1 /* 2 * Virtio Block Device 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 "qemu/iov.h" 18 #include "qemu/error-report.h" 19 #include "trace.h" 20 #include "hw/block/block.h" 21 #include "sysemu/blockdev.h" 22 #include "hw/virtio/virtio-blk.h" 23 #include "dataplane/virtio-blk.h" 24 #include "scsi/constants.h" 25 #ifdef __linux__ 26 # include <scsi/sg.h> 27 #endif 28 #include "hw/virtio/virtio-bus.h" 29 #include "hw/virtio/virtio-access.h" 30 31 static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq, 32 VirtIOBlockReq *req) 33 { 34 req->dev = s; 35 req->vq = vq; 36 req->qiov.size = 0; 37 req->in_len = 0; 38 req->next = NULL; 39 req->mr_next = NULL; 40 } 41 42 static void virtio_blk_free_request(VirtIOBlockReq *req) 43 { 44 g_free(req); 45 } 46 47 static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) 48 { 49 VirtIOBlock *s = req->dev; 50 VirtIODevice *vdev = VIRTIO_DEVICE(s); 51 52 trace_virtio_blk_req_complete(vdev, req, status); 53 54 stb_p(&req->in->status, status); 55 virtqueue_push(req->vq, &req->elem, req->in_len); 56 if (s->dataplane_started && !s->dataplane_disabled) { 57 virtio_blk_data_plane_notify(s->dataplane, req->vq); 58 } else { 59 virtio_notify(vdev, req->vq); 60 } 61 } 62 63 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, 64 bool is_read) 65 { 66 VirtIOBlock *s = req->dev; 67 BlockErrorAction action = blk_get_error_action(s->blk, is_read, error); 68 69 if (action == BLOCK_ERROR_ACTION_STOP) { 70 /* Break the link as the next request is going to be parsed from the 71 * ring again. Otherwise we may end up doing a double completion! */ 72 req->mr_next = NULL; 73 req->next = s->rq; 74 s->rq = req; 75 } else if (action == BLOCK_ERROR_ACTION_REPORT) { 76 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 77 block_acct_failed(blk_get_stats(s->blk), &req->acct); 78 virtio_blk_free_request(req); 79 } 80 81 blk_error_action(s->blk, action, is_read, error); 82 return action != BLOCK_ERROR_ACTION_IGNORE; 83 } 84 85 static void virtio_blk_rw_complete(void *opaque, int ret) 86 { 87 VirtIOBlockReq *next = opaque; 88 VirtIOBlock *s = next->dev; 89 VirtIODevice *vdev = VIRTIO_DEVICE(s); 90 91 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 92 while (next) { 93 VirtIOBlockReq *req = next; 94 next = req->mr_next; 95 trace_virtio_blk_rw_complete(vdev, req, ret); 96 97 if (req->qiov.nalloc != -1) { 98 /* If nalloc is != -1 req->qiov is a local copy of the original 99 * external iovec. It was allocated in submit_requests to be 100 * able to merge requests. */ 101 qemu_iovec_destroy(&req->qiov); 102 } 103 104 if (ret) { 105 int p = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); 106 bool is_read = !(p & VIRTIO_BLK_T_OUT); 107 /* Note that memory may be dirtied on read failure. If the 108 * virtio request is not completed here, as is the case for 109 * BLOCK_ERROR_ACTION_STOP, the memory may not be copied 110 * correctly during live migration. While this is ugly, 111 * it is acceptable because the device is free to write to 112 * the memory until the request is completed (which will 113 * happen on the other side of the migration). 114 */ 115 if (virtio_blk_handle_rw_error(req, -ret, is_read)) { 116 continue; 117 } 118 } 119 120 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 121 block_acct_done(blk_get_stats(req->dev->blk), &req->acct); 122 virtio_blk_free_request(req); 123 } 124 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 125 } 126 127 static void virtio_blk_flush_complete(void *opaque, int ret) 128 { 129 VirtIOBlockReq *req = opaque; 130 VirtIOBlock *s = req->dev; 131 132 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 133 if (ret) { 134 if (virtio_blk_handle_rw_error(req, -ret, 0)) { 135 goto out; 136 } 137 } 138 139 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 140 block_acct_done(blk_get_stats(s->blk), &req->acct); 141 virtio_blk_free_request(req); 142 143 out: 144 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 