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 /* We don't support discard yet, hide associated config fields. */ 32 #define VIRTIO_BLK_CFG_SIZE offsetof(struct virtio_blk_config, \ 33 max_discard_sectors) 34 35 static void virtio_blk_init_request(VirtIOBlock *s, VirtQueue *vq, 36 VirtIOBlockReq *req) 37 { 38 req->dev = s; 39 req->vq = vq; 40 req->qiov.size = 0; 41 req->in_len = 0; 42 req->next = NULL; 43 req->mr_next = NULL; 44 } 45 46 static void virtio_blk_free_request(VirtIOBlockReq *req) 47 { 48 g_free(req); 49 } 50 51 static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) 52 { 53 VirtIOBlock *s = req->dev; 54 VirtIODevice *vdev = VIRTIO_DEVICE(s); 55 56 trace_virtio_blk_req_complete(vdev, req, status); 57 58 stb_p(&req->in->status, status); 59 virtqueue_push(req->vq, &req->elem, req->in_len); 60 if (s->dataplane_started && !s->dataplane_disabled) { 61 virtio_blk_data_plane_notify(s->dataplane, req->vq); 62 } else { 63 virtio_notify(vdev, req->vq); 64 } 65 } 66 67 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, 68 bool is_read, bool acct_failed) 69 { 70 VirtIOBlock *s = req->dev; 71 BlockErrorAction action = blk_get_error_action(s->blk, is_read, error); 72 73 if (action == BLOCK_ERROR_ACTION_STOP) { 74 /* Break the link as the next request is going to be parsed from the 75 * ring again. Otherwise we may end up doing a double completion! */ 76 req->mr_next = NULL; 77 req->next = s->rq; 78 s->rq = req; 79 } else if (action == BLOCK_ERROR_ACTION_REPORT) { 80 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 81 if (acct_failed) { 82 block_acct_failed(blk_get_stats(s->blk), &req->acct); 83 } 84 virtio_blk_free_request(req); 85 } 86 87 blk_error_action(s->blk, action, is_read, error); 88 return action != BLOCK_ERROR_ACTION_IGNORE; 89 } 90 91 static void virtio_blk_rw_complete(void *opaque, int ret) 92 { 93 VirtIOBlockReq *next = opaque; 94 VirtIOBlock *s = next->dev; 95 VirtIODevice *vdev = VIRTIO_DEVICE(s); 96 97 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 98 while (next) { 99 VirtIOBlockReq *req = next; 100 next = req->mr_next; 101 trace_virtio_blk_rw_complete(vdev, req, ret); 102 103 if (req->qiov.nalloc != -1) { 104 /* If nalloc is != -1 req->qiov is a local copy of the original 105 * external iovec. It was allocated in submit_requests to be 106 * able to merge requests. */ 107 qemu_iovec_destroy(&req->qiov); 108 } 109 110 if (ret) { 111 int p = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); 112 bool is_read = !(p & VIRTIO_BLK_T_OUT); 113 /* Note that memory may be dirtied on read failure. If the 114 * virtio request is not completed here, as is the case for 115 * BLOCK_ERROR_ACTION_STOP, the memory may not be copied 116 * correctly during live migration. While this is ugly, 117 * it is acceptable because the device is free to write to 118 * the memory until the request is completed (which will 119 * happen on the other side of the migration). 120 */ 121 if (virtio_blk_handle_rw_error(req, -ret, is_read, true)) { 122 continue; 123 } 124 } 125 126 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 127 block_acct_done(blk_get_stats(req->dev->blk), &req->acct); 128 virtio_blk_free_request(req); 129 } 130 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 131 } 132 133 static void virtio_blk_flush_complete(void *opaque, int ret) 134 { 135 VirtIOBlockReq *req = opaque; 136 VirtIOBlock *s = req->dev; 137 138 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 139 if (ret) { 140 if (virtio_blk_handle_rw_error(req, -ret, 0, true)) { 141 goto out; 142 } 143 } 144 145 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 146 block_acct_done(blk_get_stats(s->blk), &req->acct); 147 virtio_blk_free_request(req); 148 149 out: 150 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 151 } 152 153 #ifdef __linux__ 154 155 typedef struct { 156 VirtIOBlockReq *req; 157 struct sg_io_hdr hdr; 