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 "qemu-common.h" 17 #include "cpu.h" 18 #include "trace.h" 19 #include "exec/address-spaces.h" 20 #include "qemu/error-report.h" 21 #include "hw/virtio/virtio.h" 22 #include "qemu/atomic.h" 23 #include "hw/virtio/virtio-bus.h" 24 #include "migration/migration.h" 25 #include "hw/virtio/virtio-access.h" 26 #include "sysemu/dma.h" 27 28 /* 29 * The alignment to use between consumer and producer parts of vring. 30 * x86 pagesize again. This is the default, used by transports like PCI 31 * which don't provide a means for the guest to tell the host the alignment. 32 */ 33 #define VIRTIO_PCI_VRING_ALIGN 4096 34 35 typedef struct VRingDesc 36 { 37 uint64_t addr; 38 uint32_t len; 39 uint16_t flags; 40 uint16_t next; 41 } VRingDesc; 42 43 typedef struct VRingAvail 44 { 45 uint16_t flags; 46 uint16_t idx; 47 uint16_t ring[0]; 48 } VRingAvail; 49 50 typedef struct VRingUsedElem 51 { 52 uint32_t id; 53 uint32_t len; 54 } VRingUsedElem; 55 56 typedef struct VRingUsed 57 { 58 uint16_t flags; 59 uint16_t idx; 60 VRingUsedElem ring[0]; 61 } VRingUsed; 62 63 typedef struct VRing 64 { 65 unsigned int num; 66 unsigned int num_default; 67 unsigned int align; 68 hwaddr desc; 69 hwaddr avail; 70 hwaddr used; 71 } VRing; 72 73 struct VirtQueue 74 { 75 VRing vring; 76 77 /* Next head to pop */ 78 uint16_t last_avail_idx; 79 80 /* Last avail_idx read from VQ. */ 81 uint16_t shadow_avail_idx; 82 83 uint16_t used_idx; 84 85 /* Last used index value we have signalled on */ 86 uint16_t signalled_used; 87 88 /* Last used index value we have signalled on */ 89 bool signalled_used_valid; 90 91 /* Nested host->guest notification disabled counter */ 92 unsigned int notification_disabled; 93 94 uint16_t queue_index; 95 96 unsigned int inuse; 97 98 uint16_t vector; 99 VirtIOHandleOutput handle_output; 100 VirtIOHandleOutput handle_aio_output; 101 VirtIODevice *vdev; 102 EventNotifier guest_notifier; 103 EventNotifier host_notifier; 104 QLIST_ENTRY(VirtQueue) node; 105 }; 106 107 /* virt queue functions */ 108 void virtio_queue_update_rings(VirtIODevice *vdev, int n) 109 { 110 VRing *vring = &vdev->vq[n].vring; 111 112 if (!vring->desc) { 113 /* not yet setup -> nothing to do */ 114 return; 115 } 116 vring->avail = vring->desc + vring->num * sizeof(VRingDesc); 117 vring->used = vring_align(vring->avail + 118 offsetof(VRingAvail, ring[vring->num]), 119 vring->align); 120 } 121 122 static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc, 123 hwaddr desc_pa, int i) 124 { 125 address_space_read(vdev->dma_as, desc_pa + i * sizeof(VRingDesc), 126 MEMTXATTRS_UNSPECIFIED, (void *)desc, sizeof(VRingDesc)); 127 virtio_tswap64s(vdev, &desc->addr); 128 virtio_tswap32s(vdev, &desc->len); 129 virtio_tswap16s(vdev, &desc->flags); 130 virtio_tswap16s(vdev, &desc->next); 131 } 132 133 static inline uint16_t vring_avail_flags(VirtQueue *vq) 134 { 135 hwaddr pa; 136 pa = vq->vring.avail + offsetof(VRingAvail, flags); 137 return virtio_lduw_phys(vq->vdev, pa); 138 } 139 140 static inline uint16_t vring_avail_idx(VirtQueue *vq) 141 { 142 hwaddr pa; 143 pa = vq->vring.avail + offsetof(VRingAvail, idx); 144 vq->shadow_avail_idx = virtio_lduw_phys(vq->vdev, pa); 145 return vq->shadow_avail_idx; 146 } 147 148 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i) 149 { 150 hwaddr pa; 151 pa = vq->vring.avail + offsetof(VRingAvail, ring[i]); 152 return virtio_lduw_phys(vq->vdev, pa); 153 } 154 155 static inline uint16_t vring_get_used_event(VirtQueue *vq) 156 { 157 return vring_avail_ring(vq, vq->vring.num); 158 } 159 160 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem, 161 int i) 162 { 163 hwaddr pa; 164 virtio_tswap32s(vq->vdev, &uelem->id); 165 virtio_tswap32s(vq->vdev, &uelem->len); 166 pa = vq->vring.used + offsetof(VRingUsed, ring[i]); 167 address_space_write(vq->vdev->dma_as, pa, MEMTXATTRS_UNSPECIFIED, 168 (void *)uelem, sizeof(VRingUsedElem)); 169 } 170 171 static uint16_t vring_used_idx(VirtQueue *vq) 172 { 173 hwaddr pa; 174 pa = vq->vring.used + offsetof(VRingUsed, idx); 175 return virtio_lduw_phys(vq->vdev, pa); 176 } 177 178 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val) 179 { 180 hwaddr pa; 181 pa = vq->vring.used + offsetof(VRingUsed, idx); 182 virtio_stw_phys(vq->vdev, pa, val); 183 vq->used_idx = val; 184 } 185 186 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask) 187 { 188 VirtIODevice *vdev = vq->vdev; 189 hwaddr pa; 190 pa = vq->vring.used + offsetof(VRingUsed, flags); 191 virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) | mask); 192 } 193 194 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask) 195 { 196 VirtIODevice *vdev = vq->vdev; 197 hwaddr pa; 198 pa = vq->vring.used + offsetof(VRingUsed, flags); 199 virtio_stw_phys(vdev, pa, virtio_lduw_phys(vdev, pa) & ~mask); 200 } 201 202 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val) 203 { 204 hwaddr pa; 205 if (vq->notification_disabled) { 206 return; 207 } 208 pa = vq->vring.used + offsetof(VRingUsed, ring[vq->vring.num]); 209 virtio_stw_phys(vq->vdev, pa, val); 210 } 211 212 void virtio_queue_set_notification(VirtQueue *vq, int enable) 213 { 214 if (enable) { 215 assert(vq->notification_disabled > 0); 216 vq->notification_disabled--; 217 } else { 218 vq->notification_disabled++; 219 } 220 221 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) { 222 vring_set_avail_event(vq, vring_avail_idx(vq)); 223 } else if (enable) { 224 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY); 225 } else { 226 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY); 227 } 228 if (enable) { 229 /* Expose avail event/used flags before caller checks the avail idx. */ 230 smp_mb(); 231 } 232 } 233 234 int virtio_queue_ready(VirtQueue *vq) 235 { 236 return vq->vring.avail != 0; 237 } 238 239 /* Fetch avail_idx from VQ memory only when we really need to know if 240 * guest has added some buffers. */ 241 int virtio_queue_empty(VirtQueue *vq) 242 { 243 if (vq->shadow_avail_idx != vq->last_avail_idx) { 244 return 0; 245 } 246 247 return vring_avail_idx(vq) == vq->last_avail_idx; 248 } 249 250 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem, 251 unsigned int len) 252 { 253 AddressSpace *dma_as = vq->vdev->dma_as; 254 unsigned int offset; 255 int i; 256 257 offset = 0; 258 for (i = 0; i < elem->in_num; i++) { 259 size_t size = MIN(len - offset, elem->in_sg[i].iov_len); 260 261 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base, 262 elem->in_sg[i].iov_len, 263 DMA_DIRECTION_FROM_DEVICE, size); 264 265 offset += size; 266 } 267 268 for (i = 0; i < elem->out_num; i++) 269 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base, 270 elem->out_sg[i].iov_len, 271 DMA_DIRECTION_TO_DEVICE, 272 elem->out_sg[i].iov_len); 273 } 274 275 /* virtqueue_detach_element: 276 * @vq: The #VirtQueue 277 * @elem: The #VirtQueueElement 278 * @len: number of bytes written 279 * 280 * Detach the element from the virtqueue. This function is suitable for device 281 * reset or other situations where a #VirtQueueElement is simply freed and will 282 * not be pushed or discarded. 283 */ 284 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem, 285 unsigned int len) 286 { 287 vq->inuse--; 288 virtqueue_unmap_sg(vq, elem, len); 289 } 290 291 /* virtqueue_unpop: 292 * @vq: The #VirtQueue 293 * @elem: The #VirtQueueElement 294 * @len: number of bytes written 295 * 296 * Pretend the most recent element wasn't popped from the virtqueue. The next 297 * call to virtqueue_pop() will refetch the element. 298 */ 299 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem, 300 unsigned int len) 301 { 302 vq->last_avail_idx--; 303 virtqueue_detach_element(vq, elem, len); 304 } 305 306 /* virtqueue_rewind: 307 * @vq: The #VirtQueue 308 * @num: Number of elements to push back 309 * 310 * Pretend that elements weren't popped from the virtqueue. The next 311 * virtqueue_pop() will refetch the oldest element. 312 * 313 * Use virtqueue_unpop() instead if you have a VirtQueueElement. 314 * 315 * Returns: true on success, false if @num is greater than the number of in use 316 * elements. 