 1567 goto done; 1568 } 1569 1570 /* When we start there are none of either input nor output. */ 1571 out_num = in_num = elem_entries = 0; 1572 1573 max = vq->vring.num; 1574 1575 if (vq->inuse >= vq->vring.num) { 1576 virtio_error(vdev, "Virtqueue size exceeded"); 1577 goto done; 1578 } 1579 1580 i = vq->last_avail_idx; 1581 1582 caches = vring_get_region_caches(vq); 1583 if (!caches) { 1584 virtio_error(vdev, "Region caches not initialized"); 1585 goto done; 1586 } 1587 1588 if (caches->desc.len < max * sizeof(VRingDesc)) { 1589 virtio_error(vdev, "Cannot map descriptor ring"); 1590 goto done; 1591 } 1592 1593 desc_cache = &caches->desc; 1594 vring_packed_desc_read(vdev, &desc, desc_cache, i, true); 1595 id = desc.id; 1596 if (desc.flags & VRING_DESC_F_INDIRECT) { 1597 if (desc.len % sizeof(VRingPackedDesc)) { 1598 virtio_error(vdev, "Invalid size for indirect buffer table"); 1599 goto done; 1600 } 1601 1602 /* loop over the indirect descriptor table */ 1603 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as, 1604 desc.addr, desc.len, false); 1605 desc_cache = &indirect_desc_cache; 1606 if (len < desc.len) { 1607 virtio_error(vdev, "Cannot map indirect buffer"); 1608 goto done; 1609 } 1610 1611 max = desc.len / sizeof(VRingPackedDesc); 1612 i = 0; 1613 vring_packed_desc_read(vdev, &desc, desc_cache, i, false); 1614 } 1615 1616 /* Collect all the descriptors */ 1617 do { 1618 bool map_ok; 1619 1620 if (desc.flags & VRING_DESC_F_WRITE) { 1621 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num, 1622 iov + out_num, 1623 VIRTQUEUE_MAX_SIZE - out_num, true, 1624 desc.addr, desc.len); 1625 } else { 1626 if (in_num) { 1627 virtio_error(vdev, "Incorrect order for descriptors"); 1628 goto err_undo_map; 1629 } 1630 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov, 1631 VIRTQUEUE_MAX_SIZE, false, 1632 desc.addr, desc.len); 1633 } 1634 if (!map_ok) { 1635 goto err_undo_map; 1636 } 1637 1638 /* If we've got too many, that implies a descriptor loop. */ 1639 if (++elem_entries > max) { 1640 virtio_error(vdev, "Looped descriptor"); 1641 goto err_undo_map; 1642 } 1643 1644 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max, &i, 1645 desc_cache == 1646 &indirect_desc_cache); 1647 } while (rc == VIRTQUEUE_READ_DESC_MORE); 1648 1649 /* Now copy what we have collected and mapped */ 1650 elem = virtqueue_alloc_element(sz, out_num, in_num); 1651 for (i = 0; i < out_num; i++) { 1652 elem->out_addr[i] = addr[i]; 1653 elem->out_sg[i] = iov[i]; 1654 } 1655 for (i = 0; i < in_num; i++) { 1656 elem->in_addr[i] = addr[out_num + i]; 1657 elem->in_sg[i] = iov[out_num + i]; 1658 } 1659 1660 elem->index = id; 1661 elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries; 1662 vq->last_avail_idx += elem->ndescs; 1663 vq->inuse += elem->ndescs; 1664 1665 if (vq->last_avail_idx >= vq->vring.num) { 1666 vq->last_avail_idx -= vq->vring.num; 1667 vq->last_avail_wrap_counter ^= 1; 1668 } 1669 1670 vq->shadow_avail_idx = vq->last_avail_idx; 1671 vq->shadow_avail_wrap_counter = vq->last_avail_wrap_counter; 1672 1673 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); 1674 done: 1675 address_space_cache_destroy(&indirect_desc_cache); 1676 1677 return elem; 1678 1679 err_undo_map: 1680 virtqueue_undo_map_desc(out_num, in_num, iov); 1681 goto done; 1682 } 1683 1684 void *virtqueue_pop(VirtQueue *vq, size_t sz) 1685 { 1686 if (virtio_device_disabled(vq->vdev)) { 1687 return NULL; 1688 } 1689 1690 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) { 1691 return virtqueue_packed_pop(vq, sz); 1692 } else { 1693 return virtqueue_split_pop(vq, sz); 1694 } 1695 } 1696 1697 static unsigned int virtqueue_packed_drop_all(VirtQueue *vq) 1698 { 1699 VRingMemoryRegionCaches *caches; 1700 MemoryRegionCache *desc_cache; 1701 unsigned int dropped = 0; 1702 VirtQueueElement elem = {}; 1703 VirtIODevice *vdev = vq->vdev; 1704 VRingPackedDesc desc; 1705 1706 caches = vring_get_region_caches(vq); 1707 if (!caches) { 1708 return 0; 1709 } 1710 1711 desc_cache = &caches->desc; 1712 1713 virtio_queue_set_notification(vq, 0); 1714 1715 while (vq->inuse < vq->vring.num) { 1716 unsigned int idx = vq->last_avail_idx; 1717 /* 1718 * works similar to virtqueue_pop but does not map buffers 1719 * and does not allocate any memory. 1720 */ 1721 vring_packed_desc_read(vdev, &desc, desc_cache, 1722 vq->last_avail_idx , true); 1723 if (!is_desc_avail(desc.flags, vq->last_avail_wrap_counter)) { 1724 break; 1725 } 1726 elem.index = desc.id; 1727 elem.ndescs = 1; 1728 while (virtqueue_packed_read_next_desc(vq, &desc, desc_cache, 1729 vq->vring.num, &idx, false)) { 1730 ++elem.ndescs; 1731 } 1732 /* 1733 * immediately push the element, nothing to unmap 1734 * as both in_num and out_num are set to 0. 1735 */ 1736 virtqueue_push(vq, &elem, 0); 1737 dropped++; 1738 vq->last_avail_idx += elem.ndescs; 1739 if (vq->last_avail_idx >= vq->vring.num) { 1740 vq->last_avail_idx -= vq->vring.num; 1741 vq->last_avail_wrap_counter ^= 1; 1742 } 1743 } 1744 1745 return dropped; 1746 } 1747 1748 static unsigned int virtqueue_split_drop_all(VirtQueue *vq) 1749 { 1750 unsigned int dropped = 0; 1751 VirtQueueElement elem = {}; 1752 VirtIODevice *vdev = vq->vdev; 1753 bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); 1754 1755 while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) { 1756 /* works similar to virtqueue_pop but does not map buffers 1757 * and does not allocate any memory */ 1758 smp_rmb(); 1759 if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) { 1760 break; 1761 } 1762 vq->inuse++; 1763 vq->last_avail_idx++; 1764 if (fEventIdx) { 1765 vring_set_avail_event(vq, vq->last_avail_idx); 1766 } 1767 /* immediately push the element, nothing to unmap 1768 * as both in_num and out_num are set to 0 */ 1769 virtqueue_push(vq, &elem, 0); 1770 dropped++; 1771 } 1772 1773 return dropped; 1774 } 1775 1776 /* virtqueue_drop_all: 1777 * @vq: The #VirtQueue 1778 * Drops all queued buffers and indicates them to the guest 1779 * as if they are done. Useful when buffers can not be 1780 * processed but must be returned to the guest. 1781 */ 1782 unsigned int virtqueue_drop_all(VirtQueue *vq) 1783 { 1784 struct VirtIODevice *vdev = vq->vdev; 1785 1786 if (virtio_device_disabled(vq->vdev)) { 1787 return 0; 1788 } 1789 1790 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 1791 return virtqueue_packed_drop_all(vq); 1792 } else { 1793 return virtqueue_split_drop_all(vq); 1794 } 1795 } 1796 1797 /* Reading and writing a structure directly to QEMUFile is *awful*, but 1798 * it is what QEMU has always done by mistake. We can change it sooner 1799 * or later by bumping the version number of the affected vm states. 1800 * In the meanwhile, since the in-memory layout of VirtQueueElement 1801 * has changed, we need to marshal to and from the layout that was 1802 * used before the change. 1803 */ 1804 typedef struct VirtQueueElementOld { 1805 unsigned int index; 1806 unsigned int out_num; 1807 unsigned int in_num; 1808 hwaddr in_addr[VIRTQUEUE_MAX_SIZE]; 1809 hwaddr out_addr[VIRTQUEUE_MAX_SIZE]; 1810 struct iovec in_sg[VIRTQUEUE_MAX_SIZE]; 1811 struct iovec out_sg[VIRTQUEUE_MAX_SIZE]; 1812 } VirtQueueElementOld; 1813 1814 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz) 1815 { 1816 VirtQueueElement *elem; 1817 VirtQueueElementOld data; 1818 int i; 1819 1820 qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld)); 1821 1822 /* TODO: teach all callers that this can fail, and return failure instead 1823 * of asserting here. 1824 * This is just one thing (there are probably more) that must be 1825 * fixed before we can allow NDEBUG compilation. 