158 } VirtIOBlockIoctlReq; 159 160 static void virtio_blk_ioctl_complete(void *opaque, int status) 161 { 162 VirtIOBlockIoctlReq *ioctl_req = opaque; 163 VirtIOBlockReq *req = ioctl_req->req; 164 VirtIOBlock *s = req->dev; 165 VirtIODevice *vdev = VIRTIO_DEVICE(s); 166 struct virtio_scsi_inhdr *scsi; 167 struct sg_io_hdr *hdr; 168 169 scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; 170 171 if (status) { 172 status = VIRTIO_BLK_S_UNSUPP; 173 virtio_stl_p(vdev, &scsi->errors, 255); 174 goto out; 175 } 176 177 hdr = &ioctl_req->hdr; 178 /* 179 * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi) 180 * clear the masked_status field [hence status gets cleared too, see 181 * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED 182 * status has occurred. However they do set DRIVER_SENSE in driver_status 183 * field. Also a (sb_len_wr > 0) indicates there is a sense buffer. 184 */ 185 if (hdr->status == 0 && hdr->sb_len_wr > 0) { 186 hdr->status = CHECK_CONDITION; 187 } 188 189 virtio_stl_p(vdev, &scsi->errors, 190 hdr->status | (hdr->msg_status << 8) | 191 (hdr->host_status << 16) | (hdr->driver_status << 24)); 192 virtio_stl_p(vdev, &scsi->residual, hdr->resid); 193 virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr); 194 virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len); 195 196 out: 197 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 198 virtio_blk_req_complete(req, status); 199 virtio_blk_free_request(req); 200 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 201 g_free(ioctl_req); 202 } 203 204 #endif 205 206 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s, VirtQueue *vq) 207 { 208 VirtIOBlockReq *req = virtqueue_pop(vq, sizeof(VirtIOBlockReq)); 209 210 if (req) { 211 virtio_blk_init_request(s, vq, req); 212 } 213 return req; 214 } 215 216 static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) 217 { 218 int status = VIRTIO_BLK_S_OK; 219 struct virtio_scsi_inhdr *scsi = NULL; 220 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); 221 VirtQueueElement *elem = &req->elem; 222 VirtIOBlock *blk = req->dev; 223 224 #ifdef __linux__ 225 int i; 226 VirtIOBlockIoctlReq *ioctl_req; 227 BlockAIOCB *acb; 228 #endif 229 230 /* 231 * We require at least one output segment each for the virtio_blk_outhdr 232 * and the SCSI command block. 233 * 234 * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr 235 * and the sense buffer pointer in the input segments. 236 */ 237 if (elem->out_num < 2 || elem->in_num < 3) { 238 status = VIRTIO_BLK_S_IOERR; 239 goto fail; 240 } 241 242 /* 243 * The scsi inhdr is placed in the second-to-last input segment, just 244 * before the regular inhdr. 245 */ 246 scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base; 247 248 if (!virtio_has_feature(blk->host_features, VIRTIO_BLK_F_SCSI)) { 249 status = VIRTIO_BLK_S_UNSUPP; 250 goto fail; 251 } 252 253 /* 254 * No support for bidirection commands yet. 255 */ 256 if (elem->out_num > 2 && elem->in_num > 3) { 257 status = VIRTIO_BLK_S_UNSUPP; 258 goto fail; 259 } 260 261 #ifdef __linux__ 262 ioctl_req = g_new0(VirtIOBlockIoctlReq, 1); 263 ioctl_req->req = req; 264 ioctl_req->hdr.interface_id = 'S'; 265 ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len; 266 ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base; 267 ioctl_req->hdr.dxfer_len = 0; 268 269 if (elem->out_num > 2) { 270 /* 271 * If there are more than the minimally required 2 output segments 272 * there is write payload starting from the third iovec. 