317 */ 318 bool virtqueue_rewind(VirtQueue *vq, unsigned int num) 319 { 320 if (num > vq->inuse) { 321 return false; 322 } 323 vq->last_avail_idx -= num; 324 vq->inuse -= num; 325 return true; 326 } 327 328 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem, 329 unsigned int len, unsigned int idx) 330 { 331 VRingUsedElem uelem; 332 333 trace_virtqueue_fill(vq, elem, len, idx); 334 335 virtqueue_unmap_sg(vq, elem, len); 336 337 if (unlikely(vq->vdev->broken)) { 338 return; 339 } 340 341 idx = (idx + vq->used_idx) % vq->vring.num; 342 343 uelem.id = elem->index; 344 uelem.len = len; 345 vring_used_write(vq, &uelem, idx); 346 } 347 348 void virtqueue_flush(VirtQueue *vq, unsigned int count) 349 { 350 uint16_t old, new; 351 352 if (unlikely(vq->vdev->broken)) { 353 vq->inuse -= count; 354 return; 355 } 356 357 /* Make sure buffer is written before we update index. */ 358 smp_wmb(); 359 trace_virtqueue_flush(vq, count); 360 old = vq->used_idx; 361 new = old + count; 362 vring_used_idx_set(vq, new); 363 vq->inuse -= count; 364 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) 365 vq->signalled_used_valid = false; 366 } 367 368 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem, 369 unsigned int len) 370 { 371 virtqueue_fill(vq, elem, len, 0); 372 virtqueue_flush(vq, 1); 373 } 374 375 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx) 376 { 377 uint16_t num_heads = vring_avail_idx(vq) - idx; 378 379 /* Check it isn't doing very strange things with descriptor numbers. */ 380 if (num_heads > vq->vring.num) { 381 virtio_error(vq->vdev, "Guest moved used index from %u to %u", 382 idx, vq->shadow_avail_idx); 383 return -EINVAL; 384 } 385 /* On success, callers read a descriptor at vq->last_avail_idx. 386 * Make sure descriptor read does not bypass avail index read. */ 387 if (num_heads) { 388 smp_rmb(); 389 } 390 391 return num_heads; 392 } 393 394 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx, 395 unsigned int *head) 396 { 397 /* Grab the next descriptor number they're advertising, and increment 398 * the index we've seen. */ 399 *head = vring_avail_ring(vq, idx % vq->vring.num); 400 401 /* If their number is silly, that's a fatal mistake. */ 402 if (*head >= vq->vring.num) { 403 virtio_error(vq->vdev, "Guest says index %u is available", *head); 404 return false; 405 } 406 407 return true; 408 } 409 410 enum { 411 VIRTQUEUE_READ_DESC_ERROR = -1, 412 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */ 413 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */ 414 }; 415 416 static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc, 417 hwaddr desc_pa, unsigned int max, 418 unsigned int *next) 419 { 420 /* If this descriptor says it doesn't chain, we're done. */ 421 if (!(desc->flags & VRING_DESC_F_NEXT)) { 422 return VIRTQUEUE_READ_DESC_DONE; 423 } 424 425 /* Check they're not leading us off end of descriptors. */ 426 *next = desc->next; 427 /* Make sure compiler knows to grab that: we don't want it changing! */ 428 smp_wmb(); 429 430 if (*next >= max) { 431 virtio_error(vdev, "Desc next is %u", *next); 432 return VIRTQUEUE_READ_DESC_ERROR; 433 } 434 435 vring_desc_read(vdev, desc, desc_pa, *next); 436 return VIRTQUEUE_READ_DESC_MORE; 437 } 438 439 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes, 440 unsigned int *out_bytes, 441 unsigned max_in_bytes, unsigned max_out_bytes) 442 { 443 unsigned int idx; 444 unsigned int total_bufs, in_total, out_total; 445 int rc; 446 447 idx = vq->last_avail_idx; 448 449 total_bufs = in_total = out_total = 0; 450 while ((rc = virtqueue_num_heads(vq, idx)) > 0) { 451 VirtIODevice *vdev = vq->vdev; 452 unsigned int max, num_bufs, indirect = 0; 453 VRingDesc desc; 454 hwaddr desc_pa; 455 unsigned int i; 456 457 max = vq->vring.num; 458 num_bufs = total_bufs; 459 460 if (!virtqueue_get_head(vq, idx++, &i)) { 461 goto err; 462 } 463 464 desc_pa = vq->vring.desc; 465 vring_desc_read(vdev, &desc, desc_pa, i); 466 467 if (desc.flags & VRING_DESC_F_INDIRECT) { 468 if (desc.len % sizeof(VRingDesc)) { 469 virtio_error(vdev, "Invalid size for indirect buffer table"); 470 goto err; 471 } 472 473 /* If we've got too many, that implies a descriptor loop. */ 474 if (num_bufs >= max) { 475 virtio_error(vdev, "Looped descriptor"); 476 goto err; 477 } 478 479 /* loop over the indirect descriptor table */ 480 indirect = 1; 481 max = desc.len / sizeof(VRingDesc); 482 desc_pa = desc.addr; 483 num_bufs = i = 0; 484 vring_desc_read(vdev, &desc, desc_pa, i); 485 } 486 487 do { 488 /* If we've got too many, that implies a descriptor loop. */ 489 if (++num_bufs > max) { 490 virtio_error(vdev, "Looped descriptor"); 491 goto err; 492 } 493 494 if (desc.flags & VRING_DESC_F_WRITE) { 495 in_total += desc.len; 496 } else { 497 out_total += desc.len; 498 } 499 if (in_total >= max_in_bytes && out_total >= max_out_bytes) { 500 goto done; 501 } 502 503 rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i); 504 } while (rc == VIRTQUEUE_READ_DESC_MORE); 505 506 if (rc == VIRTQUEUE_READ_DESC_ERROR) { 507 goto err; 508 } 509 510 if (!indirect) 511 total_bufs = num_bufs; 512 else 513 total_bufs++; 514 } 515 516 if (rc < 0) { 517 goto err; 518 } 519 520 done: 521 if (in_bytes) { 522 *in_bytes = in_total; 523 } 524 if (out_bytes) { 525 *out_bytes = out_total; 526 } 527 return; 528 529 err: 530 in_total = out_total = 0; 531 goto done; 532 } 533 534 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes, 535 unsigned int out_bytes) 536 { 537 unsigned int in_total, out_total; 538 539 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes); 540 return in_bytes <= in_total && out_bytes <= out_total; 541 } 542 543 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg, 544 hwaddr *addr, struct iovec *iov, 545 unsigned int max_num_sg, bool is_write, 546 hwaddr pa, size_t sz) 547 { 548 bool ok = false; 549 unsigned num_sg = *p_num_sg; 550 assert(num_sg <= max_num_sg); 551 552 if (!sz) { 553 virtio_error(vdev, "virtio: zero sized buffers are not allowed"); 554 goto out; 555 } 556 557 while (sz) { 558 hwaddr len = sz; 559 560 if (num_sg == max_num_sg) { 561 virtio_error(vdev, "virtio: too many write descriptors in " 562 "indirect table"); 563 goto out; 564 } 565 566 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len, 567 is_write ? 568 DMA_DIRECTION_FROM_DEVICE : 569 DMA_DIRECTION_TO_DEVICE); 570 if (!iov[num_sg].iov_base) { 571 virtio_error(vdev, "virtio: bogus descriptor or out of resources"); 572 goto out; 573 } 574 575 iov[num_sg].iov_len = len; 576 addr[num_sg] = pa; 577 578 sz -= len; 579 pa += len; 580 num_sg++; 581 } 582 ok = true; 583 584 out: 585 *p_num_sg = num_sg; 586 return ok; 587 } 588 589 /* Only used by error code paths before we have a VirtQueueElement (therefore 590 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to 591 * yet. 592 */ 593 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num, 594 struct iovec *iov) 595 { 596 unsigned int i; 597 598 for (i = 0; i < out_num + in_num; i++) { 599 int is_write = i >= out_num; 600 601 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0); 602 iov++; 603 } 604 } 605 606 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg, 607 hwaddr *addr, unsigned int *num_sg, 608 unsigned int max_size, int is_write) 609 { 610 unsigned int i; 611 hwaddr len; 612 613 /* Note: this function MUST validate input, some callers 614 * are passing in num_sg values received over the network. 615 */ 616 /* TODO: teach all callers that this can fail, and return failure instead 617 * of asserting here. 618 * When we do, we might be able to re-enable NDEBUG below. 619 */ 620 #ifdef NDEBUG 621 #error building with NDEBUG is not supported 622 #endif 623 assert(*num_sg <= max_size); 624 625 for (i = 0; i < *num_sg; i++) { 626 len = sg[i].iov_len; 627 sg[i].iov_base = dma_memory_map(vdev->dma_as, 628 addr[i], &len, is_write ? 