1826 */ 1827 assert(ARRAY_SIZE(data.in_addr) >= data.in_num); 1828 assert(ARRAY_SIZE(data.out_addr) >= data.out_num); 1829 1830 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num); 1831 elem->index = data.index; 1832 1833 for (i = 0; i < elem->in_num; i++) { 1834 elem->in_addr[i] = data.in_addr[i]; 1835 } 1836 1837 for (i = 0; i < elem->out_num; i++) { 1838 elem->out_addr[i] = data.out_addr[i]; 1839 } 1840 1841 for (i = 0; i < elem->in_num; i++) { 1842 /* Base is overwritten by virtqueue_map. */ 1843 elem->in_sg[i].iov_base = 0; 1844 elem->in_sg[i].iov_len = data.in_sg[i].iov_len; 1845 } 1846 1847 for (i = 0; i < elem->out_num; i++) { 1848 /* Base is overwritten by virtqueue_map. */ 1849 elem->out_sg[i].iov_base = 0; 1850 elem->out_sg[i].iov_len = data.out_sg[i].iov_len; 1851 } 1852 1853 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 1854 qemu_get_be32s(f, &elem->ndescs); 1855 } 1856 1857 virtqueue_map(vdev, elem); 1858 return elem; 1859 } 1860 1861 void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, 1862 VirtQueueElement *elem) 1863 { 1864 VirtQueueElementOld data; 1865 int i; 1866 1867 memset(&data, 0, sizeof(data)); 1868 data.index = elem->index; 1869 data.in_num = elem->in_num; 1870 data.out_num = elem->out_num; 1871 1872 for (i = 0; i < elem->in_num; i++) { 1873 data.in_addr[i] = elem->in_addr[i]; 1874 } 1875 1876 for (i = 0; i < elem->out_num; i++) { 1877 data.out_addr[i] = elem->out_addr[i]; 1878 } 1879 1880 for (i = 0; i < elem->in_num; i++) { 1881 /* Base is overwritten by virtqueue_map when loading. Do not 1882 * save it, as it would leak the QEMU address space layout. */ 1883 data.in_sg[i].iov_len = elem->in_sg[i].iov_len; 1884 } 1885 1886 for (i = 0; i < elem->out_num; i++) { 1887 /* Do not save iov_base as above. */ 1888 data.out_sg[i].iov_len = elem->out_sg[i].iov_len; 1889 } 1890 1891 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 1892 qemu_put_be32s(f, &elem->ndescs); 1893 } 1894 1895 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld)); 1896 } 1897 1898 /* virtio device */ 1899 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector) 1900 { 1901 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1902 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1903 1904 if (virtio_device_disabled(vdev)) { 1905 return; 1906 } 1907 1908 if (k->notify) { 1909 k->notify(qbus->parent, vector); 1910 } 1911 } 1912 1913 void virtio_update_irq(VirtIODevice *vdev) 1914 { 1915 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); 1916 } 1917 1918 static int virtio_validate_features(VirtIODevice *vdev) 1919 { 1920 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1921 1922 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) && 1923 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { 1924 return -EFAULT; 1925 } 1926 1927 if (k->validate_features) { 1928 return k->validate_features(vdev); 1929 } else { 1930 return 0; 1931 } 1932 } 1933 1934 int virtio_set_status(VirtIODevice *vdev, uint8_t val) 1935 { 1936 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1937 trace_virtio_set_status(vdev, val); 1938 1939 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 1940 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) && 1941 val & VIRTIO_CONFIG_S_FEATURES_OK) { 1942 int ret = virtio_validate_features(vdev); 1943 1944 if (ret) { 1945 return ret; 1946 } 1947 } 1948 } 1949 1950 if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) != 1951 (val & VIRTIO_CONFIG_S_DRIVER_OK)) { 1952 virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK); 1953 } 1954 1955 if (k->set_status) { 1956 k->set_status(vdev, val); 1957 } 1958 vdev->status = val; 1959 1960 return 0; 1961 } 1962 1963 static enum virtio_device_endian virtio_default_endian(void) 1964 { 1965 if (target_words_bigendian()) { 1966 return VIRTIO_DEVICE_ENDIAN_BIG; 1967 } else { 1968 return VIRTIO_DEVICE_ENDIAN_LITTLE; 1969 } 1970 } 1971 1972 static enum virtio_device_endian virtio_current_cpu_endian(void) 1973 { 1974 if (cpu_virtio_is_big_endian(current_cpu)) { 1975 return VIRTIO_DEVICE_ENDIAN_BIG; 1976 } else { 1977 return VIRTIO_DEVICE_ENDIAN_LITTLE; 1978 } 1979 } 1980 1981 void virtio_reset(void *opaque) 1982 { 1983 VirtIODevice *vdev = opaque; 1984 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1985 int i; 1986 1987 virtio_set_status(vdev, 0); 1988 if (current_cpu) { 1989 /* Guest initiated reset */ 1990 vdev->device_endian = virtio_current_cpu_endian(); 1991 } else { 1992 /* System reset */ 1993 vdev->device_endian = virtio_default_endian(); 1994 } 1995 1996 if (k->reset) { 1997 k->reset(vdev); 1998 } 1999 2000 vdev->start_on_kick = false; 2001 vdev->started = false; 2002 vdev->broken = false; 2003 vdev->guest_features = 0; 2004 vdev->queue_sel = 0; 2005 vdev->status = 0; 2006 vdev->disabled = false; 2007 qatomic_set(&vdev->isr, 0); 2008 vdev->config_vector = VIRTIO_NO_VECTOR; 2009 virtio_notify_vector(vdev, vdev->config_vector); 2010 2011 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2012 vdev->vq[i].vring.desc = 0; 2013 vdev->vq[i].vring.avail = 0; 2014 vdev->vq[i].vring.used = 0; 2015 vdev->vq[i].last_avail_idx = 0; 2016 vdev->vq[i].shadow_avail_idx = 0; 2017 vdev->vq[i].used_idx = 0; 2018 vdev->vq[i].last_avail_wrap_counter = true; 2019 vdev->vq[i].shadow_avail_wrap_counter = true; 2020 vdev->vq[i].used_wrap_counter = true; 2021 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR); 2022 vdev->vq[i].signalled_used = 0; 2023 vdev->vq[i].signalled_used_valid = false; 2024 vdev->vq[i].notification = true; 2025 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default; 2026 vdev->vq[i].inuse = 0; 2027 virtio_virtqueue_reset_region_cache(&vdev->vq[i]); 2028 } 2029 } 2030 2031 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) 2032 { 2033 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2034 uint8_t val; 2035 2036 if (addr + sizeof(val) > vdev->config_len) { 2037 return (uint32_t)-1; 2038 } 2039 2040 k->get_config(vdev, vdev->config); 2041 2042 val = ldub_p(vdev->config + addr); 2043 return val; 2044 } 2045 2046 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) 2047 { 2048 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2049 uint16_t val; 2050 2051 if (addr + sizeof(val) > vdev->config_len) { 2052 return (uint32_t)-1; 2053 } 2054 2055 k->get_config(vdev, vdev->config); 2056 2057 val = lduw_p(vdev->config + addr); 2058 return val; 2059 } 2060 2061 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) 2062 { 2063 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2064 uint32_t val; 2065 2066 if (addr + sizeof(val) > vdev->config_len) { 2067 return (uint32_t)-1; 2068 } 2069 2070 k->get_config(vdev, vdev->config); 2071 2072 val = ldl_p(vdev->config + addr); 2073 return val; 2074 } 2075 2076 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) 2077 { 2078 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2079 uint8_t val = data; 2080 2081 if (addr + sizeof(val) > vdev->config_len) { 2082 return; 2083 } 2084 2085 stb_p(vdev->config + addr, val); 2086 2087 if (k->set_config) { 2088 k->set_config(vdev, vdev->config); 2089 } 2090 } 2091 2092 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) 2093 { 2094 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2095 uint16_t val = data; 2096 2097 if (addr + sizeof(val) > vdev->config_len) { 2098 return; 2099 } 2100 2101 stw_p(vdev->config + addr, val); 2102 2103 if (k->set_config) { 2104 k->set_config(vdev, vdev->config); 2105 } 2106 } 2107 2108 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) 2109 { 2110 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2111 uint32_t val = data; 2112 2113 if (addr + sizeof(val) > vdev->config_len) { 2114 return; 2115 } 2116 2117 stl_p(vdev->config + addr, val); 2118 2119 if (k->set_config) { 2120 k->set_config(vdev, vdev->config); 2121 } 2122 } 2123 2124 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr) 2125 { 2126 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2127 uint8_t val; 2128 2129 if (addr + sizeof(val) > vdev->config_len) { 2130 return (uint32_t)-1; 2131 } 2132 2133 k->get_config(vdev, vdev->config); 2134 2135 val = ldub_p(vdev->config + addr); 2136 return val; 2137 } 2138 2139 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr) 2140 { 2141 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2142 uint16_t val; 2143 2144 if (addr + sizeof(val) > vdev->config_len) { 2145 return (uint32_t)-1; 2146 } 2147 2148 k->get_config(vdev, vdev->config); 2149 2150 val = lduw_le_p(vdev->config + addr); 2151 return val; 2152 } 2153 2154 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr) 2155 { 2156 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2157 uint32_t val; 2158 2159 if (addr + sizeof(val) > vdev->config_len) { 2160 return (uint32_t)-1; 2161 } 2162 2163 