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