273 */ 274 ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV; 275 ioctl_req->hdr.iovec_count = elem->out_num - 2; 276 277 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 278 ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len; 279 } 280 281 ioctl_req->hdr.dxferp = elem->out_sg + 2; 282 283 } else if (elem->in_num > 3) { 284 /* 285 * If we have more than 3 input segments the guest wants to actually 286 * read data. 287 */ 288 ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV; 289 ioctl_req->hdr.iovec_count = elem->in_num - 3; 290 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 291 ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len; 292 } 293 294 ioctl_req->hdr.dxferp = elem->in_sg; 295 } else { 296 /* 297 * Some SCSI commands don't actually transfer any data. 298 */ 299 ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE; 300 } 301 302 ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base; 303 ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len; 304 305 acb = blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr, 306 virtio_blk_ioctl_complete, ioctl_req); 307 if (!acb) { 308 g_free(ioctl_req); 309 status = VIRTIO_BLK_S_UNSUPP; 310 goto fail; 311 } 312 return -EINPROGRESS; 313 #else 314 abort(); 315 #endif 316 317 fail: 318 /* Just put anything nonzero so that the ioctl fails in the guest. */ 319 if (scsi) { 320 virtio_stl_p(vdev, &scsi->errors, 255); 321 } 322 return status; 323 } 324 325 static void virtio_blk_handle_scsi(VirtIOBlockReq *req) 326 { 327 int status; 328 329 status = virtio_blk_handle_scsi_req(req); 330 if (status != -EINPROGRESS) { 331 virtio_blk_req_complete(req, status); 332 virtio_blk_free_request(req); 333 } 334 } 335 336 static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb, 337 int start, int num_reqs, int niov) 338 { 339 QEMUIOVector *qiov = &mrb->reqs[start]->qiov; 340 int64_t sector_num = mrb->reqs[start]->sector_num; 341 bool is_write = mrb->is_write; 342 343 if (num_reqs > 1) { 344 int i; 345 struct iovec *tmp_iov = qiov->iov; 346 int tmp_niov = qiov->niov; 347 348 /* mrb->reqs[start]->qiov was initialized from external so we can't 349 * modify it here. We need to initialize it locally and then add the 350 * external iovecs. */ 351 qemu_iovec_init(qiov, niov); 352 353 for (i = 0; i < tmp_niov; i++) { 354 qemu_iovec_add(qiov, tmp_iov[i].iov_base, tmp_iov[i].iov_len); 355 } 356 357 for (i = start + 1; i < start + num_reqs; i++) { 358 qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0, 359 mrb->reqs[i]->qiov.size); 360 mrb->reqs[i - 1]->mr_next = mrb->reqs[i]; 361 } 362 363 trace_virtio_blk_submit_multireq(VIRTIO_DEVICE(mrb->reqs[start]->dev), 364 mrb, start, num_reqs, 365 sector_num << BDRV_SECTOR_BITS, 366 qiov->size, is_write); 367 block_acct_merge_done(blk_get_stats(blk), 368 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ, 369 num_reqs - 1); 370 } 371 372 if (is_write) { 373 blk_aio_pwritev(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0, 374 virtio_blk_rw_complete, mrb->reqs[start]); 375 } else { 376 blk_aio_preadv(blk, sector_num << BDRV_SECTOR_BITS, qiov, 0, 377 virtio_blk_rw_complete, mrb->reqs[start]); 378 } 379 } 380 381 static int multireq_compare(const void *a, const void *b) 382 { 383 const VirtIOBlockReq *req1 = *(VirtIOBlockReq **)a, 384 *req2 = *(VirtIOBlockReq **)b; 385 386 /* 387 * Note that we can't simply subtract sector_num1 from sector_num2 388 * here as that could overflow the return value. 389 */ 390 if (req1->sector_num > req2->sector_num) { 391 return 1; 392 } else if (req1->sector_num < req2->sector_num) { 393 return -1; 394 } else { 395 return 0; 396 } 397 } 398 399 static void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) 400 { 401 int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0; 402 uint32_t max_transfer; 403 int64_t sector_num = 0; 404 405 if (mrb->num_reqs == 1) { 406 submit_requests(blk, mrb, 0, 1, -1); 407 mrb->num_reqs = 0; 408 return; 409 } 410 411 max_transfer = blk_get_max_transfer(mrb->reqs[0]->dev->blk); 412 413 qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs), 414 &multireq_compare); 415 416 for (i = 0; i < mrb->num_reqs; i++) { 417 VirtIOBlockReq *req = mrb->reqs[i]; 418 if (num_reqs > 0) { 419 /* 420 * NOTE: We cannot merge the requests in below