k->get_config(vdev, vdev->config); 2164 2165 val = ldl_le_p(vdev->config + addr); 2166 return val; 2167 } 2168 2169 void virtio_config_modern_writeb(VirtIODevice *vdev, 2170 uint32_t addr, uint32_t data) 2171 { 2172 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2173 uint8_t val = data; 2174 2175 if (addr + sizeof(val) > vdev->config_len) { 2176 return; 2177 } 2178 2179 stb_p(vdev->config + addr, val); 2180 2181 if (k->set_config) { 2182 k->set_config(vdev, vdev->config); 2183 } 2184 } 2185 2186 void virtio_config_modern_writew(VirtIODevice *vdev, 2187 uint32_t addr, uint32_t data) 2188 { 2189 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2190 uint16_t val = data; 2191 2192 if (addr + sizeof(val) > vdev->config_len) { 2193 return; 2194 } 2195 2196 stw_le_p(vdev->config + addr, val); 2197 2198 if (k->set_config) { 2199 k->set_config(vdev, vdev->config); 2200 } 2201 } 2202 2203 void virtio_config_modern_writel(VirtIODevice *vdev, 2204 uint32_t addr, uint32_t data) 2205 { 2206 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2207 uint32_t val = data; 2208 2209 if (addr + sizeof(val) > vdev->config_len) { 2210 return; 2211 } 2212 2213 stl_le_p(vdev->config + addr, val); 2214 2215 if (k->set_config) { 2216 k->set_config(vdev, vdev->config); 2217 } 2218 } 2219 2220 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr) 2221 { 2222 if (!vdev->vq[n].vring.num) { 2223 return; 2224 } 2225 vdev->vq[n].vring.desc = addr; 2226 virtio_queue_update_rings(vdev, n); 2227 } 2228 2229 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n) 2230 { 2231 return vdev->vq[n].vring.desc; 2232 } 2233 2234 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc, 2235 hwaddr avail, hwaddr used) 2236 { 2237 if (!vdev->vq[n].vring.num) { 2238 return; 2239 } 2240 vdev->vq[n].vring.desc = desc; 2241 vdev->vq[n].vring.avail = avail; 2242 vdev->vq[n].vring.used = used; 2243 virtio_init_region_cache(vdev, n); 2244 } 2245 2246 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num) 2247 { 2248 /* Don't allow guest to flip queue between existent and 2249 * nonexistent states, or to set it to an invalid size. 2250 */ 2251 if (!!num != !!vdev->vq[n].vring.num || 2252 num > VIRTQUEUE_MAX_SIZE || 2253 num < 0) { 2254 return; 2255 } 2256 vdev->vq[n].vring.num = num; 2257 } 2258 2259 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector) 2260 { 2261 return QLIST_FIRST(&vdev->vector_queues[vector]); 2262 } 2263 2264 VirtQueue *virtio_vector_next_queue(VirtQueue *vq) 2265 { 2266 return QLIST_NEXT(vq, node); 2267 } 2268 2269 int virtio_queue_get_num(VirtIODevice *vdev, int n) 2270 { 2271 return vdev->vq[n].vring.num; 2272 } 2273 2274 int virtio_queue_get_max_num(VirtIODevice *vdev, int n) 2275 { 2276 return vdev->vq[n].vring.num_default; 2277 } 2278 2279 int virtio_get_num_queues(VirtIODevice *vdev) 2280 { 2281 int i; 2282 2283 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2284 if (!virtio_queue_get_num(vdev, i)) { 2285 break; 2286 } 2287 } 2288 2289 return i; 2290 } 2291 2292 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align) 2293 { 2294 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2295 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 2296 2297 /* virtio-1 compliant devices cannot change the alignment */ 2298 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 2299 error_report("tried to modify queue alignment for virtio-1 device"); 2300 return; 2301 } 2302 /* Check that the transport told us it was going to do this 2303 * (so a buggy transport will immediately assert rather than 2304 * silently failing to migrate this state) 2305 */ 2306 assert(k->has_variable_vring_alignment); 2307 2308 if (align) { 2309 vdev->vq[n].vring.align = align; 2310 virtio_queue_update_rings(vdev, n); 2311 } 2312 } 2313 2314 static bool virtio_queue_notify_aio_vq(VirtQueue *vq) 2315 { 2316 bool ret = false; 2317 2318 if (vq->vring.desc && vq->handle_aio_output) { 2319 VirtIODevice *vdev = vq->vdev; 2320 2321 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); 2322 ret = vq->handle_aio_output(vdev, vq); 2323 2324 if (unlikely(vdev->start_on_kick)) { 2325 virtio_set_started(vdev, true); 2326 } 2327 } 2328 2329 return ret; 2330 } 2331 2332 static void virtio_queue_notify_vq(VirtQueue *vq) 2333 { 2334 if (vq->vring.desc && vq->handle_output) { 2335 VirtIODevice *vdev = vq->vdev; 2336 2337 if (unlikely(vdev->broken)) { 2338 return; 2339 } 2340 2341 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); 2342 vq->handle_output(vdev, vq); 2343 2344 if (unlikely(vdev->start_on_kick)) { 2345 virtio_set_started(vdev, true); 2346 } 2347 } 2348 } 2349 2350 void virtio_queue_notify(VirtIODevice *vdev, int n) 2351 { 2352 VirtQueue *vq = &vdev->vq[n]; 2353 2354 if (unlikely(!vq->vring.desc || vdev->broken)) { 2355 return; 2356 } 2357 2358 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); 2359 if (vq->host_notifier_enabled) { 2360 event_notifier_set(&vq->host_notifier); 2361 } else if (vq->handle_output) { 2362 vq->handle_output(vdev, vq); 2363 2364 if (unlikely(vdev->start_on_kick)) { 2365 virtio_set_started(vdev, true); 2366 } 2367 } 2368 } 2369 2370 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n) 2371 { 2372 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector : 2373 VIRTIO_NO_VECTOR; 2374 } 2375 2376 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector) 2377 { 2378 VirtQueue *vq = &vdev->vq[n]; 2379 2380 if (n < VIRTIO_QUEUE_MAX) { 2381 if (vdev->vector_queues && 2382 vdev->vq[n].vector != VIRTIO_NO_VECTOR) { 2383 QLIST_REMOVE(vq, node); 2384 } 2385 vdev->vq[n].vector = vector; 2386 if (vdev->vector_queues && 2387 vector != VIRTIO_NO_VECTOR) { 2388 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node); 2389 } 2390 } 2391 } 2392 2393 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, 2394 VirtIOHandleOutput handle_output) 2395 { 2396 int i; 2397 2398 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2399 if (vdev->vq[i].vring.num == 0) 2400 break; 2401 } 2402 2403 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE) 2404 abort(); 2405 2406 vdev->vq[i].vring.num = queue_size; 2407 vdev->vq[i].vring.num_default = queue_size; 2408 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN; 2409 vdev->vq[i].handle_output = handle_output; 2410 vdev->vq[i].handle_aio_output = NULL; 2411 vdev->vq[i].used_elems = g_malloc0(sizeof(VirtQueueElement) * 2412 queue_size); 2413 2414 return &vdev->vq[i]; 2415 } 2416 2417 void virtio_delete_queue(VirtQueue *vq) 2418 { 2419 vq->vring.num = 0; 2420 vq->vring.num_default = 0; 2421 vq->handle_output = NULL; 2422 vq->handle_aio_output = NULL; 2423 g_free(vq->used_elems); 2424 vq->used_elems = NULL; 2425 virtio_virtqueue_reset_region_cache(vq); 2426 } 2427 2428 void virtio_del_queue(VirtIODevice *vdev, int n) 2429 { 2430 if (n < 0 || n >= VIRTIO_QUEUE_MAX) { 2431 abort(); 2432 } 2433 2434 virtio_delete_queue(&vdev->vq[n]); 2435 } 2436 2437 static void virtio_set_isr(VirtIODevice *vdev, int value) 2438 { 2439 uint8_t old = qatomic_read(&vdev->isr); 2440 2441 /* Do not write ISR if it does not change, so that its cacheline remains 2442 * shared in the common case where the guest does not read it. 2443 */ 2444 if ((old & value) != value) { 2445 qatomic_or(&vdev->isr, value); 2446 } 2447 } 2448 2449 /* Called within rcu_read_lock(). */ 2450 static bool virtio_split_should_notify(VirtIODevice *vdev, VirtQueue *vq) 2451 { 2452 uint16_t old, new; 2453 bool v; 2454 /* We need to expose used array entries before checking used event. */ 2455 smp_mb(); 2456 /* Always notify when queue is empty (when feature acknowledge) */ 2457 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) && 2458 !vq->inuse && virtio_queue_empty(vq)) { 2459 return true; 2460 } 2461 2462 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { 2463 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT); 2464 } 2465 2466 v = vq->signalled_used_valid; 2467 vq->signalled_used_valid = true; 2468 old = vq->signalled_used; 2469 new = vq->signalled_used = vq->used_idx; 2470 return !v || vring_need_event(vring_get_used_event(vq), new, old); 2471 } 2472 2473 static bool vring_packed_need_event(VirtQueue *vq, bool wrap, 2474 uint16_t off_wrap, uint16_t