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