629 DMA_DIRECTION_FROM_DEVICE : 630 DMA_DIRECTION_TO_DEVICE); 631 if (!sg[i].iov_base) { 632 error_report("virtio: error trying to map MMIO memory"); 633 exit(1); 634 } 635 if (len != sg[i].iov_len) { 636 error_report("virtio: unexpected memory split"); 637 exit(1); 638 } 639 } 640 } 641 642 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem) 643 { 644 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 645 MIN(ARRAY_SIZE(elem->in_sg), ARRAY_SIZE(elem->in_addr)), 646 1); 647 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 648 MIN(ARRAY_SIZE(elem->out_sg), 649 ARRAY_SIZE(elem->out_addr)), 650 0); 651 } 652 653 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num) 654 { 655 VirtQueueElement *elem; 656 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0])); 657 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]); 658 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]); 659 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0])); 660 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]); 661 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]); 662 663 assert(sz >= sizeof(VirtQueueElement)); 664 elem = g_malloc(out_sg_end); 665 elem->out_num = out_num; 666 elem->in_num = in_num; 667 elem->in_addr = (void *)elem + in_addr_ofs; 668 elem->out_addr = (void *)elem + out_addr_ofs; 669 elem->in_sg = (void *)elem + in_sg_ofs; 670 elem->out_sg = (void *)elem + out_sg_ofs; 671 return elem; 672 } 673 674 void *virtqueue_pop(VirtQueue *vq, size_t sz) 675 { 676 unsigned int i, head, max; 677 hwaddr desc_pa = vq->vring.desc; 678 VirtIODevice *vdev = vq->vdev; 679 VirtQueueElement *elem; 680 unsigned out_num, in_num; 681 hwaddr addr[VIRTQUEUE_MAX_SIZE]; 682 struct iovec iov[VIRTQUEUE_MAX_SIZE]; 683 VRingDesc desc; 684 int rc; 685 686 if (unlikely(vdev->broken)) { 687 return NULL; 688 } 689 if (virtio_queue_empty(vq)) { 690 return NULL; 691 } 692 /* Needed after virtio_queue_empty(), see comment in 693 * virtqueue_num_heads(). */ 694 smp_rmb(); 695 696 /* When we start there are none of either input nor output. */ 697 out_num = in_num = 0; 698 699 max = vq->vring.num; 700 701 if (vq->inuse >= vq->vring.num) { 702 virtio_error(vdev, "Virtqueue size exceeded"); 703 return NULL; 704 } 705 706 if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) { 707 return NULL; 708 } 709 710 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { 711 vring_set_avail_event(vq, vq->last_avail_idx); 712 } 713 714 i = head; 715 vring_desc_read(vdev, &desc, desc_pa, i); 716 if (desc.flags & VRING_DESC_F_INDIRECT) { 717 if (desc.len % sizeof(VRingDesc)) { 718 virtio_error(vdev, "Invalid size for indirect buffer table"); 719 return NULL; 720 } 721 722 /* loop over the indirect descriptor table */ 723 max = desc.len / sizeof(VRingDesc); 724 desc_pa = desc.addr; 725 i = 0; 726 vring_desc_read(vdev, &desc, desc_pa, i); 727 } 728 729 /* Collect all the descriptors */ 730 do { 731 bool map_ok; 732 733 if (desc.flags & VRING_DESC_F_WRITE) { 734 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num, 735 iov + out_num, 736 VIRTQUEUE_MAX_SIZE - out_num, true, 737 desc.addr, desc.len); 738 } else { 739 if (in_num) { 740 virtio_error(vdev, "Incorrect order for descriptors"); 741 goto err_undo_map; 742 } 743 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov, 744 VIRTQUEUE_MAX_SIZE, false, 745 desc.addr, desc.len); 746 } 747 if (!map_ok) { 748 goto err_undo_map; 749 } 750 751 /* If we've got too many, that implies a descriptor loop. */ 752 if ((in_num + out_num) > max) { 753 virtio_error(vdev, "Looped descriptor"); 754 goto err_undo_map; 755 } 756 757 rc = virtqueue_read_next_desc(vdev, &desc, desc_pa, max, &i); 758 } while (rc == VIRTQUEUE_READ_DESC_MORE); 759 760 if (rc == VIRTQUEUE_READ_DESC_ERROR) { 761 goto err_undo_map; 762 } 763 764 /* Now copy what we have collected and mapped */ 765 elem = virtqueue_alloc_element(sz, out_num, in_num); 766 elem->index = head; 767 for (i = 0; i < out_num; i++) { 768 elem->out_addr[i] = addr[i]; 769 elem->out_sg[i] = iov[i]; 770 } 771 for (i = 0; i < in_num; i++) { 772 elem->in_addr[i] = addr[out_num + i]; 773 elem->in_sg[i] = iov[out_num + i]; 774 } 775 776 vq->inuse++; 777 778 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num); 779 return elem; 780 781 err_undo_map: 782 virtqueue_undo_map_desc(out_num, in_num, iov); 783 return NULL; 784 } 785 786 /* virtqueue_drop_all: 787 * @vq: The #VirtQueue 788 * Drops all queued buffers and indicates them to the guest 789 * as if they are done. Useful when buffers can not be 790 * processed but must be returned to the guest. 791 */ 792 unsigned int virtqueue_drop_all(VirtQueue *vq) 793 { 794 unsigned int dropped = 0; 795 VirtQueueElement elem = {}; 796 VirtIODevice *vdev = vq->vdev; 797 bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); 798 799 if (unlikely(vdev->broken)) { 800 return 0; 801 } 802 803 while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) { 804 /* works similar to virtqueue_pop but does not map buffers 805 * and does not allocate any memory */ 806 smp_rmb(); 807 if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) { 808 break; 809 } 810 vq->inuse++; 811 vq->last_avail_idx++; 812 if (fEventIdx) { 813 vring_set_avail_event(vq, vq->last_avail_idx); 814 } 815 /* immediately push the element, nothing to unmap 816 * as both in_num and out_num are set to 0 */ 817 virtqueue_push(vq, &elem, 0); 818 dropped++; 819 } 820 821 return dropped; 822 } 823 824 /* Reading and writing a structure directly to QEMUFile is *awful*, but 825 * it is what QEMU has always done by mistake. We can change it sooner 826 * or later by bumping the version number of the affected vm states. 827 * In the meanwhile, since the in-memory layout of VirtQueueElement 828 * has changed, we need to marshal to and from the layout that was 829 * used before the change. 830 */ 831 typedef struct VirtQueueElementOld { 832 unsigned int index; 833 unsigned int out_num; 834 unsigned int in_num; 835 hwaddr in_addr[VIRTQUEUE_MAX_SIZE]; 836 hwaddr out_addr[VIRTQUEUE_MAX_SIZE]; 837 struct iovec in_sg[VIRTQUEUE_MAX_SIZE]; 838 struct iovec out_sg[VIRTQUEUE_MAX_SIZE]; 839 } VirtQueueElementOld; 840 841 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz) 842 { 843 VirtQueueElement *elem; 844 VirtQueueElementOld data; 845 int i; 846 847 qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld)); 848 849 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num); 850 elem->index = data.index; 851 852 for (i = 0; i < elem->in_num; i++) { 853 elem->in_addr[i] = data.in_addr[i]; 854 } 855 856 for (i = 0; i < elem->out_num; i++) { 857 elem->out_addr[i] = data.out_addr[i]; 858 } 859 860 for (i = 0; i < elem->in_num; i++) { 861 /* Base is overwritten by virtqueue_map. */ 862 elem->in_sg[i].iov_base = 0; 863 elem->in_sg[i].iov_len = data.in_sg[i].iov_len; 864 } 865 866 for (i = 0; i < elem->out_num; i++) { 867 /* Base is overwritten by virtqueue_map. */ 868 elem->out_sg[i].iov_base = 0; 869 elem->out_sg[i].iov_len = data.out_sg[i].iov_len; 870 } 871 872 virtqueue_map(vdev, elem); 873 return elem; 874 } 875 876 void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem) 877 { 878 VirtQueueElementOld data; 879 int i; 880 881 memset(&data, 0, sizeof(data)); 882 data.index = elem->index; 883 data.in_num = elem->in_num; 884 data.out_num = elem->out_num; 885 886 for (i = 0; i < elem->in_num; i++) { 887 data.in_addr[i] = elem->in_addr[i]; 888 } 889 890 for (i = 0; i < elem->out_num; i++) { 891 data.out_addr[i] = elem->out_addr[i]; 892 } 893 894 for (i = 0; i < elem->in_num; i++) { 895 /* Base is overwritten by virtqueue_map when loading. Do not 896 * save it, as it would leak the QEMU address space layout. */ 897 data.in_sg[i].iov_len = elem->in_sg[i].iov_len; 898 } 899 900 for (i = 0; i < elem->out_num; i++) { 901 /* Do not save iov_base as above. */ 902 data.out_sg[i].iov_len = elem->out_sg[i].iov_len; 903 } 904 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld)); 905 } 906 907 /* virtio device */ 908 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector) 909 { 910 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 911 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 912 913 if (unlikely(vdev->broken)) { 914 return; 915 } 916 917 if (k->notify) { 918 k->notify(qbus->parent, vector); 919 } 920 } 921 922 void virtio_update_irq(VirtIODevice *vdev) 923 { 924 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); 