new, 2475 uint16_t old) 2476 { 2477 int off = off_wrap & ~(1 << 15); 2478 2479 if (wrap != off_wrap >> 15) { 2480 off -= vq->vring.num; 2481 } 2482 2483 return vring_need_event(off, new, old); 2484 } 2485 2486 /* Called within rcu_read_lock(). */ 2487 static bool virtio_packed_should_notify(VirtIODevice *vdev, VirtQueue *vq) 2488 { 2489 VRingPackedDescEvent e; 2490 uint16_t old, new; 2491 bool v; 2492 VRingMemoryRegionCaches *caches; 2493 2494 caches = vring_get_region_caches(vq); 2495 if (!caches) { 2496 return false; 2497 } 2498 2499 vring_packed_event_read(vdev, &caches->avail, &e); 2500 2501 old = vq->signalled_used; 2502 new = vq->signalled_used = vq->used_idx; 2503 v = vq->signalled_used_valid; 2504 vq->signalled_used_valid = true; 2505 2506 if (e.flags == VRING_PACKED_EVENT_FLAG_DISABLE) { 2507 return false; 2508 } else if (e.flags == VRING_PACKED_EVENT_FLAG_ENABLE) { 2509 return true; 2510 } 2511 2512 return !v || vring_packed_need_event(vq, vq->used_wrap_counter, 2513 e.off_wrap, new, old); 2514 } 2515 2516 /* Called within rcu_read_lock(). */ 2517 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq) 2518 { 2519 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 2520 return virtio_packed_should_notify(vdev, vq); 2521 } else { 2522 return virtio_split_should_notify(vdev, vq); 2523 } 2524 } 2525 2526 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) 2527 { 2528 WITH_RCU_READ_LOCK_GUARD() { 2529 if (!virtio_should_notify(vdev, vq)) { 2530 return; 2531 } 2532 } 2533 2534 trace_virtio_notify_irqfd(vdev, vq); 2535 2536 /* 2537 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but 2538 * windows drivers included in virtio-win 1.8.0 (circa 2015) are 2539 * incorrectly polling this bit during crashdump and hibernation 2540 * in MSI mode, causing a hang if this bit is never updated. 2541 * Recent releases of Windows do not really shut down, but rather 2542 * log out and hibernate to make the next startup faster. Hence, 2543 * this manifested as a more serious hang during shutdown with 2544 * 2545 * Next driver release from 2016 fixed this problem, so working around it 2546 * is not a must, but it's easy to do so let's do it here. 2547 * 2548 * Note: it's safe to update ISR from any thread as it was switched 2549 * to an atomic operation. 2550 */ 2551 virtio_set_isr(vq->vdev, 0x1); 2552 event_notifier_set(&vq->guest_notifier); 2553 } 2554 2555 static void virtio_irq(VirtQueue *vq) 2556 { 2557 virtio_set_isr(vq->vdev, 0x1); 2558 virtio_notify_vector(vq->vdev, vq->vector); 2559 } 2560 2561 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq) 2562 { 2563 WITH_RCU_READ_LOCK_GUARD() { 2564 if (!virtio_should_notify(vdev, vq)) { 2565 return; 2566 } 2567 } 2568 2569 trace_virtio_notify(vdev, vq); 2570 virtio_irq(vq); 2571 } 2572 2573 void virtio_notify_config(VirtIODevice *vdev) 2574 { 2575 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) 2576 return; 2577 2578 virtio_set_isr(vdev, 0x3); 2579 vdev->generation++; 2580 virtio_notify_vector(vdev, vdev->config_vector); 2581 } 2582 2583 static bool virtio_device_endian_needed(void *opaque) 2584 { 2585 VirtIODevice *vdev = opaque; 2586 2587 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN); 2588 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 2589 return vdev->device_endian != virtio_default_endian(); 2590 } 2591 /* Devices conforming to VIRTIO 1.0 or later are always LE. */ 2592 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE; 2593 } 2594 2595 static bool virtio_64bit_features_needed(void *opaque) 2596 { 2597 VirtIODevice *vdev = opaque; 2598 2599 return (vdev->host_features >> 32) != 0; 2600 } 2601 2602 static bool virtio_virtqueue_needed(void *opaque) 2603 { 2604 VirtIODevice *vdev = opaque; 2605 2606 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1); 2607 } 2608 2609 static bool virtio_packed_virtqueue_needed(void *opaque) 2610 { 2611 VirtIODevice *vdev = opaque; 2612 2613 return virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED); 2614 } 2615 2616 static bool virtio_ringsize_needed(void *opaque) 2617 { 2618 VirtIODevice *vdev = opaque; 2619 int i; 2620 2621 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2622 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) { 2623 return true; 2624 } 2625 } 2626 return false; 2627 } 2628 2629 static bool virtio_extra_state_needed(void *opaque) 2630 { 2631 VirtIODevice *vdev = opaque; 2632 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2633 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 2634 2635 return k->has_extra_state && 2636 k->has_extra_state(qbus->parent); 2637 } 2638 2639 static bool virtio_broken_needed(void *opaque) 2640 { 2641 VirtIODevice *vdev = opaque; 2642 2643 return vdev->broken; 2644 } 2645 2646 static bool virtio_started_needed(void *opaque) 2647 { 2648 VirtIODevice *vdev = opaque; 2649 2650 return vdev->started; 2651 } 2652 2653 static bool virtio_disabled_needed(void *opaque) 2654 { 2655 VirtIODevice *vdev = opaque; 2656 2657 return vdev->disabled; 2658 } 2659 2660 static const VMStateDescription vmstate_virtqueue = { 2661 .name = "virtqueue_state", 2662 .version_id = 1, 2663 .minimum_version_id = 1, 2664 .fields = (VMStateField[]) { 2665 VMSTATE_UINT64(vring.avail, struct VirtQueue), 2666 VMSTATE_UINT64(vring.used, struct VirtQueue), 2667 VMSTATE_END_OF_LIST() 2668 } 2669 }; 2670 2671 static const VMStateDescription vmstate_packed_virtqueue = { 2672 .name = "packed_virtqueue_state", 2673 .version_id = 1, 2674 .minimum_version_id = 1, 2675 .fields = (VMStateField[]) { 2676 VMSTATE_UINT16(last_avail_idx, struct VirtQueue), 2677 VMSTATE_BOOL(last_avail_wrap_counter, struct VirtQueue), 2678 VMSTATE_UINT16(used_idx, struct VirtQueue), 2679 VMSTATE_BOOL(used_wrap_counter, struct VirtQueue), 2680 VMSTATE_UINT32(inuse, struct VirtQueue), 2681 VMSTATE_END_OF_LIST() 2682 } 2683 }; 2684 2685 static const VMStateDescription vmstate_virtio_virtqueues = { 2686 .name = "virtio/virtqueues", 2687 .version_id = 1, 2688 .minimum_version_id = 1, 2689 .needed = &virtio_virtqueue_needed, 2690 .fields = (VMStateField[]) { 2691 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice, 2692 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue), 2693 VMSTATE_END_OF_LIST() 2694 } 2695 }; 2696 2697 static const VMStateDescription vmstate_virtio_packed_virtqueues = { 2698 .name = "virtio/packed_virtqueues", 2699 .version_id = 1, 2700 .minimum_version_id = 1, 2701 .needed = &virtio_packed_virtqueue_needed, 2702 .fields = (VMStateField[]) { 2703 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice, 2704 VIRTIO_QUEUE_MAX, 0, vmstate_packed_virtqueue, VirtQueue), 2705 VMSTATE_END_OF_LIST() 2706 } 2707 }; 2708 2709 static const VMStateDescription vmstate_ringsize = { 2710 .name = "ringsize_state", 2711 .version_id = 1, 2712 .minimum_version_id = 1, 2713 .fields = (VMStateField[]) { 2714 VMSTATE_UINT32(vring.num_default, struct VirtQueue), 2715 VMSTATE_END_OF_LIST() 2716 } 2717 }; 2718 2719 static const VMStateDescription vmstate_virtio_ringsize = { 2720 .name = "virtio/ringsize", 2721 .version_id = 1, 2722 .minimum_version_id = 1, 2723 .needed = &virtio_ringsize_needed, 2724 .fields = (VMStateField[]) { 2725 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice, 2726 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue), 2727 VMSTATE_END_OF_LIST() 2728 } 2729 }; 2730 2731 static int get_extra_state(QEMUFile *f, void *pv, size_t size, 2732 const VMStateField *field) 2733 { 2734 VirtIODevice *vdev = pv; 2735 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2736 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 2737 2738 if (!k->load_extra_state) { 2739 return -1; 2740 } else { 2741 return k->load_extra_state(qbus->parent, f); 2742 } 2743 } 2744 2745 static int put_extra_state(QEMUFile *f, void *pv, size_t size, 2746 const VMStateField *field, JSONWriter *vmdesc) 2747 { 2748 VirtIODevice *vdev = pv; 2749 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2750 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 2751 2752 k->save_extra_state(qbus->parent, f); 2753 return 0; 2754 } 2755 2756 static const VMStateInfo vmstate_info_extra_state = { 2757 .name = "virtqueue_extra_state", 2758 .get = get_extra_state, 2759 .put = put_extra_state, 2760 }; 2761 2762 static const VMStateDescription vmstate_virtio_extra_state = { 2763 .name = "virtio/extra_state", 2764 .version_id = 1, 2765 .minimum_version_id = 1, 2766 .needed = &virtio_extra_state_needed, 2767 .fields = (VMStateField[]) { 2768 { 2769 .name = "extra_state", 2770 .version_id = 0, 2771 .field_exists = NULL, 2772 .size = 0, 2773 .info = &vmstate_info_extra_state, 2774 .flags = VMS_SINGLE, 2775 .offset = 0, 2776 }, 2777 VMSTATE_END_OF_LIST() 2778 } 2779 }; 2780 2781 static const VMStateDescription vmstate_virtio_device_endian = { 2782 .name = "virtio/device_endian", 2783 .version_id = 1, 2784 .minimum_version_id = 1, 2785 .needed = &virtio_device_endian_needed, 2786 .fields = (VMStateField[]) { 2787 VMSTATE_UINT8(device_endian, VirtIODevice), 2788 VMSTATE_END_OF_LIST() 2789 } 2790 }; 2791 2792 static const VMStateDescription vmstate_virtio_64bit_features = { 2793 .name = "virtio/64bit_features", 2794 .version_id = 1, 2795 .minimum_version_id = 1, 2796 .needed = &virtio_64bit_features_needed, 2797 .fields = (VMStateField[]) { 2798 VMSTATE_UINT64(guest_features, VirtIODevice), 2799 VMSTATE_END_OF_LIST() 2800 } 2801 }; 2802 2803 static const VMStateDescription vmstate_virtio_broken = { 2804 .name = "virtio/broken", 2805 .version_id = 1, 2806 .minimum_version_id = 1, 2807 .needed = &virtio_broken_needed, 2808 .fields = (VMStateField[]) { 2809 VMSTATE_BOOL(broken, VirtIODevice), 2810 VMSTATE_END_OF_LIST() 2811 } 2812 }; 2813 2814 static const VMStateDescription vmstate_virtio_started = { 2815 .name = "virtio/started", 2816 .version_id = 1, 2817 .minimum_version_id = 1, 2818 .needed = &virtio_started_needed, 2819 .fields = (VMStateField[]) { 2820 VMSTATE_BOOL(started, VirtIODevice), 2821 VMSTATE_END_OF_LIST() 2822 } 2823 }; 2824 2825 static const VMStateDescription vmstate_virtio_disabled = { 2826 .name = "virtio/disabled", 2827 .version_id = 1, 2828 .minimum_version_id = 1, 2829 .needed = &virtio_disabled_needed, 2830 .fields = (VMStateField[]) { 2831 VMSTATE_BOOL(disabled, VirtIODevice), 2832 VMSTATE_END_OF_LIST() 2833 } 2834 }; 2835 2836 static const VMStateDescription vmstate_virtio = { 2837 .name = "virtio", 2838 .version_id = 1, 2839 .minimum_version_id = 1, 2840 .minimum_version_id_old = 1, 2841 .fields = (VMStateField[]) { 2842 VMSTATE_END_OF_LIST() 2843 }, 2844 .subsections = (const VMStateDescription*[]) { 2845 &vmstate_virtio_device_endian, 2846 &vmstate_virtio_64bit_features, 2847 &vmstate_virtio_virtqueues, 2848 &vmstate_virtio_ringsize, 2849 &vmstate_virtio_broken, 2850 &vmstate_virtio_extra_state, 2851 &vmstate_virtio_started, 2852 &vmstate_virtio_packed_virtqueues, 2853 &vmstate_virtio_disabled, 2854 NULL 2855 } 2856 }; 2857 2858 int virtio_save(VirtIODevice *vdev, QEMUFile *f) 2859 { 2860 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2861 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 2862 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); 2863 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff); 2864 int i; 2865 2866 if (k->save_config) { 2867 k->save_config(qbus->parent, f); 2868 } 2869 2870 qemu_put_8s(f, &vdev->status); 2871 qemu_put_8s(f, &vdev->isr); 2872 qemu_put_be16s(f, &vdev->queue_sel); 2873 qemu_put_be32s(f, &guest_features_lo); 2874 qemu_put_be32(f, vdev->config_len); 2875 qemu_put_buffer(f, vdev->config, vdev->config_len); 2876 2877 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2878 if (vdev->vq[i].vring.num == 0) 2879 break; 2880 } 2881 2882 qemu_put_be32(f, i); 2883 2884 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2885 if (vdev->vq[i].vring.num == 0) 2886 break; 2887 2888 qemu_put_be32(f, vdev->vq[i].vring.num); 2889 if (k->has_variable_vring_alignment) { 2890 qemu_put_be32(f, vdev->vq[i].vring.align); 2891 } 2892 /* 2893 * Save desc now, the rest of the ring addresses are saved in 2894 * subsections for VIRTIO-1 devices. 2895 */ 2896 qemu_put_be64(f, vdev->vq[i].vring.desc); 2897 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx); 2898 if (k->save_queue) { 2899 k->save_queue(qbus->parent, i, f); 2900 } 2901 } 2902 2903 if (vdc->save != NULL) { 2904 vdc->save(vdev, f); 2905 } 2906 2907 if (vdc->vmsd) { 2908 int ret = vmstate_save_state(f, vdc->vmsd, vdev, NULL); 2909 if (ret) { 2910 return ret; 2911 } 2912 } 2913 2914 /* Subsections */ 2915 return vmstate_save_state(f, &vmstate_virtio, vdev, NULL); 2916 } 2917 2918 /* A wrapper for use as a VMState .put function */ 2919 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size, 2920 const VMStateField *field, JSONWriter *vmdesc) 2921 { 2922 return virtio_save(VIRTIO_DEVICE(opaque), f); 2923 } 2924 2925 /* A wrapper for use as a VMState .get function */ 2926 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size, 2927 const VMStateField *field) 2928 { 2929 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 2930 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev)); 2931 2932 return virtio_load(vdev, f, dc->vmsd->version_id); 2933 } 2934 2935 const VMStateInfo virtio_vmstate_info = { 2936 .name = "virtio", 2937 .get = virtio_device_get, 2938 .put = virtio_device_put, 2939 }; 2940 2941 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val) 2942 { 2943 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 2944 bool bad = (val & ~(vdev->host_features)) != 0; 2945 2946 val &= vdev->host_features; 2947 if (k->set_features) { 2948 k->set_features(vdev, val); 2949 } 2950 vdev->guest_features = val; 2951 return bad ? -1 : 0; 2952 } 2953 2954 int virtio_set_features(VirtIODevice *vdev, uint64_t val) 2955 { 2956 int ret; 2957 /* 2958 * The driver must not attempt to set features after feature negotiation 2959 * has finished. 2960 */ 2961 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) { 2962 return -EINVAL; 2963 } 2964 ret = virtio_set_features_nocheck(vdev, val); 2965 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { 2966 /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */ 2967 int i; 2968 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2969 if (vdev->vq[i].vring.num != 0) { 2970 virtio_init_region_cache(vdev, i); 2971 } 2972 } 2973 } 2974 if (!ret) { 2975 if (!virtio_device_started(vdev, vdev->status) && 2976 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 2977 vdev->start_on_kick = true; 2978 } 2979 } 2980 return ret; 2981 } 2982 2983 size_t virtio_feature_get_config_size(const VirtIOFeature *feature_sizes, 2984 uint64_t host_features) 2985 { 2986 size_t config_size = 0; 2987 int i; 2988 2989 for (i = 0; feature_sizes[i].flags != 0; i++) { 2990 if (host_features & feature_sizes[i].flags) { 2991 config_size = MAX(feature_sizes[i].end, config_size); 2992 } 2993 } 2994 2995 return config_size; 2996 } 2997 2998 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) 2999 { 3000 int i, ret; 3001 int32_t config_len; 3002 uint32_t num; 3003 uint32_t features; 3004 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3005 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 3006 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); 3007 3008 /* 3009 * We poison the endianness to ensure it does not get used before 3010 * subsections have been loaded. 3011 */ 3012 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN; 3013 3014 if (k->load_config) { 3015 ret = k->load_config(qbus->parent, f); 3016 if (ret) 3017 return ret; 3018 } 3019 3020 qemu_get_8s(f, &vdev->status); 3021 qemu_get_8s(f, &vdev->isr); 3022 qemu_get_be16s(f, &vdev->queue_sel); 3023 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) { 3024 return -1; 3025 } 3026 qemu_get_be32s(f, &features); 3027 3028 /* 3029 * Temporarily set guest_features low bits - needed by 3030 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 3031 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ. 3032 * 3033 * Note: devices should always test host features in future - don't create 3034 * new dependencies like this. 3035 */ 3036 vdev->guest_features = features; 3037 3038 config_len = qemu_get_be32(f); 3039 3040 /* 3041 * There are cases where the incoming config can be bigger or smaller 3042 * than what we have; so load what we have space for, and skip 3043 * any excess that's in the stream. 