situations: 421 * 1. requests are not sequential 422 * 2. merge would exceed maximum number of IOVs 423 * 3. merge would exceed maximum transfer length of backend device 424 */ 425 if (sector_num + nb_sectors != req->sector_num || 426 niov > blk_get_max_iov(blk) - req->qiov.niov || 427 req->qiov.size > max_transfer || 428 nb_sectors > (max_transfer - 429 req->qiov.size) / BDRV_SECTOR_SIZE) { 430 submit_requests(blk, mrb, start, num_reqs, niov); 431 num_reqs = 0; 432 } 433 } 434 435 if (num_reqs == 0) { 436 sector_num = req->sector_num; 437 nb_sectors = niov = 0; 438 start = i; 439 } 440 441 nb_sectors += req->qiov.size / BDRV_SECTOR_SIZE; 442 niov += req->qiov.niov; 443 num_reqs++; 444 } 445 446 submit_requests(blk, mrb, start, num_reqs, niov); 447 mrb->num_reqs = 0; 448 } 449 450 static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb) 451 { 452 block_acct_start(blk_get_stats(req->dev->blk), &req->acct, 0, 453 BLOCK_ACCT_FLUSH); 454 455 /* 456 * Make sure all outstanding writes are posted to the backing device. 457 */ 458 if (mrb->is_write && mrb->num_reqs > 0) { 459 virtio_blk_submit_multireq(req->dev->blk, mrb); 460 } 461 blk_aio_flush(req->dev->blk, virtio_blk_flush_complete, req); 462 } 463 464 static bool virtio_blk_sect_range_ok(VirtIOBlock *dev, 465 uint64_t sector, size_t size) 466 { 467 uint64_t nb_sectors = size >> BDRV_SECTOR_BITS; 468 uint64_t total_sectors; 469 470 if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) { 471 return false; 472 } 473 if (sector & dev->sector_mask) { 474 return false; 475 } 476 if (size % dev->conf.conf.logical_block_size) { 477 return false; 478 } 479 blk_get_geometry(dev->blk, &total_sectors); 480 if (sector > total_sectors || nb_sectors > total_sectors - sector) { 481 return false; 482 } 483 return true; 484 } 485 486 static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) 487 { 488 uint32_t type; 489 struct iovec *in_iov = req->elem.in_sg; 490 struct iovec *out_iov = req->elem.out_sg; 491 unsigned in_num = req->elem.in_num; 492 unsigned out_num = req->elem.out_num; 493 VirtIOBlock *s = req->dev; 494 VirtIODevice *vdev = VIRTIO_DEVICE(s); 495 496 if (req->elem.out_num < 1 || req->elem.in_num < 1) { 497 virtio_error(vdev, "virtio-blk missing headers"); 498 return -1; 499 } 500 501 if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out, 502 sizeof(req->out)) != sizeof(req->out))) { 503 virtio_error(vdev, "virtio-blk request outhdr too short"); 504 return -1; 505 } 506 507 iov_discard_front(&out_iov, &out_num, sizeof(req->out)); 508 509 if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { 510 virtio_error(vdev, "virtio-blk request inhdr too short"); 511 return -1; 512 } 513 514 /* We always touch the last byte, so just see how big in_iov is. */ 515 req->in_len = iov_size(in_iov, in_num); 516 req->in = (void *)in_iov[in_num - 1].iov_base 517 + in_iov[in_num - 1].iov_len 518 - sizeof(struct virtio_blk_inhdr); 519 iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); 520 521 type = virtio_ldl_p(vdev, &req->out.type); 522 523 /* VIRTIO_BLK_T_OUT defines the command direction. VIRTIO_BLK_T_BARRIER 524 * is an optional flag. Although a guest should not send this flag if 525 * not negotiated we ignored it in the past. So keep ignoring it. */ 526 switch (type & ~(VIRTIO_BLK_T_OUT | VIRTIO_BLK_T_BARRIER)) { 527 case VIRTIO_BLK_T_IN: 528 { 529 bool is_write = type & VIRTIO_BLK_T_OUT; 530 req->sector_num = virtio_ldq_p(vdev, &req->out.sector); 531 532 if (is_write) { 533 qemu_iovec_init_external(&req->qiov, out_iov, out_num); 534 trace_virtio_blk_handle_write(vdev, req, req->sector_num, 535 req->qiov.size / BDRV_SECTOR_SIZE); 536 } else { 537 qemu_iovec_init_external(&req->qiov, in_iov, in_num); 538 trace_virtio_blk_handle_read(vdev, req, req->sector_num, 539 req->qiov.size / BDRV_SECTOR_SIZE); 540 } 541 542 if (!virtio_blk_sect_range_ok(s, req->sector_num, req->qiov.size)) { 