145 } 146 147 #ifdef __linux__ 148 149 typedef struct { 150 VirtIOBlockReq *req; 151 struct sg_io_hdr hdr; 152 } VirtIOBlockIoctlReq; 153 154 static void virtio_blk_ioctl_complete(void *opaque, int status) 155 { 156 VirtIOBlockIoctlReq *ioctl_req = opaque; 157 VirtIOBlockReq *req = ioctl_req->req; 158 VirtIOBlock *s = req->dev; 159 VirtIODevice *vdev = VIRTIO_DEVICE(s); 160 struct virtio_scsi_inhdr *scsi; 161 struct sg_io_hdr *hdr; 162 163 scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; 164 165 if (status) { 166 status = VIRTIO_BLK_S_UNSUPP; 167 virtio_stl_p(vdev, &scsi->errors, 255); 168 goto out; 169 } 170 171 hdr = &ioctl_req->hdr; 172 /* 173 * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi) 174 * clear the masked_status field [hence status gets cleared too, see 175 * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED 176 * status has occurred. However they do set DRIVER_SENSE in driver_status 177 * field. Also a (sb_len_wr > 0) indicates there is a sense buffer. 178 */ 179 if (hdr->status == 0 && hdr->sb_len_wr > 0) { 180 hdr->status = CHECK_CONDITION; 181 } 182 183 virtio_stl_p(vdev, &scsi->errors, 184 hdr->status | (hdr->msg_status << 8) | 185 (hdr->host_status << 16) | (hdr->driver_status << 24)); 186 virtio_stl_p(vdev, &scsi->residual, hdr->resid); 187 virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr); 188 virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len); 189 190 out: 191 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 192 virtio_blk_req_complete(req, status); 193 virtio_blk_free_request(req); 194 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 195 g_free(ioctl_req); 196 } 197 198 #endif 199 200 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s, VirtQueue *vq) 201 { 202 VirtIOBlockReq *req = virtqueue_pop(vq, sizeof(VirtIOBlockReq)); 203 204 if (req) { 205 virtio_blk_init_request(s, vq, req); 206 } 207 return req; 208 } 209 210 static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) 211 { 212 int status = VIRTIO_BLK_S_OK; 213 struct virtio_scsi_inhdr *scsi = NULL; 214 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); 215 VirtQueueElement *elem = &req->elem; 216 VirtIOBlock *blk = req->dev; 217 218 #ifdef __linux__ 219 int i; 220 VirtIOBlockIoctlReq *ioctl_req; 221 BlockAIOCB *acb; 222 #endif 223 224 /* 225 * We require at least one output segment each for the virtio_blk_outhdr 226 * and the SCSI command block. 227 * 228 * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr 229 * and the sense buffer pointer in the input segments. 230 */ 231 if (elem->out_num < 2 || elem->in_num < 3) { 232 status = VIRTIO_BLK_S_IOERR; 233 goto fail; 234 } 235 236 /* 237 * The scsi inhdr is placed in the second-to-last input segment, just 238 * before the regular inhdr. 239 */ 240 scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base; 241 242 if (!blk->conf.scsi) { 243 status = VIRTIO_BLK_S_UNSUPP; 244 goto fail; 245 } 246 247 /* 248 * No support for bidirection commands yet. 249 */ 250 if (elem->out_num > 2 && elem->in_num > 3) { 251 status = VIRTIO_BLK_S_UNSUPP; 252 goto fail; 253 } 254 255 #ifdef __linux__ 256 ioctl_req = g_new0(VirtIOBlockIoctlReq, 1); 257 ioctl_req->req = req; 258 ioctl_req->hdr.interface_id = 'S'; 259 ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len; 260 ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base; 261 ioctl_req->hdr.dxfer_len = 0; 262 263 if (elem->out_num > 2) { 264 /* 265 * If there are more than the minimally required 2 output segments 266 * there is write payload starting from the third iovec. 