3044 */ 3045 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len)); 3046 3047 while (config_len > vdev->config_len) { 3048 qemu_get_byte(f); 3049 config_len--; 3050 } 3051 3052 num = qemu_get_be32(f); 3053 3054 if (num > VIRTIO_QUEUE_MAX) { 3055 error_report("Invalid number of virtqueues: 0x%x", num); 3056 return -1; 3057 } 3058 3059 for (i = 0; i < num; i++) { 3060 vdev->vq[i].vring.num = qemu_get_be32(f); 3061 if (k->has_variable_vring_alignment) { 3062 vdev->vq[i].vring.align = qemu_get_be32(f); 3063 } 3064 vdev->vq[i].vring.desc = qemu_get_be64(f); 3065 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx); 3066 vdev->vq[i].signalled_used_valid = false; 3067 vdev->vq[i].notification = true; 3068 3069 if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) { 3070 error_report("VQ %d address 0x0 " 3071 "inconsistent with Host index 0x%x", 3072 i, vdev->vq[i].last_avail_idx); 3073 return -1; 3074 } 3075 if (k->load_queue) { 3076 ret = k->load_queue(qbus->parent, i, f); 3077 if (ret) 3078 return ret; 3079 } 3080 } 3081 3082 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); 3083 3084 if (vdc->load != NULL) { 3085 ret = vdc->load(vdev, f, version_id); 3086 if (ret) { 3087 return ret; 3088 } 3089 } 3090 3091 if (vdc->vmsd) { 3092 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id); 3093 if (ret) { 3094 return ret; 3095 } 3096 } 3097 3098 /* Subsections */ 3099 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1); 3100 if (ret) { 3101 return ret; 3102 } 3103 3104 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) { 3105 vdev->device_endian = virtio_default_endian(); 3106 } 3107 3108 if (virtio_64bit_features_needed(vdev)) { 3109 /* 3110 * Subsection load filled vdev->guest_features. Run them 3111 * through virtio_set_features to sanity-check them against 3112 * host_features. 3113 */ 3114 uint64_t features64 = vdev->guest_features; 3115 if (virtio_set_features_nocheck(vdev, features64) < 0) { 3116 error_report("Features 0x%" PRIx64 " unsupported. " 3117 "Allowed features: 0x%" PRIx64, 3118 features64, vdev->host_features); 3119 return -1; 3120 } 3121 } else { 3122 if (virtio_set_features_nocheck(vdev, features) < 0) { 3123 error_report("Features 0x%x unsupported. " 3124 "Allowed features: 0x%" PRIx64, 3125 features, vdev->host_features); 3126 return -1; 3127 } 3128 } 3129 3130 if (!virtio_device_started(vdev, vdev->status) && 3131 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 3132 vdev->start_on_kick = true; 3133 } 3134 3135 RCU_READ_LOCK_GUARD(); 3136 for (i = 0; i < num; i++) { 3137 if (vdev->vq[i].vring.desc) { 3138 uint16_t nheads; 3139 3140 /* 3141 * VIRTIO-1 devices migrate desc, used, and avail ring addresses so 3142 * only the region cache needs to be set up. Legacy devices need 3143 * to calculate used and avail ring addresses based on the desc 3144 * address. 3145 */ 3146 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 3147 virtio_init_region_cache(vdev, i); 3148 } else { 3149 virtio_queue_update_rings(vdev, i); 3150 } 3151 3152 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3153 vdev->vq[i].shadow_avail_idx = vdev->vq[i].last_avail_idx; 3154 vdev->vq[i].shadow_avail_wrap_counter = 3155 vdev->vq[i].last_avail_wrap_counter; 3156 continue; 3157 } 3158 3159 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx; 3160 /* Check it isn't doing strange things with descriptor numbers. */ 3161 if (nheads > vdev->vq[i].vring.num) { 3162 virtio_error(vdev, "VQ %d size 0x%x Guest index 0x%x " 3163 "inconsistent with Host index 0x%x: delta 0x%x", 3164 i, vdev->vq[i].vring.num, 3165 vring_avail_idx(&vdev->vq[i]), 3166 vdev->vq[i].last_avail_idx, nheads); 3167 vdev->vq[i].used_idx = 0; 3168 vdev->vq[i].shadow_avail_idx = 0; 3169 vdev->vq[i].inuse = 0; 3170 continue; 3171 } 3172 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]); 3173 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]); 3174 3175 /* 3176 * Some devices migrate VirtQueueElements that have been popped 3177 * from the avail ring but not yet returned to the used ring. 3178 * Since max ring size < UINT16_MAX it's safe to use modulo 3179 * UINT16_MAX + 1 subtraction. 3180 */ 3181 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx - 3182 vdev->vq[i].used_idx); 3183 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) { 3184 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - " 3185 "used_idx 0x%x", 3186 i, vdev->vq[i].vring.num, 3187 vdev->vq[i].last_avail_idx, 3188 vdev->vq[i].used_idx); 3189 return -1; 3190 } 3191 } 3192 } 3193 3194 if (vdc->post_load) { 3195 ret = vdc->post_load(vdev); 3196 if (ret) { 3197 return ret; 3198 } 3199 } 3200 3201 return 0; 3202 } 3203 3204 void virtio_cleanup(VirtIODevice *vdev) 3205 { 3206 qemu_del_vm_change_state_handler(vdev->vmstate); 3207 } 3208 3209 static void virtio_vmstate_change(void *opaque, bool running, RunState state) 3210 { 3211 VirtIODevice *vdev = opaque; 3212 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3213 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 3214 bool backend_run = running && virtio_device_started(vdev, vdev->status); 3215 vdev->vm_running = running; 3216 3217 if (backend_run) { 3218 virtio_set_status(vdev, vdev->status); 3219 } 3220 3221 if (k->vmstate_change) { 3222 k->vmstate_change(qbus->parent, backend_run); 3223 } 3224 3225 if (!backend_run) { 3226 virtio_set_status(vdev, vdev->status); 3227 } 3228 } 3229 3230 void virtio_instance_init_common(Object *proxy_obj, void *data, 3231 size_t vdev_size, const char *vdev_name) 3232 { 3233 DeviceState *vdev = data; 3234 3235 object_initialize_child_with_props(proxy_obj, "virtio-backend", vdev, 3236 vdev_size, vdev_name, &error_abort, 3237 NULL); 3238 qdev_alias_all_properties(vdev, proxy_obj); 3239 } 3240 3241 void virtio_init(VirtIODevice *vdev, const char *name, 3242 uint16_t device_id, size_t config_size) 3243 { 3244 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3245 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 3246 int i; 3247 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0; 3248 3249 if (nvectors) { 3250 vdev->vector_queues = 3251 g_malloc0(sizeof(*vdev->vector_queues) * nvectors); 3252 } 3253 3254 vdev->start_on_kick = false; 3255 vdev->started = false; 3256 vdev->device_id = device_id; 3257 vdev->status = 0; 3258 qatomic_set(&vdev->isr, 0); 3259 vdev->queue_sel = 0; 3260 vdev->config_vector = VIRTIO_NO_VECTOR; 3261 vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX); 3262 vdev->vm_running = runstate_is_running(); 3263 vdev->broken = false; 3264 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 3265 vdev->vq[i].vector = VIRTIO_NO_VECTOR; 3266 vdev->vq[i].vdev = vdev; 3267 vdev->vq[i].queue_index = i; 3268 vdev->vq[i].host_notifier_enabled = false; 3269 } 3270 3271 vdev->name = name; 3272 vdev->config_len = config_size; 3273 if (vdev->config_len) { 3274 vdev->config = g_malloc0(config_size); 3275 } else { 3276 vdev->config = NULL; 3277 } 3278 vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev), 3279 virtio_vmstate_change, vdev); 3280 vdev->device_endian = virtio_default_endian(); 3281 vdev->use_guest_notifier_mask = true; 3282 } 3283 3284 /* 3285 * Only devices that have already been around prior to defining the virtio 3286 * standard support legacy mode; this includes devices not specified in the 3287 * standard. All newer devices conform to the virtio standard only. 3288 */ 3289 bool virtio_legacy_allowed(VirtIODevice *vdev) 3290 { 3291 switch (vdev->device_id) { 3292 case VIRTIO_ID_NET: 3293 case VIRTIO_ID_BLOCK: 3294 case VIRTIO_ID_CONSOLE: 3295 case VIRTIO_ID_RNG: 3296 case VIRTIO_ID_BALLOON: 3297 case VIRTIO_ID_RPMSG: 3298 case VIRTIO_ID_SCSI: 3299 case VIRTIO_ID_9P: 3300 case VIRTIO_ID_RPROC_SERIAL: 3301 case VIRTIO_ID_CAIF: 3302 return true; 3303 default: 3304 return false; 3305 } 3306 } 3307 3308 bool virtio_legacy_check_disabled(VirtIODevice *vdev) 3309 { 3310 return vdev->disable_legacy_check; 3311 } 3312 3313 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) 3314 { 3315 return vdev->vq[n].vring.desc; 3316 } 3317 3318 bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n) 3319 { 3320 return virtio_queue_get_desc_addr(vdev, n) != 0; 3321 } 3322 