925 } 926 927 static int virtio_validate_features(VirtIODevice *vdev) 928 { 929 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 930 931 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) && 932 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) { 933 return -EFAULT; 934 } 935 936 if (k->validate_features) { 937 return k->validate_features(vdev); 938 } else { 939 return 0; 940 } 941 } 942 943 int virtio_set_status(VirtIODevice *vdev, uint8_t val) 944 { 945 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 946 trace_virtio_set_status(vdev, val); 947 948 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 949 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) && 950 val & VIRTIO_CONFIG_S_FEATURES_OK) { 951 int ret = virtio_validate_features(vdev); 952 953 if (ret) { 954 return ret; 955 } 956 } 957 } 958 if (k->set_status) { 959 k->set_status(vdev, val); 960 } 961 vdev->status = val; 962 return 0; 963 } 964 965 bool target_words_bigendian(void); 966 static enum virtio_device_endian virtio_default_endian(void) 967 { 968 if (target_words_bigendian()) { 969 return VIRTIO_DEVICE_ENDIAN_BIG; 970 } else { 971 return VIRTIO_DEVICE_ENDIAN_LITTLE; 972 } 973 } 974 975 static enum virtio_device_endian virtio_current_cpu_endian(void) 976 { 977 CPUClass *cc = CPU_GET_CLASS(current_cpu); 978 979 if (cc->virtio_is_big_endian(current_cpu)) { 980 return VIRTIO_DEVICE_ENDIAN_BIG; 981 } else { 982 return VIRTIO_DEVICE_ENDIAN_LITTLE; 983 } 984 } 985 986 void virtio_reset(void *opaque) 987 { 988 VirtIODevice *vdev = opaque; 989 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 990 int i; 991 992 virtio_set_status(vdev, 0); 993 if (current_cpu) { 994 /* Guest initiated reset */ 995 vdev->device_endian = virtio_current_cpu_endian(); 996 } else { 997 /* System reset */ 998 vdev->device_endian = virtio_default_endian(); 999 } 1000 1001 if (k->reset) { 1002 k->reset(vdev); 1003 } 1004 1005 vdev->broken = false; 1006 vdev->guest_features = 0; 1007 vdev->queue_sel = 0; 1008 vdev->status = 0; 1009 atomic_set(&vdev->isr, 0); 1010 vdev->config_vector = VIRTIO_NO_VECTOR; 1011 virtio_notify_vector(vdev, vdev->config_vector); 1012 1013 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1014 vdev->vq[i].vring.desc = 0; 1015 vdev->vq[i].vring.avail = 0; 1016 vdev->vq[i].vring.used = 0; 1017 vdev->vq[i].last_avail_idx = 0; 1018 vdev->vq[i].shadow_avail_idx = 0; 1019 vdev->vq[i].used_idx = 0; 1020 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR); 1021 vdev->vq[i].signalled_used = 0; 1022 vdev->vq[i].signalled_used_valid = false; 1023 vdev->vq[i].notification_disabled = 0; 1024 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default; 1025 vdev->vq[i].inuse = 0; 1026 } 1027 } 1028 1029 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr) 1030 { 1031 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1032 uint8_t val; 1033 1034 if (addr + sizeof(val) > vdev->config_len) { 1035 return (uint32_t)-1; 1036 } 1037 1038 k->get_config(vdev, vdev->config); 1039 1040 val = ldub_p(vdev->config + addr); 1041 return val; 1042 } 1043 1044 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr) 1045 { 1046 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1047 uint16_t val; 1048 1049 if (addr + sizeof(val) > vdev->config_len) { 1050 return (uint32_t)-1; 1051 } 1052 1053 k->get_config(vdev, vdev->config); 1054 1055 val = lduw_p(vdev->config + addr); 1056 return val; 1057 } 1058 1059 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr) 1060 { 1061 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1062 uint32_t val; 1063 1064 if (addr + sizeof(val) > vdev->config_len) { 1065 return (uint32_t)-1; 1066 } 1067 1068 k->get_config(vdev, vdev->config); 1069 1070 val = ldl_p(vdev->config + addr); 1071 return val; 1072 } 1073 1074 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data) 1075 { 1076 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1077 uint8_t val = data; 1078 1079 if (addr + sizeof(val) > vdev->config_len) { 1080 return; 1081 } 1082 1083 stb_p(vdev->config + addr, val); 1084 1085 if (k->set_config) { 1086 k->set_config(vdev, vdev->config); 1087 } 1088 } 1089 1090 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data) 1091 { 1092 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1093 uint16_t val = data; 1094 1095 if (addr + sizeof(val) > vdev->config_len) { 1096 return; 1097 } 1098 1099 stw_p(vdev->config + addr, val); 1100 1101 if (k->set_config) { 1102 k->set_config(vdev, vdev->config); 1103 } 1104 } 1105 1106 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data) 1107 { 1108 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1109 uint32_t val = data; 1110 1111 if (addr + sizeof(val) > vdev->config_len) { 1112 return; 1113 } 1114 1115 stl_p(vdev->config + addr, val); 1116 1117 if (k->set_config) { 1118 k->set_config(vdev, vdev->config); 1119 } 1120 } 1121 1122 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr) 1123 { 1124 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1125 uint8_t val; 1126 1127 if (addr + sizeof(val) > vdev->config_len) { 1128 return (uint32_t)-1; 1129 } 1130 1131 k->get_config(vdev, vdev->config); 1132 1133 val = ldub_p(vdev->config + addr); 1134 return val; 1135 } 1136 1137 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr) 1138 { 1139 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1140 uint16_t val; 1141 1142 if (addr + sizeof(val) > vdev->config_len) { 1143 return (uint32_t)-1; 1144 } 1145 1146 k->get_config(vdev, vdev->config); 1147 1148 val = lduw_le_p(vdev->config + addr); 1149 return val; 1150 } 1151 1152 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr) 1153 { 1154 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1155 uint32_t val; 1156 1157 if (addr + sizeof(val) > vdev->config_len) { 1158 return (uint32_t)-1; 1159 } 1160 1161 k->get_config(vdev, vdev->config); 1162 1163 val = ldl_le_p(vdev->config + addr); 1164 return val; 1165 } 1166 1167 void virtio_config_modern_writeb(VirtIODevice *vdev, 1168 uint32_t addr, uint32_t data) 1169 { 1170 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1171 uint8_t val = data; 1172 1173 if (addr + sizeof(val) > vdev->config_len) { 1174 return; 1175 } 1176 1177 stb_p(vdev->config + addr, val); 1178 1179 if (k->set_config) { 1180 k->set_config(vdev, vdev->config); 1181 } 1182 } 1183 1184 void virtio_config_modern_writew(VirtIODevice *vdev, 1185 uint32_t addr, uint32_t data) 1186 { 1187 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1188 uint16_t val = data; 1189 1190 if (addr + sizeof(val) > vdev->config_len) { 1191 return; 1192 } 1193 1194 stw_le_p(vdev->config + addr, val); 1195 1196 if (k->set_config) { 1197 k->set_config(vdev, vdev->config); 1198 } 1199 } 1200 1201 void virtio_config_modern_writel(VirtIODevice *vdev, 1202 uint32_t addr, uint32_t data) 1203 { 1204 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1205 uint32_t val = data; 1206 1207 if (addr + sizeof(val) > vdev->config_len) { 1208 return; 1209 } 1210 1211 stl_le_p(vdev->config + addr, val); 1212 1213 if (k->set_config) { 1214 k->set_config(vdev, vdev->config); 1215 } 1216 } 1217 1218 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr) 1219 { 1220 vdev->vq[n].vring.desc = addr; 1221 virtio_queue_update_rings(vdev, n); 1222 } 1223 1224 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n) 1225 { 1226 return vdev->vq[n].vring.desc; 1227 } 1228 1229 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc, 1230 hwaddr avail, hwaddr used) 1231 { 1232 vdev->vq[n].vring.desc = desc; 1233 vdev->vq[n].vring.avail = avail; 1234 vdev->vq[n].vring.used = used; 1235 } 1236 1237 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num) 1238 { 1239 /* Don't allow guest to flip queue between existent and 1240 * nonexistent states, or to set it to an invalid size. 1241 */ 1242 if (!!num != !!vdev->vq[n].vring.num || 1243 num > VIRTQUEUE_MAX_SIZE || 1244 num < 0) { 1245 return; 1246 } 1247 vdev->vq[n].vring.num = num; 1248 } 1249 1250 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector) 1251 { 1252 return QLIST_FIRST(&vdev->vector_queues[vector]); 1253 } 1254 