267 */ 268 ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV; 269 ioctl_req->hdr.iovec_count = elem->out_num - 2; 270 271 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 272 ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len; 273 } 274 275 ioctl_req->hdr.dxferp = elem->out_sg + 2; 276 277 } else if (elem->in_num > 3) { 278 /* 279 * If we have more than 3 input segments the guest wants to actually 280 * read data. 281 */ 282 ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV; 283 ioctl_req->hdr.iovec_count = elem->in_num - 3; 284 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 285 ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len; 286 } 287 288 ioctl_req->hdr.dxferp = elem->in_sg; 289 } else { 290 /* 291 * Some SCSI commands don't actually transfer any data. 292 */ 293 ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE; 294 } 295 296 ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base; 297 ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len; 298 299 acb = blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr, 300 virtio_blk_ioctl_complete, ioctl_req); 301 if (!acb) { 302 g_free(ioctl_req); 303 status = VIRTIO_BLK_S_UNSUPP; 304 goto fail; 305 } 306 return -EINPROGRESS; 307 #else 308 abort(); 309 #endif 310 311 fail: 312 /* Just put anything nonzero so that the ioctl fails in the guest. */ 313 if (scsi) { 314 virtio_stl_p(vdev, &scsi->errors, 255); 315 } 316 return status; 317 } 318 319 static void virtio_blk_handle_scsi(VirtIOBlockReq *req) 320 { 321 int status; 322 323 status = virtio_blk_handle_scsi_req(req); 324 if (status != -EINPROGRESS) { 325 virtio_blk_req_complete(req, status); 326 virtio_blk_free_request(req); 327 } 328 } 329 330 static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb, 331 int start, int num_reqs, int niov) 332 { 333 QEMUIOVector *qiov = &mrb->reqs[start]->qiov; 334 int64_t sector_num = mrb->reqs[start]->sector_num; 335 bool is_write = mrb->is_write; 336 337 if (num_reqs > 1) { 338 int i; 339 struct iovec *tmp_iov = qiov->iov; 340 int tmp_niov = qiov->niov; 341 342 /* mrb->reqs[start]->qiov was initialized from external so we can't 343 * modify it here. We need to initialize it locally and then add the 344 * external iovecs. */ 345 qemu_iovec_init(qiov, niov); 346 347 for (i = 0; i < tmp_niov; i++) { 348 qemu_iovec_add(qiov, tmp_iov[i].iov_base, tmp_iov[i].iov_len); 349 } 350 351 for (i = start + 1; i < start + num_reqs; i++) { 352 qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0, 353 mrb->reqs[i]->qiov.size); 354 mrb->reqs[i - 1]->mr_next = mrb->reqs[i]; 355 } 356 357 trace_virtio_blk_submit_multireq(VIRTIO_DEVICE(mrb->reqs[start]->dev), 358 mrb, start, num_reqs, 359 sector_num << BDRV_SECTOR_BITS, 360 qiov->size, is_write); 361 block_acct_merge_done(blk_get_stats(blk), 362 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ, 363 num_reqs - 1); 364 } 365 366 if (is_write) { 367 blk_aio_pwritev(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0, 368 virtio_blk_rw_complete, mrb->reqs[start]); 369 } else { 370 blk_aio_preadv(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0, 371 virtio_blk_rw_complete, mrb->reqs[start]); 372 } 373 } 374 375 static int multireq_compare(const void *a, const void *b) 376 { 377 const VirtIOBlockReq *req1 = *(VirtIOBlockReq **)a, 378 *req2 = *(VirtIOBlockReq **)b; 379 380 /* 381 * Note that we can't simply subtract sector_num1 from sector_num2 382 * here as that could overflow the return value. 383 */ 384 if (req1->sector_num > req2->sector_num) { 385 return 1; 386 } else if (req1->sector_num < req2->sector_num) { 387 return -1; 388 } else { 389 return 0; 390 } 391 } 392 393 static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) 394 { 395 int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0; 396 uint32_t max_transfer; 397 int64_t sector_num = 0; 398 399 if (mrb->num_reqs == 1) { 400 submit_requests(blk, mrb, 0, 1, -1); 401 mrb->num_reqs = 0; 402 return; 403 } 404 405 max_transfer = blk_get_max_transfer(mrb->reqs[0]->dev->blk); 406 407 qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs), 408 &multireq_compare); 409 410 for (i = 0; i < mrb->num_reqs; i++) { 411 VirtIOBlockReq *req = mrb->reqs[i]; 412 if (num_reqs > 0) { 413 /* 414 * NOTE: We cannot merge the requests in below situations: 415 * 1. requests are