543 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 544 block_acct_invalid(blk_get_stats(s->blk), 545 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 546 virtio_blk_free_request(req); 547 return 0; 548 } 549 550 block_acct_start(blk_get_stats(s->blk), &req->acct, req->qiov.size, 551 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 552 553 /* merge would exceed maximum number of requests or IO direction 554 * changes */ 555 if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS || 556 is_write != mrb->is_write || 557 !s->conf.request_merging)) { 558 virtio_blk_submit_multireq(s->blk, mrb); 559 } 560 561 assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS); 562 mrb->reqs[mrb->num_reqs++] = req; 563 mrb->is_write = is_write; 564 break; 565 } 566 case VIRTIO_BLK_T_FLUSH: 567 virtio_blk_handle_flush(req, mrb); 568 break; 569 case VIRTIO_BLK_T_SCSI_CMD: 570 virtio_blk_handle_scsi(req); 571 break; 572 case VIRTIO_BLK_T_GET_ID: 573 { 574 /* 575 * NB: per existing s/n string convention the string is 576 * terminated by '\0' only when shorter than buffer. 577 */ 578 const char *serial = s->conf.serial ? s->conf.serial : ""; 579 size_t size = MIN(strlen(serial) + 1, 580 MIN(iov_size(in_iov, in_num), 581 VIRTIO_BLK_ID_BYTES)); 582 iov_from_buf(in_iov, in_num, 0, serial, size); 583 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 584 virtio_blk_free_request(req); 585 break; 586 } 587 default: 588 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); 589 virtio_blk_free_request(req); 590 } 591 return 0; 592 } 593 594 bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq) 595 { 596 VirtIOBlockReq *req; 597 MultiReqBuffer mrb = {}; 598 bool progress = false; 599 600 aio_context_acquire(blk_get_aio_context(s->blk)); 601 blk_io_plug(s->blk); 602 603 do { 604 virtio_queue_set_notification(vq, 0); 605 606 while ((req = virtio_blk_get_request(s, vq))) { 607 progress = true; 608 if (virtio_blk_handle_request(req, &mrb)) { 609 virtqueue_detach_element(req->vq, &req->elem, 0); 610 virtio_blk_free_request(req); 611 break; 612 } 613 } 614 615 virtio_queue_set_notification(vq, 1); 616 } while (!virtio_queue_empty(vq)); 617 618 if (mrb.num_reqs) { 619 virtio_blk_submit_multireq(s->blk, &mrb); 620 } 621 622 blk_io_unplug(s->blk); 623 aio_context_release(blk_get_aio_context(s->blk)); 624 return progress; 625 } 626 627 static void virtio_blk_handle_output_do(VirtIOBlock *s, VirtQueue *vq) 628 { 629 virtio_blk_handle_vq(s, vq); 630 } 631 632 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) 633 { 634 VirtIOBlock *s = (VirtIOBlock *)vdev; 635 636 if (s->dataplane) { 637 /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start 638 * dataplane here instead of waiting for .set_status(). 639 */ 640 virtio_device_start_ioeventfd(vdev); 641 if (!s->dataplane_disabled) { 642 return; 643 } 644 } 645 virtio_blk_handle_output_do(s, vq); 646 } 647 648 static void virtio_blk_dma_restart_bh(void *opaque) 649 { 650 VirtIOBlock *s = opaque; 651 VirtIOBlockReq *req = s->rq; 652 MultiReqBuffer mrb = {}; 653 654 qemu_bh_delete(s->bh); 655 s->bh = NULL; 656 657 s->rq = NULL; 658 659 aio_context_acquire(blk_get_aio_context(s->conf.conf.blk)); 660 while (req) { 661 VirtIOBlockReq *next = req->next; 662 if (virtio_blk_handle_request(req, &mrb)) { 663 /* Device is now broken and won't do any processing until it gets 664 * reset. Already queued requests will be lost: let's purge them. 665 */ 666 while (req) { 667 next = req->next; 668 virtqueue_detach_element(req->vq, &req->elem, 0); 669 virtio_blk_free_request(req); 670 req = next; 671 } 672 break; 673 } 674 req = next; 675 } 676 677 if (mrb.num_reqs) { 678 virtio_blk_submit_multireq(s->blk, &mrb); 679 } 680 aio_context_release(blk_get_aio_context(s->conf.conf.blk)); 681 } 682 683 static void virtio_blk_dma_restart_cb(void *opaque, int running, 684 RunState state) 685 { 686 VirtIOBlock *s = opaque; 687 688 if (!running) { 689 return; 690 } 691 692 if (!s->bh) { 693 s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk), 694 virtio_blk_dma_restart_bh, s); 695 qemu_bh_schedule(s->bh); 696 } 697 } 698 699 static void virtio_blk_reset(VirtIODevice *vdev) 700 { 701 VirtIOBlock *s = VIRTIO_BLK(vdev); 702 AioContext *ctx; 703 VirtIOBlockReq *req; 704 705 ctx = blk_get_aio_context(s->blk); 706 aio_context_acquire(ctx); 707 blk_drain(s->blk); 708 709 /* We drop queued requests after blk_drain() because blk_drain() itself can 710 * produce them. */ 711 while (s->rq) { 712 req = s->rq; 713 s->rq = req->next; 714 virtqueue_detach_element(req->vq, &req->elem, 0); 715 virtio_blk_free_request(req); 716 } 717 718 aio_context_release(ctx); 719 720 assert(!s->dataplane_started); 721 blk_set_enable_write_cache(s->blk, s->original_wce); 722 } 723 724 /* coalesce internal state, copy to pci i/o region 0 725 */ 726 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) 727 { 728 VirtIOBlock *s = VIRTIO_BLK(vdev); 729 BlockConf *conf = &s->conf.conf; 730 struct virtio_blk_config blkcfg; 731 uint64_t capacity; 732 int64_t length; 733 int blk_size = conf->logical_block_size; 734 735 blk_get_geometry(s->blk, &capacity); 736 memset(&blkcfg, 0, sizeof(blkcfg)); 737 virtio_stq_p(vdev, &blkcfg.capacity, capacity); 738 virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); 739 virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls); 740 virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); 741 virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); 742 virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size); 743 blkcfg.geometry.heads = conf->heads; 744 /* 745 * We must ensure that the block device capacity is a multiple of 746 * the logical block size. If that is not the case, let's use 747 * sector_mask to adopt the geometry to have a correct picture. 748 * For those devices where the capacity is ok for the given geometry 749 * we don't touch the sector value of the geometry, since some devices 750 * (like s390 dasd) need a specific value. Here the capacity is already 751 * cyls*heads*secs*blk_size and the sector value is not block size 752 * divided by 512 - instead it is the amount of blk_size blocks 753 * per track (cylinder). 754 */ 755 length = blk_getlength(s->blk); 756 if (length > 0 && length / conf->heads / conf->secs % blk_size) { 757 blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; 758 } else { 759 blkcfg.geometry.sectors = conf->secs; 760 } 761 blkcfg.size_max = 0; 762 blkcfg.physical_block_exp = get_physical_block_exp(conf); 763 blkcfg.alignment_offset = 0; 764 blkcfg.wce = blk_enable_write_cache(s->blk); 765 virtio_stw_p(vdev, &blkcfg.num_queues, s->conf.num_queues); 766 memcpy(config, &blkcfg, VIRTIO_BLK_CFG_SIZE); 767 QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); 768 } 769 770 static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) 771 { 772 VirtIOBlock *s = VIRTIO_BLK(vdev); 773 struct virtio_blk_config blkcfg; 774 775 memcpy(&blkcfg, config, VIRTIO_BLK_CFG_SIZE); 776 QEMU_BUILD_BUG_ON(VIRTIO_BLK_CFG_SIZE > sizeof(blkcfg)); 777 778 aio_context_acquire(blk_get_aio_context(s->blk)); 779 blk_set_enable_write_cache(s->blk, blkcfg.wce != 0); 780 aio_context_release(blk_get_aio_context(s->blk)); 781 } 782 783 static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, 784 Error **errp) 785 { 786 VirtIOBlock *s = VIRTIO_BLK(vdev); 787 788 /* Firstly sync all virtio-blk possible supported features */ 789 features |= s->host_features; 790 791 virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX); 792 virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY); 793 virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY); 794 virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE); 795 if (virtio_has_feature(features, VIRTIO_F_VERSION_1)) { 796 if (virtio_has_feature(s->host_features, VIRTIO_BLK_F_SCSI)) { 797 error_setg(errp, "Please set scsi=off for virtio-blk devices in order to use virtio 1.0"); 798 return 0; 799 } 800 } else { 801 virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT); 802 virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); 803 } 804 805 if (blk_enable_write_cache(s->blk)) { 806 virtio_add_feature(&features, VIRTIO_BLK_F_WCE); 807 } 808 if (blk_is_read_only(s->blk)) { 809 virtio_add_feature(&features, VIRTIO_BLK_F_RO); 810 } 811 if (s->conf.num_queues > 1) { 812 virtio_add_feature(&features, VIRTIO_BLK_F_MQ); 813 } 814 815 return features; 816 } 817 818 static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status) 819 { 820 VirtIOBlock *s = VIRTIO_BLK(vdev); 821 822 if (!(status & (VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK))) { 823 assert(!s->dataplane_started); 824 } 825 826 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) { 827 return; 828 } 829 830 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send 831 * cache flushes. Thus, the "auto writethrough" behavior is never 832 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature. 833 * Leaving it enabled would break the following sequence: 834 * 835 * Guest started with "-drive cache=writethrough" 836 * Guest sets status to 0 837 * Guest sets DRIVER bit in status field 838 * Guest reads host features (WCE=0, CONFIG_WCE=1) 839 * Guest writes guest features (WCE=0, CONFIG_WCE=1) 840 * Guest writes 1 to the WCE configuration field (writeback mode) 841 * Guest sets DRIVER_OK bit in status field 842 * 843 * s->blk would erroneously be placed in writethrough mode. 844 */ 845 if (!virtio_vdev_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) { 846 aio_context_acquire(blk_get_aio_context(s->blk)); 847 blk_set_enable_write_cache(s->blk, 848 virtio_vdev_has_feature(vdev, 849 VIRTIO_BLK_F_WCE)); 850 aio_context_release(blk_get_aio_context(s->blk)); 851 } 852 } 853 854 static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f) 855 { 856 VirtIOBlock *s = VIRTIO_BLK(vdev); 857 VirtIOBlockReq *req = s->rq; 858 859 while (req) { 860 qemu_put_sbyte(f, 1); 861 862 if (s->conf.num_queues > 1) { 863 qemu_put_be32(f, virtio_get_queue_index(req->vq)); 864 } 865 866 qemu_put_virtqueue_element(f, &req->elem); 867 req = req->next; 868 } 869 qemu_put_sbyte(f, 0); 870 } 871 872 static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f, 873 int version_id) 874 { 875 VirtIOBlock *s = VIRTIO_BLK(vdev); 876 877 while (qemu_get_sbyte(f)) { 878 unsigned nvqs = s->conf.num_queues; 879 unsigned vq_idx = 0; 880 VirtIOBlockReq *req; 881 882 if (nvqs > 1) { 883 vq_idx = qemu_get_be32(f); 884 885 if (vq_idx >= nvqs) { 886 error_report("Invalid virtqueue index in request list: %#x", 887 vq_idx); 888 return -EINVAL; 889 } 890 } 891 892 req = qemu_get_virtqueue_element(vdev, f, sizeof(VirtIOBlockReq)); 893 virtio_blk_init_request(s, virtio_get_queue(vdev, vq_idx), req); 894 req->next = s->rq; 895 s->rq = req; 896 } 897 898 return 0; 899 } 900 901 static void virtio_blk_resize(void *opaque) 902 { 903 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 904 905 virtio_notify_config(vdev); 906 } 907 908 static const BlockDevOps virtio_block_ops = { 909 .resize_cb = virtio_blk_resize, 910 }; 911 912 static void virtio_blk_device_realize(DeviceState *dev, Error **errp) 913 { 914 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 915 VirtIOBlock *s = VIRTIO_BLK(dev); 916 VirtIOBlkConf *conf = &s->conf; 917 Error *err = NULL; 918 unsigned i; 919 920 if (!conf->conf.blk) { 921 error_setg(errp, "drive property not set"); 922 return; 923 } 924 if (!blk_is_inserted(conf->conf.blk)) { 925 error_setg(errp, "Device needs media, but drive is empty"); 926 return; 927 } 928 if (!conf->num_queues) { 929 error_setg(errp, "num-queues property must be larger than 0"); 930 return; 931 } 932 if (!is_power_of_2(conf->queue_size) || 