3323 bool virtio_queue_enabled(VirtIODevice *vdev, int n) 3324 { 3325 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3326 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 3327 3328 if (k->queue_enabled) { 3329 return k->queue_enabled(qbus->parent, n); 3330 } 3331 return virtio_queue_enabled_legacy(vdev, n); 3332 } 3333 3334 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n) 3335 { 3336 return vdev->vq[n].vring.avail; 3337 } 3338 3339 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n) 3340 { 3341 return vdev->vq[n].vring.used; 3342 } 3343 3344 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n) 3345 { 3346 return sizeof(VRingDesc) * vdev->vq[n].vring.num; 3347 } 3348 3349 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n) 3350 { 3351 int s; 3352 3353 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3354 return sizeof(struct VRingPackedDescEvent); 3355 } 3356 3357 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 3358 return offsetof(VRingAvail, ring) + 3359 sizeof(uint16_t) * vdev->vq[n].vring.num + s; 3360 } 3361 3362 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n) 3363 { 3364 int s; 3365 3366 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3367 return sizeof(struct VRingPackedDescEvent); 3368 } 3369 3370 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 3371 return offsetof(VRingUsed, ring) + 3372 sizeof(VRingUsedElem) * vdev->vq[n].vring.num + s; 3373 } 3374 3375 static unsigned int virtio_queue_packed_get_last_avail_idx(VirtIODevice *vdev, 3376 int n) 3377 { 3378 unsigned int avail, used; 3379 3380 avail = vdev->vq[n].last_avail_idx; 3381 avail |= ((uint16_t)vdev->vq[n].last_avail_wrap_counter) << 15; 3382 3383 used = vdev->vq[n].used_idx; 3384 used |= ((uint16_t)vdev->vq[n].used_wrap_counter) << 15; 3385 3386 return avail | used << 16; 3387 } 3388 3389 static uint16_t virtio_queue_split_get_last_avail_idx(VirtIODevice *vdev, 3390 int n) 3391 { 3392 return vdev->vq[n].last_avail_idx; 3393 } 3394 3395 unsigned int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n) 3396 { 3397 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3398 return virtio_queue_packed_get_last_avail_idx(vdev, n); 3399 } else { 3400 return virtio_queue_split_get_last_avail_idx(vdev, n); 3401 } 3402 } 3403 3404 static void virtio_queue_packed_set_last_avail_idx(VirtIODevice *vdev, 3405 int n, unsigned int idx) 3406 { 3407 struct VirtQueue *vq = &vdev->vq[n]; 3408 3409 vq->last_avail_idx = vq->shadow_avail_idx = idx & 0x7fff; 3410 vq->last_avail_wrap_counter = 3411 vq->shadow_avail_wrap_counter = !!(idx & 0x8000); 3412 idx >>= 16; 3413 vq->used_idx = idx & 0x7ffff; 3414 vq->used_wrap_counter = !!(idx & 0x8000); 3415 } 3416 3417 static void virtio_queue_split_set_last_avail_idx(VirtIODevice *vdev, 3418 int n, unsigned int idx) 3419 { 3420 vdev->vq[n].last_avail_idx = idx; 3421 vdev->vq[n].shadow_avail_idx = idx; 3422 } 3423 3424 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, 3425 unsigned int idx) 3426 { 3427 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3428 virtio_queue_packed_set_last_avail_idx(vdev, n, idx); 3429 } else { 3430 virtio_queue_split_set_last_avail_idx(vdev, n, idx); 3431 } 3432 } 3433 3434 static void virtio_queue_packed_restore_last_avail_idx(VirtIODevice *vdev, 3435 int n) 3436 { 3437 /* We don't have a reference like avail idx in shared memory */ 3438 return; 3439 } 3440 3441 static void virtio_queue_split_restore_last_avail_idx(VirtIODevice *vdev, 3442 int n) 3443 { 3444 RCU_READ_LOCK_GUARD(); 3445 if (vdev->vq[n].vring.desc) { 3446 vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]); 3447 vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx; 3448 } 3449 } 3450 3451 void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n) 3452 { 3453 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3454 virtio_queue_packed_restore_last_avail_idx(vdev, n); 3455 } else { 3456 virtio_queue_split_restore_last_avail_idx(vdev, n); 3457 } 3458 } 3459 3460 static void virtio_queue_packed_update_used_idx(VirtIODevice *vdev, int n) 3461 { 3462 /* used idx was updated through set_last_avail_idx() */ 3463 return; 3464 } 3465 3466 static void virtio_split_packed_update_used_idx(VirtIODevice *vdev, int n) 3467 { 3468 RCU_READ_LOCK_GUARD(); 3469 if (vdev->vq[n].vring.desc) { 3470 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]); 3471 } 3472 } 3473 3474 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) 3475 { 3476 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) { 3477 return virtio_queue_packed_update_used_idx(vdev, n); 3478 } else { 3479 return virtio_split_packed_update_used_idx(vdev, n); 3480 } 3481 } 3482 3483 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n) 3484 { 3485 vdev->vq[n].signalled_used_valid = false; 3486 } 3487 3488 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n) 3489 { 3490 return vdev->vq + n; 3491 } 3492 3493 uint16_t virtio_get_queue_index(VirtQueue *vq) 3494 { 3495 return vq->queue_index; 3496 } 3497 3498 static void virtio_queue_guest_notifier_read(EventNotifier *n) 3499 { 3500 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier); 3501 if (event_notifier_test_and_clear(n)) { 3502 virtio_irq(vq); 3503 } 3504 } 3505 3506 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign, 3507 bool with_irqfd) 3508 { 3509 if (assign && !with_irqfd) { 3510 event_notifier_set_handler(&vq->guest_notifier, 3511 virtio_queue_guest_notifier_read); 3512 } else { 3513 event_notifier_set_handler(&vq->guest_notifier, NULL); 3514 } 3515 if (!assign) { 3516 /* Test and clear notifier before closing it, 3517 * in case poll callback didn't have time to run. */ 3518 virtio_queue_guest_notifier_read(&vq->guest_notifier); 3519 } 3520 } 3521 3522 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq) 3523 { 3524 return &vq->guest_notifier; 3525 } 3526 3527 static void virtio_queue_host_notifier_aio_read(EventNotifier *n) 3528 { 3529 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 3530 if (event_notifier_test_and_clear(n)) { 3531 virtio_queue_notify_aio_vq(vq); 3532 } 3533 } 3534 3535 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n) 3536 { 3537 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 3538 3539 virtio_queue_set_notification(vq, 0); 3540 } 3541 3542 static bool virtio_queue_host_notifier_aio_poll(void *opaque) 3543 { 3544 EventNotifier *n = opaque; 3545 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 3546 3547 if (!vq->vring.desc || virtio_queue_empty(vq)) { 3548 return false; 3549 } 3550 3551 return virtio_queue_notify_aio_vq(vq); 3552 } 3553 3554 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n) 3555 { 3556 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 3557 3558 /* Caller polls once more after this to catch requests that race with us */ 3559 virtio_queue_set_notification(vq, 1); 3560 } 3561 3562 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx, 3563 VirtIOHandleAIOOutput handle_output) 3564 { 3565 if (handle_output) { 3566 vq->handle_aio_output = handle_output; 3567 aio_set_event_notifier(ctx, &vq->host_notifier, true, 3568 virtio_queue_host_notifier_aio_read, 3569 virtio_queue_host_notifier_aio_poll); 3570 aio_set_event_notifier_poll(ctx, &vq->host_notifier, 3571 virtio_queue_host_notifier_aio_poll_begin, 3572 virtio_queue_host_notifier_aio_poll_end); 3573 } else { 3574 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL); 3575 /* Test and clear notifier before after disabling event, 3576 * in case poll callback didn't have time to run. */ 3577 virtio_queue_host_notifier_aio_read(&vq->host_notifier); 3578 vq->handle_aio_output = NULL; 3579 } 3580 } 3581 3582 void virtio_queue_host_notifier_read(EventNotifier *n) 3583 { 3584 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 3585 if (event_notifier_test_and_clear(n)) { 3586 virtio_queue_notify_vq(vq); 3587 } 3588 } 3589 3590 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq) 3591 { 3592 return &vq->host_notifier; 3593 } 3594 3595 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled) 3596 { 3597 vq->host_notifier_enabled = enabled; 3598 } 3599 3600 int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, int n, 3601 MemoryRegion *mr, bool assign) 3602 { 3603 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3604 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 3605 3606 if (k->set_host_notifier_mr) { 3607 return k->set_host_notifier_mr(qbus->parent, n, mr, assign); 3608 } 3609 3610 return -1; 3611 } 3612 3613 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name) 3614 { 3615 g_free(vdev->bus_name); 3616 vdev->bus_name = g_strdup(bus_name); 3617 } 3618 3619 void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...) 