not sequential 416 * 2. merge would exceed maximum number of IOVs 417 * 3. merge would exceed maximum transfer length of backend device 418 */ 419 if (sector_num + nb_sectors != req->sector_num || 420 niov > blk_get_max_iov(blk) - req->qiov.niov || 421 req->qiov.size > max_transfer || 422 nb_sectors > (max_transfer - 423 req->qiov.size) / BDRV_SECTOR_SIZE) { 424 submit_requests(blk, mrb, start, num_reqs, niov); 425 num_reqs = 0; 426 } 427 } 428 429 if (num_reqs == 0) { 430 sector_num = req->sector_num; 431 nb_sectors = niov = 0; 432 start = i; 433 } 434 435 nb_sectors += req->qiov.size / BDRV_SECTOR_SIZE; 436 niov += req->qiov.niov; 437 num_reqs++; 438 } 439 440 submit_requests(blk, mrb, start, num_reqs, niov); 441 mrb->num_reqs = 0; 442 } 443 444 static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb) 445 { 446 block_acct_start(blk_get_stats(req->dev->blk), &req->acct, 0, 447 BLOCK_ACCT_FLUSH); 448 449 /* 450 * Make sure all outstanding writes are posted to the backing device. 451 */ 452 if (mrb->is_write && mrb->num_reqs > 0) { 453 virtio_blk_submit_multireq(req->dev->blk, mrb); 454 } 455 blk_aio_flush(req->dev->blk, virtio_blk_flush_complete, req); 456 } 457 458 static bool virtio_blk_sect_range_ok(VirtIOBlock *dev, 459 uint64_t sector, size_t size) 460 { 461 uint64_t nb_sectors = size >> BDRV_SECTOR_BITS; 462 uint64_t total_sectors; 463 464 if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) { 465 return false; 466 } 467 if (sector & dev->sector_mask) { 468 return false; 469 } 470 if (size % dev->conf.conf.logical_block_size) { 471 return false; 472 } 473 blk_get_geometry(dev->blk, &total_sectors); 474 if (sector > total_sectors || nb_sectors > total_sectors - sector) { 475 return false; 476 } 477 return true; 478 } 479 480 static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) 481 { 482 uint32_t type; 483 struct iovec *in_iov = req->elem.in_sg; 484 struct iovec *out_iov = req->elem.out_sg; 485 unsigned in_num = req->elem.in_num; 486 unsigned out_num = req->elem.out_num; 487 VirtIOBlock *s = req->dev; 488 VirtIODevice *vdev = VIRTIO_DEVICE(s); 489 490 if (req->elem.out_num < 1 || req->elem.in_num < 1) { 491 virtio_error(vdev, "virtio-blk missing headers"); 492 return -1; 493 } 494 495 if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out, 496 sizeof(req->out)) != sizeof(req->out))) { 497 virtio_error(vdev, "virtio-blk request outhdr too short"); 498 return -1; 499 } 500 501 iov_discard_front(&out_iov, &out_num, sizeof(req->out)); 502 503 if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { 504 virtio_error(vdev, "virtio-blk request inhdr too short"); 505 return -1; 506 } 507 508 /* We always touch the last byte, so just see how big in_iov is. */ 509 req->in_len = iov_size(in_iov, in_num); 510 req->in = (void *)in_iov[in_num - 1].iov_base 511 + in_iov[in_num - 1].iov_len 512 - sizeof(struct virtio_blk_inhdr); 513 iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); 514 515 type = virtio_ldl_p(vdev, &req->out.type); 516 517 /* VIRTIO_BLK_T_OUT defines the command direction. VIRTIO_BLK_T_BARRIER 518 * is an optional flag. Although a guest should not send this flag if 519 * not negotiated we ignored it in the past. So keep ignoring it. */ 520 switch (type & ~(VIRTIO_BLK_T_OUT | VIRTIO_BLK_T_BARRIER)) { 521 case VIRTIO_BLK_T_IN: 522 { 523 bool is_write = type & VIRTIO_BLK_T_OUT; 524 req->sector_num = virtio_ldq_p(vdev, &req->out.sector); 525 526 if (is_write) { 527 qemu_iovec_init_external(&req->qiov, out_iov, out_num); 528 trace_virtio_blk_handle_write(vdev, req, req->sector_num, 529 req->qiov.size / BDRV_SECTOR_SIZE); 530 } else { 531 qemu_iovec_init_external(&req->qiov, in_iov, in_num); 532 trace_virtio_blk_handle_read(vdev, req, req->sector_num, 533 req->qiov.size / BDRV_SECTOR_SIZE); 534 } 535 536 if (!virtio_blk_sect_range_ok(s, req->sector_num, req->qiov.size)) { 537 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 538 block_acct_invalid(blk_get_stats(s->blk), 