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