3620 { 3621 va_list ap; 3622 3623 va_start(ap, fmt); 3624 error_vreport(fmt, ap); 3625 va_end(ap); 3626 3627 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 3628 vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET; 3629 virtio_notify_config(vdev); 3630 } 3631 3632 vdev->broken = true; 3633 } 3634 3635 static void virtio_memory_listener_commit(MemoryListener *listener) 3636 { 3637 VirtIODevice *vdev = container_of(listener, VirtIODevice, listener); 3638 int i; 3639 3640 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 3641 if (vdev->vq[i].vring.num == 0) { 3642 break; 3643 } 3644 virtio_init_region_cache(vdev, i); 3645 } 3646 } 3647 3648 static void virtio_device_realize(DeviceState *dev, Error **errp) 3649 { 3650 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 3651 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev); 3652 Error *err = NULL; 3653 3654 /* Devices should either use vmsd or the load/save methods */ 3655 assert(!vdc->vmsd || !vdc->load); 3656 3657 if (vdc->realize != NULL) { 3658 vdc->realize(dev, &err); 3659 if (err != NULL) { 3660 error_propagate(errp, err); 3661 return; 3662 } 3663 } 3664 3665 virtio_bus_device_plugged(vdev, &err); 3666 if (err != NULL) { 3667 error_propagate(errp, err); 3668 vdc->unrealize(dev); 3669 return; 3670 } 3671 3672 vdev->listener.commit = virtio_memory_listener_commit; 3673 vdev->listener.name = "virtio"; 3674 memory_listener_register(&vdev->listener, vdev->dma_as); 3675 } 3676 3677 static void virtio_device_unrealize(DeviceState *dev) 3678 { 3679 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 3680 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev); 3681 3682 memory_listener_unregister(&vdev->listener); 3683 virtio_bus_device_unplugged(vdev); 3684 3685 if (vdc->unrealize != NULL) { 3686 vdc->unrealize(dev); 3687 } 3688 3689 g_free(vdev->bus_name); 3690 vdev->bus_name = NULL; 3691 } 3692 3693 static void virtio_device_free_virtqueues(VirtIODevice *vdev) 3694 { 3695 int i; 3696 if (!vdev->vq) { 3697 return; 3698 } 3699 3700 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 3701 if (vdev->vq[i].vring.num == 0) { 3702 break; 3703 } 3704 virtio_virtqueue_reset_region_cache(&vdev->vq[i]); 3705 } 3706 g_free(vdev->vq); 3707 } 3708 3709 static void virtio_device_instance_finalize(Object *obj) 3710 { 3711 VirtIODevice *vdev = VIRTIO_DEVICE(obj); 3712 3713 virtio_device_free_virtqueues(vdev); 3714 3715 g_free(vdev->config); 3716 g_free(vdev->vector_queues); 3717 } 3718 3719 static Property virtio_properties[] = { 3720 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features), 3721 DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true), 3722 DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true), 3723 DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice, 3724 disable_legacy_check, false), 3725 DEFINE_PROP_END_OF_LIST(), 3726 }; 3727 3728 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) 3729 { 3730 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); 3731 int i, n, r, err; 3732 3733 /* 3734 * Batch all the host notifiers in a single transaction to avoid 3735 * quadratic time complexity in address_space_update_ioeventfds(). 3736 */ 3737 memory_region_transaction_begin(); 3738 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 3739 VirtQueue *vq = &vdev->vq[n]; 3740 if (!virtio_queue_get_num(vdev, n)) { 3741 continue; 3742 } 3743 r = virtio_bus_set_host_notifier(qbus, n, true); 3744 if (r < 0) { 3745 err = r; 3746 goto assign_error; 3747 } 3748 event_notifier_set_handler(&vq->host_notifier, 3749 virtio_queue_host_notifier_read); 3750 } 3751 3752 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 3753 /* Kick right away to begin processing requests already in vring */ 3754 VirtQueue *vq = &vdev->vq[n]; 3755 if (!vq->vring.num) { 3756 continue; 3757 } 3758 event_notifier_set(&vq->host_notifier); 3759 } 3760 memory_region_transaction_commit(); 3761 return 0; 3762 3763 assign_error: 3764 i = n; /* save n for a second iteration after transaction is committed. */ 3765 while (--n >= 0) { 3766 VirtQueue *vq = &vdev->vq[n]; 3767 if (!virtio_queue_get_num(vdev, n)) { 3768 continue; 3769 } 3770 3771 event_notifier_set_handler(&vq->host_notifier, NULL); 3772 r = virtio_bus_set_host_notifier(qbus, n, false); 3773 assert(r >= 0); 3774 } 3775 /* 3776 * The transaction expects the ioeventfds to be open when it 3777 * commits. Do it now, before the cleanup loop. 3778 */ 3779 memory_region_transaction_commit(); 3780 3781 while (--i >= 0) { 3782 if (!virtio_queue_get_num(vdev, i)) { 3783 continue; 3784 } 3785 virtio_bus_cleanup_host_notifier(qbus, i); 3786 } 3787 return err; 3788 } 3789 3790 int virtio_device_start_ioeventfd(VirtIODevice *vdev) 3791 { 3792 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3793 VirtioBusState *vbus = VIRTIO_BUS(qbus); 3794 3795 return virtio_bus_start_ioeventfd(vbus); 3796 } 3797 3798 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) 3799 { 3800 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); 3801 int n, r; 3802 3803 /* 3804 * Batch all the host notifiers in a single transaction to avoid 3805 * quadratic time complexity in address_space_update_ioeventfds(). 3806 */ 3807 memory_region_transaction_begin(); 3808 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 3809 VirtQueue *vq = &vdev->vq[n]; 3810 3811 if (!virtio_queue_get_num(vdev, n)) { 3812 continue; 3813 } 3814 event_notifier_set_handler(&vq->host_notifier, NULL); 3815 r = virtio_bus_set_host_notifier(qbus, n, false); 3816 assert(r >= 0); 3817 } 3818 /* 3819 * The transaction expects the ioeventfds to be open when it 3820 * commits. Do it now, before the cleanup loop. 3821 */ 3822 memory_region_transaction_commit(); 3823 3824 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 3825 if (!virtio_queue_get_num(vdev, n)) { 3826 continue; 3827 } 3828 virtio_bus_cleanup_host_notifier(qbus, n); 3829 } 3830 } 3831 3832 int virtio_device_grab_ioeventfd(VirtIODevice *vdev) 3833 { 3834 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3835 VirtioBusState *vbus = VIRTIO_BUS(qbus); 3836 3837 return virtio_bus_grab_ioeventfd(vbus); 3838 } 3839 3840 void virtio_device_release_ioeventfd(VirtIODevice *vdev) 3841 { 3842 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3843 VirtioBusState *vbus = VIRTIO_BUS(qbus); 3844 3845 virtio_bus_release_ioeventfd(vbus); 3846 } 3847 3848 static void virtio_device_class_init(ObjectClass *klass, void *data) 3849 { 3850 /* Set the default value here. */ 3851 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 3852 DeviceClass *dc = DEVICE_CLASS(klass); 3853 3854 dc->realize = virtio_device_realize; 3855 dc->unrealize = virtio_device_unrealize; 3856 dc->bus_type = TYPE_VIRTIO_BUS; 3857 device_class_set_props(dc, virtio_properties); 3858 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl; 3859 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl; 3860 3861 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES; 3862 } 3863 3864 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev) 3865 { 3866 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 3867 VirtioBusState *vbus = VIRTIO_BUS(qbus); 3868 3869 return virtio_bus_ioeventfd_enabled(vbus); 3870 } 3871 3872 static const TypeInfo virtio_device_info = { 3873 .name = TYPE_VIRTIO_DEVICE, 3874 .parent = TYPE_DEVICE, 3875 .instance_size = sizeof(VirtIODevice), 3876 .class_init = virtio_device_class_init, 3877 .instance_finalize = virtio_device_instance_finalize, 3878 .abstract = true, 3879 .class_size = sizeof(VirtioDeviceClass), 3880 }; 3881 3882 static void virtio_register_types(void) 3883 { 3884 type_register_static(&virtio_device_info); 3885 } 3886 3887 type_init(virtio_register_types) 3888