539 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 540 virtio_blk_free_request(req); 541 return 0; 542 } 543 544 block_acct_start(blk_get_stats(s->blk), &req->acct, req->qiov.size, 545 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 546 547 /* merge would exceed maximum number of requests or IO direction 548 * changes */ 549 if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS || 550 is_write != mrb->is_write || 551 !s->conf.request_merging)) { 552 virtio_blk_submit_multireq(s->blk, mrb); 553 } 554 555 assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS); 556 mrb->reqs[mrb->num_reqs++] = req; 557 mrb->is_write = is_write; 558 break; 559 } 560 case VIRTIO_BLK_T_FLUSH: 561 virtio_blk_handle_flush(req, mrb); 562 break; 563 case VIRTIO_BLK_T_SCSI_CMD: 564 virtio_blk_handle_scsi(req); 565 break; 566 case VIRTIO_BLK_T_GET_ID: 567 { 568 /* 569 * NB: per existing s/n string convention the string is 570 * terminated by '\0' only when shorter than buffer. 571 */ 572 const char *serial = s->conf.serial ? s->conf.serial : ""; 573 size_t size = MIN(strlen(serial) + 1, 574 MIN(iov_size(in_iov, in_num), 575 VIRTIO_BLK_ID_BYTES)); 576 iov_from_buf(in_iov, in_num, 0, serial, size); 577 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 578 virtio_blk_free_request(req); 579 break; 580 } 581 default: 582 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); 583 virtio_blk_free_request(req); 584 } 585 return 0; 586 } 587 588 bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) 589 { 590 VirtIOBlockReq *req; 591 MultiReqBuffer mrb = {}; 592 bool progress = false; 593 594 aio_context_acquire(blk_get_aio_context(s->blk)); 595 blk_io_plug(s->blk); 596 597 do { 598 virtio_queue_set_notification(vq, 0); 599 600 while ((req = virtio_blk_get_request(s, vq))) { 601 progress = true; 602 if (virtio_blk_handle_request(req, &mrb)) { 603 virtqueue_detach_element(req->vq, &req->elem, 0); 604 virtio_blk_free_request(req); 605 break; 606 } 607 } 608 609 virtio_queue_set_notification(vq, 1); 610 } while (!virtio_queue_empty(vq)); 611 612 if (mrb.num_reqs) { 613 virtio_blk_submit_multireq(s->blk, &mrb); 614 } 615 616 blk_io_unplug(s->blk); 617 aio_context_release(blk_get_aio_context(s->blk)); 618 return progress; 619 } 620 621 static void virtio_blk_handle_output_do(VirtIOBlock *s, VirtQueue *vq) 622 { 623 virtio_blk_handle_vq(s, vq); 624 } 625 626 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) 627 { 628 VirtIOBlock *s = (VirtIOBlock *)vdev; 629 630 if (s->dataplane) { 631 /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start 632 * dataplane here instead of waiting for .set_status(). 633 */ 634 virtio_device_start_ioeventfd(vdev); 635 if (!s->dataplane_disabled) { 636 return; 637 } 638 } 639 virtio_blk_handle_output_do(s, vq); 640 } 641 642 static void virtio_blk_dma_restart_bh(void *opaque) 643 { 644 VirtIOBlock *s = opaque; 645 VirtIOBlockReq *req = s->rq; 646 MultiReqBuffer mrb = {}; 647 648 qemu_bh_delete(s->bh); 649 s->bh = NULL; 650 651 s->rq = NULL; 652 653 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 654 while (req) { 655 VirtIOBlockReq *next = req->next; 656 if (virtio_blk_handle_request(req, &mrb)) { 657 /* Device is now broken and won't do any processing until it gets 658 * reset. Already queued requests will be lost: let's purge them. 659 */ 660 while (req) { 661 next = req->next; 662 virtqueue_detach_element(req->vq, &req->elem, 0); 663 virtio_blk_free_request(req); 664 req = next; 665 } 666 break; 667 } 668 req = next; 669 } 670 671 if (mrb.num_reqs) { 672 virtio_blk_submit_multireq(s->blk, &mrb); 673 } 674 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 675 } 676 677 static void virtio_blk_dma_restart_cb(void *opaque, int running, 678 RunState state) 679 { 680 VirtIOBlock *s = opaque; 681 682 if (!running) { 683 return; 684 } 685 686 if (!s->bh) { 687 s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk), 688 