1255 VirtQueue *virtio_vector_next_queue(VirtQueue *vq) 1256 { 1257 return QLIST_NEXT(vq, node); 1258 } 1259 1260 int virtio_queue_get_num(VirtIODevice *vdev, int n) 1261 { 1262 return vdev->vq[n].vring.num; 1263 } 1264 1265 int virtio_get_num_queues(VirtIODevice *vdev) 1266 { 1267 int i; 1268 1269 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1270 if (!virtio_queue_get_num(vdev, i)) { 1271 break; 1272 } 1273 } 1274 1275 return i; 1276 } 1277 1278 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align) 1279 { 1280 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1281 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1282 1283 /* virtio-1 compliant devices cannot change the alignment */ 1284 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 1285 error_report("tried to modify queue alignment for virtio-1 device"); 1286 return; 1287 } 1288 /* Check that the transport told us it was going to do this 1289 * (so a buggy transport will immediately assert rather than 1290 * silently failing to migrate this state) 1291 */ 1292 assert(k->has_variable_vring_alignment); 1293 1294 vdev->vq[n].vring.align = align; 1295 virtio_queue_update_rings(vdev, n); 1296 } 1297 1298 static void virtio_queue_notify_aio_vq(VirtQueue *vq) 1299 { 1300 if (vq->vring.desc && vq->handle_aio_output) { 1301 VirtIODevice *vdev = vq->vdev; 1302 1303 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); 1304 vq->handle_aio_output(vdev, vq); 1305 } 1306 } 1307 1308 static void virtio_queue_notify_vq(VirtQueue *vq) 1309 { 1310 if (vq->vring.desc && vq->handle_output) { 1311 VirtIODevice *vdev = vq->vdev; 1312 1313 if (unlikely(vdev->broken)) { 1314 return; 1315 } 1316 1317 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq); 1318 vq->handle_output(vdev, vq); 1319 } 1320 } 1321 1322 void virtio_queue_notify(VirtIODevice *vdev, int n) 1323 { 1324 virtio_queue_notify_vq(&vdev->vq[n]); 1325 } 1326 1327 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n) 1328 { 1329 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector : 1330 VIRTIO_NO_VECTOR; 1331 } 1332 1333 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector) 1334 { 1335 VirtQueue *vq = &vdev->vq[n]; 1336 1337 if (n < VIRTIO_QUEUE_MAX) { 1338 if (vdev->vector_queues && 1339 vdev->vq[n].vector != VIRTIO_NO_VECTOR) { 1340 QLIST_REMOVE(vq, node); 1341 } 1342 vdev->vq[n].vector = vector; 1343 if (vdev->vector_queues && 1344 vector != VIRTIO_NO_VECTOR) { 1345 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node); 1346 } 1347 } 1348 } 1349 1350 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size, 1351 VirtIOHandleOutput handle_output) 1352 { 1353 int i; 1354 1355 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1356 if (vdev->vq[i].vring.num == 0) 1357 break; 1358 } 1359 1360 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE) 1361 abort(); 1362 1363 vdev->vq[i].vring.num = queue_size; 1364 vdev->vq[i].vring.num_default = queue_size; 1365 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN; 1366 vdev->vq[i].handle_output = handle_output; 1367 vdev->vq[i].handle_aio_output = NULL; 1368 1369 return &vdev->vq[i]; 1370 } 1371 1372 void virtio_del_queue(VirtIODevice *vdev, int n) 1373 { 1374 if (n < 0 || n >= VIRTIO_QUEUE_MAX) { 1375 abort(); 1376 } 1377 1378 vdev->vq[n].vring.num = 0; 1379 vdev->vq[n].vring.num_default = 0; 1380 } 1381 1382 static void virtio_set_isr(VirtIODevice *vdev, int value) 1383 { 1384 uint8_t old = atomic_read(&vdev->isr); 1385 1386 /* Do not write ISR if it does not change, so that its cacheline remains 1387 * shared in the common case where the guest does not read it. 1388 */ 1389 if ((old & value) != value) { 1390 atomic_or(&vdev->isr, value); 1391 } 1392 } 1393 1394 bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq) 1395 { 1396 uint16_t old, new; 1397 bool v; 1398 /* We need to expose used array entries before checking used event. */ 1399 smp_mb(); 1400 /* Always notify when queue is empty (when feature acknowledge) */ 1401 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) && 1402 !vq->inuse && virtio_queue_empty(vq)) { 1403 return true; 1404 } 1405 1406 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) { 1407 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT); 1408 } 1409 1410 v = vq->signalled_used_valid; 1411 vq->signalled_used_valid = true; 1412 old = vq->signalled_used; 1413 new = vq->signalled_used = vq->used_idx; 1414 return !v || vring_need_event(vring_get_used_event(vq), new, old); 1415 } 1416 1417 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq) 1418 { 1419 if (!virtio_should_notify(vdev, vq)) { 1420 return; 1421 } 1422 1423 trace_virtio_notify_irqfd(vdev, vq); 1424 1425 /* 1426 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but 1427 * windows drivers included in virtio-win 1.8.0 (circa 2015) are 1428 * incorrectly polling this bit during crashdump and hibernation 1429 * in MSI mode, causing a hang if this bit is never updated. 1430 * Recent releases of Windows do not really shut down, but rather 1431 * log out and hibernate to make the next startup faster. Hence, 1432 * this manifested as a more serious hang during shutdown with 1433 * 1434 * Next driver release from 2016 fixed this problem, so working around it 1435 * is not a must, but it's easy to do so let's do it here. 1436 * 1437 * Note: it's safe to update ISR from any thread as it was switched 1438 * to an atomic operation. 1439 */ 1440 virtio_set_isr(vq->vdev, 0x1); 1441 event_notifier_set(&vq->guest_notifier); 1442 } 1443 1444 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq) 1445 { 1446 if (!virtio_should_notify(vdev, vq)) { 1447 return; 1448 } 1449 1450 trace_virtio_notify(vdev, vq); 1451 virtio_set_isr(vq->vdev, 0x1); 1452 virtio_notify_vector(vdev, vq->vector); 1453 } 1454 1455 void virtio_notify_config(VirtIODevice *vdev) 1456 { 1457 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) 1458 return; 1459 1460 virtio_set_isr(vdev, 0x3); 1461 vdev->generation++; 1462 virtio_notify_vector(vdev, vdev->config_vector); 1463 } 1464 1465 static bool virtio_device_endian_needed(void *opaque) 1466 { 1467 VirtIODevice *vdev = opaque; 1468 1469 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN); 1470 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 1471 return vdev->device_endian != virtio_default_endian(); 1472 } 1473 /* Devices conforming to VIRTIO 1.0 or later are always LE. */ 1474 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE; 1475 } 1476 1477 static bool virtio_64bit_features_needed(void *opaque) 1478 { 1479 VirtIODevice *vdev = opaque; 1480 1481 return (vdev->host_features >> 32) != 0; 1482 } 1483 1484 static bool virtio_virtqueue_needed(void *opaque) 1485 { 1486 VirtIODevice *vdev = opaque; 1487 1488 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1); 1489 } 1490 1491 static bool virtio_ringsize_needed(void *opaque) 1492 { 1493 VirtIODevice *vdev = opaque; 1494 int i; 1495 1496 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1497 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) { 1498 return true; 1499 } 1500 } 1501 return false; 1502 } 1503 1504 static bool virtio_extra_state_needed(void *opaque) 1505 { 1506 VirtIODevice *vdev = opaque; 1507 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1508 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1509 1510 return k->has_extra_state && 1511 k->has_extra_state(qbus->parent); 1512 } 1513 1514 static bool virtio_broken_needed(void *opaque) 1515 { 1516 VirtIODevice *vdev = opaque; 1517 1518 return vdev->broken; 1519 } 1520 1521 static const VMStateDescription vmstate_virtqueue = { 1522 .name = "virtqueue_state", 1523 .version_id = 1, 1524 .minimum_version_id = 1, 1525 .fields = (VMStateField[]) { 1526 VMSTATE_UINT64(vring.avail, struct VirtQueue), 1527 VMSTATE_UINT64(vring.used, struct VirtQueue), 1528 VMSTATE_END_OF_LIST() 1529 } 1530 }; 1531 1532 static const VMStateDescription vmstate_virtio_virtqueues = { 1533 .name = "virtio/virtqueues", 1534 .version_id = 1, 1535 .minimum_version_id = 1, 1536 .needed = &virtio_virtqueue_needed, 1537 .fields = (VMStateField[]) { 1538 