virtio_blk_dma_restart_bh, s); 689 qemu_bh_schedule(s->bh); 690 } 691 } 692 693 static void virtio_blk_reset(VirtIODevice *vdev) 694 { 695 VirtIOBlock *s = VIRTIO_BLK(vdev); 696 AioContext *ctx; 697 VirtIOBlockReq *req; 698 699 ctx = blk_get_aio_context(s->blk); 700 aio_context_acquire(ctx); 701 blk_drain(s->blk); 702 703 /* We drop queued requests after blk_drain() because blk_drain() itself can 704 * produce them. */ 705 while (s->rq) { 706 req = s->rq; 707 s->rq = req->next; 708 virtqueue_detach_element(req->vq, &req->elem, 0); 709 virtio_blk_free_request(req); 710 } 711 712 aio_context_release(ctx); 713 714 assert(!s->dataplane_started); 715 blk_set_enable_write_cache(s->blk, s->original_wce); 716 } 717 718 /* coalesce internal state, copy to pci i/o region 0 719 */ 720 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) 721 { 722 VirtIOBlock *s = VIRTIO_BLK(vdev); 723 BlockConf *conf = &s->conf.conf; 724 struct virtio_blk_config blkcfg; 725 uint64_t capacity; 726 int64_t length; 727 int blk_size = conf->logical_block_size; 728 729 blk_get_geometry(s->blk, &capacity); 730 memset(&blkcfg, 0, sizeof(blkcfg)); 731 virtio_stq_p(vdev, &blkcfg.capacity, capacity); 732 virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); 733 virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls); 734 virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); 735 virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); 736 virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size); 737 blkcfg.geometry.heads = conf->heads; 738 /* 739 * We must ensure that the block device capacity is a multiple of 740 * the logical block size. If that is not the case, let's use 741 * sector_mask to adopt the geometry to have a correct picture. 742 * For those devices where the capacity is ok for the given geometry 743 * we don't touch the sector value of the geometry, since some devices 744 * (like s390 dasd) need a specific value. Here the capacity is already 745 * cyls*heads*secs*blk_size and the sector value is not block size 746 * divided by 512 - instead it is the amount of blk_size blocks 747 * per track (cylinder). 748 */ 749 length = blk_getlength(s->blk); 750 if (length > 0 && length / conf->heads / conf->secs % blk_size) { 751 blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; 752 } else { 753 blkcfg.geometry.sectors = conf->secs; 754 } 755 blkcfg.size_max = 0; 756 blkcfg.physical_block_exp = get_physical_block_exp(conf); 757 blkcfg.alignment_offset = 0; 758 blkcfg.wce = blk_enable_write_cache(s->blk); 759 virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues); 760 memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); 761 } 762 763 static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) 764 { 765 VirtIOBlock *s = VIRTIO_BLK(vdev); 766 struct virtio_blk_config blkcfg; 767 768 memcpy(&blkcfg, config, sizeof(blkcfg)); 769 770 aio_context_acquire(blk_get_aio_context(s->blk)); 771 blk_set_enable_write_cache(s->blk, blkcfg.wce != 0); 772 aio_context_release(blk_get_aio_context(s->blk)); 773 } 774 775 static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, 776 Error **errp) 777 { 778 VirtIOBlock *s = VIRTIO_BLK(vdev); 779 780 virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX); 781 virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY); 782 virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY); 783 virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE); 784 if (virtio_has_feature(features, VIRTIO_F_VERSION_1)) { 785 if (s->conf.scsi) { 786 error_setg(errp, "Please set scsi=off for virtio-blk devices in order to use virtio 1.0"); 787 return 0; 788 } 789 } else { 790 virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT); 791 virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); 792 } 793 794 if (s->conf.config_wce) { 795 virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE); 796 } 797 if (blk_enable_write_cache(s->blk)) { 798 virtio_add_feature(&features, VIRTIO_BLK_F_WCE); 799 } 800 if (blk_is_read_only(s->blk)) { 801 virtio_add_feature(&features, VIRTIO_BLK_F_RO); 802 } 803 if (s->conf.num_queues > 1) { 804 virtio_add_feature(&features, VIRTIO_BLK_F_MQ); 805 } 806 807 return features; 808 } 809 810 static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status) 811 { 812 VirtIOBlock *s = VIRTIO_BLK(vdev); 813 814 if (!(status & (VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK))) { 815 assert(!s->dataplane_started); 816 } 817 818 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) { 819 return; 820 } 821 822 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send 823 * cache flushes. Thus, the "auto writethrough" behavior is never 824 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature. 825 * Leaving it enabled would break the following sequence: 826 * 827 * Guest started with "-drive cache=writethrough" 828 * Guest sets status to 0 829 * Guest sets DRIVER bit in status field 830 * Guest reads host features (WCE=0, CONFIG_WCE=1) 831 * Guest writes guest features (WCE=0, CONFIG_WCE=1) 832 * Guest writes 1 to the WCE configuration field (writeback mode) 833 * Guest sets DRIVER_OK bit in status field 834 * 835 * s->blk would erroneously be placed in writethrough mode. 836 */ 837 if (!virtio_vdev_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) { 838 aio_context_acquire(blk_get_aio_context(s->blk)); 839 blk_set_enable_write_cache(s->blk, 840 virtio_vdev_has_feature(vdev, 841 VIRTIO_BLK_F_WCE)); 842 aio_context_release(blk_get_aio_context(s->blk)); 843 } 844 } 845 846 static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f) 847 { 848 VirtIOBlock *s = VIRTIO_BLK(vdev); 849 VirtIOBlockReq *req = s->rq; 850 851 while (req) { 852 qemu_put_sbyte(f, 1); 853 854 if (s->conf.num_queues > 1) { 855 qemu_put_be32(f, virtio_get_queue_index(req->vq)); 856 } 857 858 qemu_put_virtqueue_element(f, &req->elem); 859 req = req->next; 860 } 861 qemu_put_sbyte(f, 0); 862 } 863 864 static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f, 865 int version_id) 866 { 867 VirtIOBlock *s = VIRTIO_BLK(vdev); 868 869 while (qemu_get_sbyte(f)) { 870 unsigned nvqs = s->conf.num_queues; 871 unsigned vq_idx = 0; 872 VirtIOBlockReq *req; 873 874 if (nvqs > 1) { 875 vq_idx = qemu_get_be32(f); 876 877 if (vq_idx >= nvqs) { 878 error_report("Invalid virtqueue index in request list: %#x", 879 vq_idx); 880 return -EINVAL; 881 } 882 } 883 884 req = qemu_get_virtqueue_element(vdev, f, sizeof(VirtIOBlockReq)); 885 virtio_blk_init_request(s, virtio_get_queue(vdev, vq_idx), req); 886 req->next = s->rq; 887 s->rq = req; 888 } 889 890 return 0; 891 } 892 893 static void virtio_blk_resize(void *opaque) 894 { 895 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 896 897 virtio_notify_config(vdev); 898 } 899 900 static const BlockDevOps virtio_block_ops = { 901 .resize_cb = virtio_blk_resize, 902 }; 903 904 static void virtio_blk_device_realize(DeviceState *dev, Error **errp) 905 { 906 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 907 VirtIOBlock *s = VIRTIO_BLK(dev); 908 VirtIOBlkConf *conf = &s->conf; 909 Error *err = NULL; 910 unsigned i; 911 912 if (!conf->conf.blk) { 913 error_setg(errp, "drive property not set"); 914 return; 915 } 916 if (!blk_is_inserted(conf->conf.blk)) { 917 error_setg(errp, "Device needs media, but drive is empty"); 918 return; 919 } 920 if (!conf->num_queues) { 921 error_setg(errp, "num-queues property must be larger than 0"); 922 return; 923 } 924 if (!is_power_of_2(conf->queue_size) || 925 conf->queue_size > VIRTQUEUE_MAX_SIZE) { 926 error_setg(errp, "invalid queue-size property (%" PRIu16 "), " 927 "must be a power of 2 (max %d)", 928 conf->queue_size, VIRTQUEUE_MAX_SIZE); 929 return; 930 } 931 932 if (!blkconf_apply_backend_options(&conf->conf, 933 blk_is_read_only(conf->conf.blk), true, 934 errp)) { 935 return; 936 } 937 s->original_wce = blk_enable_write_cache(conf->conf.blk); 938 if (!blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, errp)) { 939 return; 940 } 941 942 blkconf_blocksizes(&conf->conf); 943 944 if (conf->conf.logical_block_size > 945 conf->conf.physical_block_size) { 946 error_setg(errp, 947 "logical_block_size > physical_block_size not supported"); 948 return; 949 } 950 951 virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, 952 sizeof(struct virtio_blk_config)); 953 954 s->blk = conf->conf.blk; 955 s->rq = NULL; 956 s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1; 957 958 for (i = 0; i < conf->num_queues; i++) { 959 virtio_add_queue(vdev, conf->queue_size, virtio_blk_handle_output); 960 } 961 virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err); 962 if (err != NULL) { 963 error_propagate(errp, err); 964 virtio_cleanup(vdev); 965 return; 966 } 967 968 s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); 969 blk_set_dev_ops(s->blk, &virtio_block_ops, s); 970 blk_set_guest_block_size(s->blk, s->conf.conf.logical_block_size); 971 972 blk_iostatus_enable(s->blk); 973 } 974 975 static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp) 976 { 977 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 978 VirtIOBlock *s = VIRTIO_BLK(dev); 979 980 virtio_blk_data_plane_destroy(s->dataplane); 981 s->dataplane = NULL; 982 qemu_del_vm_change_state_handler(s->change); 983 blockdev_mark_auto_del(s->blk); 984 virtio_cleanup(vdev); 985 } 986 987 static void virtio_blk_instance_init(Object *obj) 988 { 989 VirtIOBlock *s = VIRTIO_BLK(obj); 990 991 device_add_bootindex_property(obj, &s->conf.conf.bootindex, 992 "bootindex", "/disk@0,0", 993 DEVICE(obj), NULL); 994 } 995 996 static const VMStateDescription vmstate_virtio_blk = { 997 .name = "virtio-blk", 998 .minimum_version_id = 2, 999 .version_id = 2, 1000 .fields = (VMStateField[]) { 1001 VMSTATE_VIRTIO_DEVICE, 1002 VMSTATE_END_OF_LIST() 1003 }, 1004 }; 1005 1006 static Property virtio_blk_properties[] = { 1007 DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf), 1008 DEFINE_BLOCK_ERROR_PROPERTIES(VirtIOBlock, conf.conf), 1009 DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, conf.conf), 1010 DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial), 1011 DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true), 1012 #ifdef __linux__ 1013 DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, false), 1014 #endif 1015 DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, 1016 true), 1017 DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1), 1018 DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128), 1019 DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD, 1020 IOThread *), 1021 DEFINE_PROP_END_OF_LIST(), 1022 }; 1023 1024 static void virtio_blk_class_init(ObjectClass *klass, void *data) 1025 { 1026 DeviceClass *dc = DEVICE_CLASS(klass); 1027 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 1028 1029 dc->props = virtio_blk_properties; 1030 dc->vmsd = &vmstate_virtio_blk; 1031 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories); 1032 vdc->realize = virtio_blk_device_realize; 1033 vdc->unrealize = virtio_blk_device_unrealize; 1034 vdc->get_config = virtio_blk_update_config; 1035 vdc->set_config = virtio_blk_set_config; 1036 vdc->get_features = virtio_blk_get_features; 1037 vdc->set_status = virtio_blk_set_status; 1038 vdc->reset = virtio_blk_reset; 1039 vdc->save = virtio_blk_save_device; 1040 vdc->load = virtio_blk_load_device; 1041 vdc->start_ioeventfd = virtio_blk_data_plane_start; 1042 vdc->stop_ioeventfd = virtio_blk_data_plane_stop; 1043 } 1044 1045 static const TypeInfo virtio_blk_info = { 1046 .name = TYPE_VIRTIO_BLK, 1047 .parent = TYPE_VIRTIO_DEVICE, 1048 .instance_size = sizeof(VirtIOBlock), 1049 .instance_init = virtio_blk_instance_init, 1050 .class_init = virtio_blk_class_init, 1051 }; 1052 1053 static void virtio_register_types(void) 1054 { 1055 type_register_static(&virtio_blk_info); 1056 } 1057 1058 type_init(virtio_register_types) 1059