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice, 1539 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue), 1540 VMSTATE_END_OF_LIST() 1541 } 1542 }; 1543 1544 static const VMStateDescription vmstate_ringsize = { 1545 .name = "ringsize_state", 1546 .version_id = 1, 1547 .minimum_version_id = 1, 1548 .fields = (VMStateField[]) { 1549 VMSTATE_UINT32(vring.num_default, struct VirtQueue), 1550 VMSTATE_END_OF_LIST() 1551 } 1552 }; 1553 1554 static const VMStateDescription vmstate_virtio_ringsize = { 1555 .name = "virtio/ringsize", 1556 .version_id = 1, 1557 .minimum_version_id = 1, 1558 .needed = &virtio_ringsize_needed, 1559 .fields = (VMStateField[]) { 1560 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice, 1561 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue), 1562 VMSTATE_END_OF_LIST() 1563 } 1564 }; 1565 1566 static int get_extra_state(QEMUFile *f, void *pv, size_t size) 1567 { 1568 VirtIODevice *vdev = pv; 1569 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1570 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1571 1572 if (!k->load_extra_state) { 1573 return -1; 1574 } else { 1575 return k->load_extra_state(qbus->parent, f); 1576 } 1577 } 1578 1579 static void put_extra_state(QEMUFile *f, void *pv, size_t size) 1580 { 1581 VirtIODevice *vdev = pv; 1582 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1583 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1584 1585 k->save_extra_state(qbus->parent, f); 1586 } 1587 1588 static const VMStateInfo vmstate_info_extra_state = { 1589 .name = "virtqueue_extra_state", 1590 .get = get_extra_state, 1591 .put = put_extra_state, 1592 }; 1593 1594 static const VMStateDescription vmstate_virtio_extra_state = { 1595 .name = "virtio/extra_state", 1596 .version_id = 1, 1597 .minimum_version_id = 1, 1598 .needed = &virtio_extra_state_needed, 1599 .fields = (VMStateField[]) { 1600 { 1601 .name = "extra_state", 1602 .version_id = 0, 1603 .field_exists = NULL, 1604 .size = 0, 1605 .info = &vmstate_info_extra_state, 1606 .flags = VMS_SINGLE, 1607 .offset = 0, 1608 }, 1609 VMSTATE_END_OF_LIST() 1610 } 1611 }; 1612 1613 static const VMStateDescription vmstate_virtio_device_endian = { 1614 .name = "virtio/device_endian", 1615 .version_id = 1, 1616 .minimum_version_id = 1, 1617 .needed = &virtio_device_endian_needed, 1618 .fields = (VMStateField[]) { 1619 VMSTATE_UINT8(device_endian, VirtIODevice), 1620 VMSTATE_END_OF_LIST() 1621 } 1622 }; 1623 1624 static const VMStateDescription vmstate_virtio_64bit_features = { 1625 .name = "virtio/64bit_features", 1626 .version_id = 1, 1627 .minimum_version_id = 1, 1628 .needed = &virtio_64bit_features_needed, 1629 .fields = (VMStateField[]) { 1630 VMSTATE_UINT64(guest_features, VirtIODevice), 1631 VMSTATE_END_OF_LIST() 1632 } 1633 }; 1634 1635 static const VMStateDescription vmstate_virtio_broken = { 1636 .name = "virtio/broken", 1637 .version_id = 1, 1638 .minimum_version_id = 1, 1639 .needed = &virtio_broken_needed, 1640 .fields = (VMStateField[]) { 1641 VMSTATE_BOOL(broken, VirtIODevice), 1642 VMSTATE_END_OF_LIST() 1643 } 1644 }; 1645 1646 static const VMStateDescription vmstate_virtio = { 1647 .name = "virtio", 1648 .version_id = 1, 1649 .minimum_version_id = 1, 1650 .minimum_version_id_old = 1, 1651 .fields = (VMStateField[]) { 1652 VMSTATE_END_OF_LIST() 1653 }, 1654 .subsections = (const VMStateDescription*[]) { 1655 &vmstate_virtio_device_endian, 1656 &vmstate_virtio_64bit_features, 1657 &vmstate_virtio_virtqueues, 1658 &vmstate_virtio_ringsize, 1659 &vmstate_virtio_broken, 1660 &vmstate_virtio_extra_state, 1661 NULL 1662 } 1663 }; 1664 1665 void virtio_save(VirtIODevice *vdev, QEMUFile *f) 1666 { 1667 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1668 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1669 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); 1670 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff); 1671 int i; 1672 1673 if (k->save_config) { 1674 k->save_config(qbus->parent, f); 1675 } 1676 1677 qemu_put_8s(f, &vdev->status); 1678 qemu_put_8s(f, &vdev->isr); 1679 qemu_put_be16s(f, &vdev->queue_sel); 1680 qemu_put_be32s(f, &guest_features_lo); 1681 qemu_put_be32(f, vdev->config_len); 1682 qemu_put_buffer(f, vdev->config, vdev->config_len); 1683 1684 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1685 if (vdev->vq[i].vring.num == 0) 1686 break; 1687 } 1688 1689 qemu_put_be32(f, i); 1690 1691 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 1692 if (vdev->vq[i].vring.num == 0) 1693 break; 1694 1695 qemu_put_be32(f, vdev->vq[i].vring.num); 1696 if (k->has_variable_vring_alignment) { 1697 qemu_put_be32(f, vdev->vq[i].vring.align); 1698 } 1699 /* XXX virtio-1 devices */ 1700 qemu_put_be64(f, vdev->vq[i].vring.desc); 1701 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx); 1702 if (k->save_queue) { 1703 k->save_queue(qbus->parent, i, f); 1704 } 1705 } 1706 1707 if (vdc->save != NULL) { 1708 vdc->save(vdev, f); 1709 } 1710 1711 if (vdc->vmsd) { 1712 vmstate_save_state(f, vdc->vmsd, vdev, NULL); 1713 } 1714 1715 /* Subsections */ 1716 vmstate_save_state(f, &vmstate_virtio, vdev, NULL); 1717 } 1718 1719 /* A wrapper for use as a VMState .put function */ 1720 static void virtio_device_put(QEMUFile *f, void *opaque, size_t size) 1721 { 1722 virtio_save(VIRTIO_DEVICE(opaque), f); 1723 } 1724 1725 /* A wrapper for use as a VMState .get function */ 1726 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size) 1727 { 1728 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 1729 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev)); 1730 1731 return virtio_load(vdev, f, dc->vmsd->version_id); 1732 } 1733 1734 const VMStateInfo virtio_vmstate_info = { 1735 .name = "virtio", 1736 .get = virtio_device_get, 1737 .put = virtio_device_put, 1738 }; 1739 1740 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val) 1741 { 1742 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev); 1743 bool bad = (val & ~(vdev->host_features)) != 0; 1744 1745 val &= vdev->host_features; 1746 if (k->set_features) { 1747 k->set_features(vdev, val); 1748 } 1749 vdev->guest_features = val; 1750 return bad ? -1 : 0; 1751 } 1752 1753 int virtio_set_features(VirtIODevice *vdev, uint64_t val) 1754 { 1755 /* 1756 * The driver must not attempt to set features after feature negotiation 1757 * has finished. 1758 */ 1759 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) { 1760 return -EINVAL; 1761 } 1762 return virtio_set_features_nocheck(vdev, val); 1763 } 1764 1765 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id) 1766 { 1767 int i, ret; 1768 int32_t config_len; 1769 uint32_t num; 1770 uint32_t features; 1771 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1772 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1773 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev); 1774 1775 /* 1776 * We poison the endianness to ensure it does not get used before 1777 * subsections have been loaded. 1778 */ 1779 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN; 1780 1781 if (k->load_config) { 1782 ret = k->load_config(qbus->parent, f); 1783 if (ret) 1784 return ret; 1785 } 1786 1787 qemu_get_8s(f, &vdev->status); 1788 qemu_get_8s(f, &vdev->isr); 1789 qemu_get_be16s(f, &vdev->queue_sel); 1790 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) { 1791 return -1; 1792 } 1793 qemu_get_be32s(f, &features); 1794 1795 /* 1796 * Temporarily set guest_features low bits - needed by 1797 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS 1798 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ. 1799 * 1800 * Note: devices should always test host features in future - don't create 1801 * new dependencies like this. 1802 */ 1803 vdev->guest_features = features; 1804 1805 config_len = qemu_get_be32(f); 1806 1807 /* 1808 * There are cases where the incoming config can be bigger or smaller 1809 * than what we have; so load what we have space for, and skip 1810 * any excess that's in the stream. 1811 */ 1812 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len)); 1813 1814 while (config_len > vdev->config_len) { 1815 qemu_get_byte(f); 1816 config_len--; 1817 } 1818 1819 num = qemu_get_be32(f); 1820 1821 if (num > VIRTIO_QUEUE_MAX) { 1822 error_report("Invalid number of virtqueues: 0x%x", num); 1823 return -1; 1824 } 1825 1826 for (i = 0; i < num; i++) { 1827 vdev->vq[i].vring.num = qemu_get_be32(f); 1828 if (k->has_variable_vring_alignment) { 1829 vdev->vq[i].vring.align = qemu_get_be32(f); 1830 } 1831 vdev->vq[i].vring.desc = qemu_get_be64(f); 1832 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx); 1833 vdev->vq[i].signalled_used_valid = false; 1834 vdev->vq[i].notification_disabled = 0; 1835 1836 if (vdev->vq[i].vring.desc) { 1837 /* XXX virtio-1 devices */ 1838 virtio_queue_update_rings(vdev, i); 1839 } else if (vdev->vq[i].last_avail_idx) { 1840 error_report("VQ %d address 0x0 " 1841 "inconsistent with Host index 0x%x", 1842 i, vdev->vq[i].last_avail_idx); 1843 return -1; 1844 } 1845 if (k->load_queue) { 1846 ret = k->load_queue(qbus->parent, i, f); 1847 if (ret) 1848 return ret; 1849 } 1850 } 1851 1852 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR); 1853 1854 if (vdc->load != NULL) { 1855 ret = vdc->load(vdev, f, version_id); 1856 if (ret) { 1857 return ret; 1858 } 1859 } 1860 1861 if (vdc->vmsd) { 1862 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id); 1863 if (ret) { 1864 return ret; 1865 } 1866 } 1867 1868 /* Subsections */ 1869 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1); 1870 if (ret) { 1871 return ret; 1872 } 1873 1874 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) { 1875 vdev->device_endian = virtio_default_endian(); 1876 } 1877 1878 if (virtio_64bit_features_needed(vdev)) { 1879 /* 1880 * Subsection load filled vdev->guest_features. Run them 1881 * through virtio_set_features to sanity-check them against 1882 * host_features. 1883 */ 1884 uint64_t features64 = vdev->guest_features; 1885 if (virtio_set_features_nocheck(vdev, features64) < 0) { 1886 error_report("Features 0x%" PRIx64 " unsupported. " 1887 "Allowed features: 0x%" PRIx64, 1888 features64, vdev->host_features); 1889 return -1; 1890 } 1891 } else { 1892 if (virtio_set_features_nocheck(vdev, features) < 0) { 1893 error_report("Features 0x%x unsupported. " 1894 "Allowed features: 0x%" PRIx64, 1895 features, vdev->host_features); 1896 return -1; 1897 } 1898 } 1899 1900 for (i = 0; i < num; i++) { 1901 if (vdev->vq[i].vring.desc) { 1902 uint16_t nheads; 1903 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx; 1904 /* Check it isn't doing strange things with descriptor numbers. */ 1905 if (nheads > vdev->vq[i].vring.num) { 1906 error_report("VQ %d size 0x%x Guest index 0x%x " 1907 "inconsistent with Host index 0x%x: delta 0x%x", 1908 i, vdev->vq[i].vring.num, 1909 vring_avail_idx(&vdev->vq[i]), 1910 vdev->vq[i].last_avail_idx, nheads); 1911 return -1; 1912 } 1913 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]); 1914 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]); 1915 1916 /* 1917 * Some devices migrate VirtQueueElements that have been popped 1918 * from the avail ring but not yet returned to the used ring. 1919 * Since max ring size < UINT16_MAX it's safe to use modulo 1920 * UINT16_MAX + 1 subtraction. 1921 */ 1922 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx - 1923 vdev->vq[i].used_idx); 1924 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) { 1925 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - " 1926 "used_idx 0x%x", 1927 i, vdev->vq[i].vring.num, 1928 vdev->vq[i].last_avail_idx, 1929 vdev->vq[i].used_idx); 1930 return -1; 1931 } 1932 } 1933 } 1934 1935 return 0; 1936 } 1937 1938 void virtio_cleanup(VirtIODevice *vdev) 1939 { 1940 qemu_del_vm_change_state_handler(vdev->vmstate); 1941 g_free(vdev->config); 1942 g_free(vdev->vq); 1943 g_free(vdev->vector_queues); 1944 } 1945 1946 static void virtio_vmstate_change(void *opaque, int running, RunState state) 1947 { 1948 VirtIODevice *vdev = opaque; 1949 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1950 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1951 bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK); 1952 vdev->vm_running = running; 1953 1954 if (backend_run) { 1955 virtio_set_status(vdev, vdev->status); 1956 } 1957 1958 if (k->vmstate_change) { 1959 k->vmstate_change(qbus->parent, backend_run); 1960 } 1961 1962 if (!backend_run) { 1963 virtio_set_status(vdev, vdev->status); 1964 } 1965 } 1966 1967 void virtio_instance_init_common(Object *proxy_obj, void *data, 1968 size_t vdev_size, const char *vdev_name) 1969 { 1970 DeviceState *vdev = data; 1971 1972 object_initialize(vdev, vdev_size, vdev_name); 1973 object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL); 1974 object_unref(OBJECT(vdev)); 1975 qdev_alias_all_properties(vdev, proxy_obj); 1976 } 1977 1978 void virtio_init(VirtIODevice *vdev, const char *name, 1979 uint16_t device_id, size_t config_size) 1980 { 1981 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 1982 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus); 1983 int i; 1984 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0; 1985 1986 if (nvectors) { 1987 vdev->vector_queues = 1988 g_malloc0(sizeof(*vdev->vector_queues) * nvectors); 1989 } 1990 1991 vdev->device_id = device_id; 1992 vdev->status = 0; 1993 atomic_set(&vdev->isr, 0); 1994 vdev->queue_sel = 0; 1995 vdev->config_vector = VIRTIO_NO_VECTOR; 1996 vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX); 1997 vdev->vm_running = runstate_is_running(); 1998 vdev->broken = false; 1999 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) { 2000 vdev->vq[i].vector = VIRTIO_NO_VECTOR; 2001 vdev->vq[i].vdev = vdev; 2002 vdev->vq[i].queue_index = i; 2003 } 2004 2005 vdev->name = name; 2006 vdev->config_len = config_size; 2007 if (vdev->config_len) { 2008 vdev->config = g_malloc0(config_size); 2009 } else { 2010 vdev->config = NULL; 2011 } 2012 vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change, 2013 vdev); 2014 vdev->device_endian = virtio_default_endian(); 2015 vdev->use_guest_notifier_mask = true; 2016 } 2017 2018 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n) 2019 { 2020 return vdev->vq[n].vring.desc; 2021 } 2022 2023 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n) 2024 { 2025 return vdev->vq[n].vring.avail; 2026 } 2027 2028 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n) 2029 { 2030 return vdev->vq[n].vring.used; 2031 } 2032 2033 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n) 2034 { 2035 return sizeof(VRingDesc) * vdev->vq[n].vring.num; 2036 } 2037 2038 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n) 2039 { 2040 return offsetof(VRingAvail, ring) + 2041 sizeof(uint16_t) * vdev->vq[n].vring.num; 2042 } 2043 2044 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n) 2045 { 2046 return offsetof(VRingUsed, ring) + 2047 sizeof(VRingUsedElem) * vdev->vq[n].vring.num; 2048 } 2049 2050 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n) 2051 { 2052 return vdev->vq[n].last_avail_idx; 2053 } 2054 2055 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx) 2056 { 2057 vdev->vq[n].last_avail_idx = idx; 2058 vdev->vq[n].shadow_avail_idx = idx; 2059 } 2060 2061 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n) 2062 { 2063 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]); 2064 } 2065 2066 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n) 2067 { 2068 vdev->vq[n].signalled_used_valid = false; 2069 } 2070 2071 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n) 2072 { 2073 return vdev->vq + n; 2074 } 2075 2076 uint16_t virtio_get_queue_index(VirtQueue *vq) 2077 { 2078 return vq->queue_index; 2079 } 2080 2081 static void virtio_queue_guest_notifier_read(EventNotifier *n) 2082 { 2083 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier); 2084 if (event_notifier_test_and_clear(n)) { 2085 virtio_notify_vector(vq->vdev, vq->vector); 2086 } 2087 } 2088 2089 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign, 2090 bool with_irqfd) 2091 { 2092 if (assign && !with_irqfd) { 2093 event_notifier_set_handler(&vq->guest_notifier, 2094 virtio_queue_guest_notifier_read); 2095 } else { 2096 event_notifier_set_handler(&vq->guest_notifier, NULL); 2097 } 2098 if (!assign) { 2099 /* Test and clear notifier before closing it, 2100 * in case poll callback didn't have time to run. */ 2101 virtio_queue_guest_notifier_read(&vq->guest_notifier); 2102 } 2103 } 2104 2105 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq) 2106 { 2107 return &vq->guest_notifier; 2108 } 2109 2110 static void virtio_queue_host_notifier_aio_read(EventNotifier *n) 2111 { 2112 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 2113 if (event_notifier_test_and_clear(n)) { 2114 virtio_queue_notify_aio_vq(vq); 2115 } 2116 } 2117 2118 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n) 2119 { 2120 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 2121 2122 virtio_queue_set_notification(vq, 0); 2123 } 2124 2125 static bool virtio_queue_host_notifier_aio_poll(void *opaque) 2126 { 2127 EventNotifier *n = opaque; 2128 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 2129 2130 if (virtio_queue_empty(vq)) { 2131 return false; 2132 } 2133 2134 virtio_queue_notify_aio_vq(vq); 2135 return true; 2136 } 2137 2138 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n) 2139 { 2140 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 2141 2142 /* Caller polls once more after this to catch requests that race with us */ 2143 virtio_queue_set_notification(vq, 1); 2144 } 2145 2146 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx, 2147 VirtIOHandleOutput handle_output) 2148 { 2149 if (handle_output) { 2150 vq->handle_aio_output = handle_output; 2151 aio_set_event_notifier(ctx, &vq->host_notifier, true, 2152 virtio_queue_host_notifier_aio_read, 2153 virtio_queue_host_notifier_aio_poll); 2154 aio_set_event_notifier_poll(ctx, &vq->host_notifier, 2155 virtio_queue_host_notifier_aio_poll_begin, 2156 virtio_queue_host_notifier_aio_poll_end); 2157 } else { 2158 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL); 2159 /* Test and clear notifier before after disabling event, 2160 * in case poll callback didn't have time to run. */ 2161 virtio_queue_host_notifier_aio_read(&vq->host_notifier); 2162 vq->handle_aio_output = NULL; 2163 } 2164 } 2165 2166 void virtio_queue_host_notifier_read(EventNotifier *n) 2167 { 2168 VirtQueue *vq = container_of(n, VirtQueue, host_notifier); 2169 if (event_notifier_test_and_clear(n)) { 2170 virtio_queue_notify_vq(vq); 2171 } 2172 } 2173 2174 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq) 2175 { 2176 return &vq->host_notifier; 2177 } 2178 2179 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name) 2180 { 2181 g_free(vdev->bus_name); 2182 vdev->bus_name = g_strdup(bus_name); 2183 } 2184 2185 void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...) 2186 { 2187 va_list ap; 2188 2189 va_start(ap, fmt); 2190 error_vreport(fmt, ap); 2191 va_end(ap); 2192 2193 vdev->broken = true; 2194 2195 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { 2196 virtio_set_status(vdev, vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET); 2197 virtio_notify_config(vdev); 2198 } 2199 } 2200 2201 static void virtio_device_realize(DeviceState *dev, Error **errp) 2202 { 2203 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 2204 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev); 2205 Error *err = NULL; 2206 2207 /* Devices should either use vmsd or the load/save methods */ 2208 assert(!vdc->vmsd || !vdc->load); 2209 2210 if (vdc->realize != NULL) { 2211 vdc->realize(dev, &err); 2212 if (err != NULL) { 2213 error_propagate(errp, err); 2214 return; 2215 } 2216 } 2217 2218 virtio_bus_device_plugged(vdev, &err); 2219 if (err != NULL) { 2220 error_propagate(errp, err); 2221 return; 2222 } 2223 } 2224 2225 static void virtio_device_unrealize(DeviceState *dev, Error **errp) 2226 { 2227 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 2228 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev); 2229 Error *err = NULL; 2230 2231 virtio_bus_device_unplugged(vdev); 2232 2233 if (vdc->unrealize != NULL) { 2234 vdc->unrealize(dev, &err); 2235 if (err != NULL) { 2236 error_propagate(errp, err); 2237 return; 2238 } 2239 } 2240 2241 g_free(vdev->bus_name); 2242 vdev->bus_name = NULL; 2243 } 2244 2245 static Property virtio_properties[] = { 2246 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features), 2247 DEFINE_PROP_END_OF_LIST(), 2248 }; 2249 2250 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev) 2251 { 2252 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); 2253 int n, r, err; 2254 2255 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 2256 VirtQueue *vq = &vdev->vq[n]; 2257 if (!virtio_queue_get_num(vdev, n)) { 2258 continue; 2259 } 2260 r = virtio_bus_set_host_notifier(qbus, n, true); 2261 if (r < 0) { 2262 err = r; 2263 goto assign_error; 2264 } 2265 event_notifier_set_handler(&vq->host_notifier, 2266 virtio_queue_host_notifier_read); 2267 } 2268 2269 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 2270 /* Kick right away to begin processing requests already in vring */ 2271 VirtQueue *vq = &vdev->vq[n]; 2272 if (!vq->vring.num) { 2273 continue; 2274 } 2275 event_notifier_set(&vq->host_notifier); 2276 } 2277 return 0; 2278 2279 assign_error: 2280 while (--n >= 0) { 2281 VirtQueue *vq = &vdev->vq[n]; 2282 if (!virtio_queue_get_num(vdev, n)) { 2283 continue; 2284 } 2285 2286 event_notifier_set_handler(&vq->host_notifier, NULL); 2287 r = virtio_bus_set_host_notifier(qbus, n, false); 2288 assert(r >= 0); 2289 } 2290 return err; 2291 } 2292 2293 int virtio_device_start_ioeventfd(VirtIODevice *vdev) 2294 { 2295 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2296 VirtioBusState *vbus = VIRTIO_BUS(qbus); 2297 2298 return virtio_bus_start_ioeventfd(vbus); 2299 } 2300 2301 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev) 2302 { 2303 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev))); 2304 int n, r; 2305 2306 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) { 2307 VirtQueue *vq = &vdev->vq[n]; 2308 2309 if (!virtio_queue_get_num(vdev, n)) { 2310 continue; 2311 } 2312 event_notifier_set_handler(&vq->host_notifier, NULL); 2313 r = virtio_bus_set_host_notifier(qbus, n, false); 2314 assert(r >= 0); 2315 } 2316 } 2317 2318 void virtio_device_stop_ioeventfd(VirtIODevice *vdev) 2319 { 2320 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2321 VirtioBusState *vbus = VIRTIO_BUS(qbus); 2322 2323 virtio_bus_stop_ioeventfd(vbus); 2324 } 2325 2326 int virtio_device_grab_ioeventfd(VirtIODevice *vdev) 2327 { 2328 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2329 VirtioBusState *vbus = VIRTIO_BUS(qbus); 2330 2331 return virtio_bus_grab_ioeventfd(vbus); 2332 } 2333 2334 void virtio_device_release_ioeventfd(VirtIODevice *vdev) 2335 { 2336 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2337 VirtioBusState *vbus = VIRTIO_BUS(qbus); 2338 2339 virtio_bus_release_ioeventfd(vbus); 2340 } 2341 2342 static void virtio_device_class_init(ObjectClass *klass, void *data) 2343 { 2344 /* Set the default value here. */ 2345 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 2346 DeviceClass *dc = DEVICE_CLASS(klass); 2347 2348 dc->realize = virtio_device_realize; 2349 dc->unrealize = virtio_device_unrealize; 2350 dc->bus_type = TYPE_VIRTIO_BUS; 2351 dc->props = virtio_properties; 2352 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl; 2353 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl; 2354 2355 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES; 2356 } 2357 2358 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev) 2359 { 2360 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev)); 2361 VirtioBusState *vbus = VIRTIO_BUS(qbus); 2362 2363 return virtio_bus_ioeventfd_enabled(vbus); 2364 } 2365 2366 static const TypeInfo virtio_device_info = { 2367 .name = TYPE_VIRTIO_DEVICE, 2368 .parent = TYPE_DEVICE, 2369 .instance_size = sizeof(VirtIODevice), 2370 .class_init = virtio_device_class_init, 2371 .abstract = true, 2372 .class_size = sizeof(VirtioDeviceClass), 2373 }; 2374 2375 static void virtio_register_types(void) 2376 { 2377 type_register_static(&virtio_device_info); 2378 } 2379 2380 type_init(virtio_register_types) 2381