933 conf->queue_size > VIRTQUEUE_MAX_SIZE) { 934 error_setg(errp, "invalid queue-size property (%" PRIu16 "), " 935 "must be a power of 2 (max %d)", 936 conf->queue_size, VIRTQUEUE_MAX_SIZE); 937 return; 938 } 939 940 if (!blkconf_apply_backend_options(&conf->conf, 941 blk_is_read_only(conf->conf.blk), true, 942 errp)) { 943 return; 944 } 945 s->original_wce = blk_enable_write_cache(conf->conf.blk); 946 if (!blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, errp)) { 947 return; 948 } 949 950 blkconf_blocksizes(&conf->conf); 951 952 if (conf->conf.logical_block_size > 953 conf->conf.physical_block_size) { 954 error_setg(errp, 955 "logical_block_size > physical_block_size not supported"); 956 return; 957 } 958 959 virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, VIRTIO_BLK_CFG_SIZE); 960 961 s->blk = conf->conf.blk; 962 s->rq = NULL; 963 s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1; 964 965 for (i = 0; i < conf->num_queues; i++) { 966 virtio_add_queue(vdev, conf->queue_size, virtio_blk_handle_output); 967 } 968 virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err); 969 if (err != NULL) { 970 error_propagate(errp, err); 971 virtio_cleanup(vdev); 972 return; 973 } 974 975 s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); 976 blk_set_dev_ops(s->blk, &virtio_block_ops, s); 977 blk_set_guest_block_size(s->blk, s->conf.conf.logical_block_size); 978 979 blk_iostatus_enable(s->blk); 980 } 981 982 static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp) 983 { 984 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 985 VirtIOBlock *s = VIRTIO_BLK(dev); 986 987 virtio_blk_data_plane_destroy(s->dataplane); 988 s->dataplane = NULL; 989 qemu_del_vm_change_state_handler(s->change); 990 blockdev_mark_auto_del(s->blk); 991 virtio_cleanup(vdev); 992 } 993 994 static void virtio_blk_instance_init(Object *obj) 995 { 996 VirtIOBlock *s = VIRTIO_BLK(obj); 997 998 device_add_bootindex_property(obj, &s->conf.conf.bootindex, 999 "bootindex", "/disk@0,0", 1000 DEVICE(obj), NULL); 1001 } 1002 1003 static const VMStateDescription vmstate_virtio_blk = { 1004 .name = "virtio-blk", 1005 .minimum_version_id = 2, 1006 .version_id = 2, 1007 .fields = (VMStateField[]) { 1008 VMSTATE_VIRTIO_DEVICE, 1009 VMSTATE_END_OF_LIST() 1010 }, 1011 }; 1012 1013 static Property virtio_blk_properties[] = { 1014 DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf), 1015 DEFINE_BLOCK_ERROR_PROPERTIES(VirtIOBlock, conf.conf), 1016 DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, conf.conf), 1017 DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial), 1018 DEFINE_PROP_BIT64("config-wce", VirtIOBlock, host_features, 1019 VIRTIO_BLK_F_CONFIG_WCE, true), 1020 #ifdef __linux__ 1021 DEFINE_PROP_BIT64("scsi", VirtIOBlock, host_features, 1022 VIRTIO_BLK_F_SCSI, false), 1023 #endif 1024 DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, 1025 true), 1026 DEFINE_PROP_UINT16("num-queues", VirtIOBlock, conf.num_queues, 1), 1027 DEFINE_PROP_UINT16("queue-size", VirtIOBlock, conf.queue_size, 128), 1028 DEFINE_PROP_LINK("iothread", VirtIOBlock, conf.iothread, TYPE_IOTHREAD, 1029 IOThread *), 1030 DEFINE_PROP_BIT64("discard", VirtIOBlock, host_features, 1031 VIRTIO_BLK_F_DISCARD, true), 1032 DEFINE_PROP_BIT64("write-zeroes", VirtIOBlock, host_features, 1033 VIRTIO_BLK_F_WRITE_ZEROES, true), 1034 DEFINE_PROP_END_OF_LIST(), 1035 }; 1036 1037 static void virtio_blk_class_init(ObjectClass *klass, void *data) 1038 { 1039 DeviceClass *dc = DEVICE_CLASS(klass); 1040 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 1041 1042 dc->props = virtio_blk_properties; 1043 dc->vmsd = &vmstate_virtio_blk; 1044 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories); 1045 vdc->realize = virtio_blk_device_realize; 1046 vdc->unrealize = virtio_blk_device_unrealize; 1047 vdc->get_config = virtio_blk_update_config; 1048 vdc->set_config = virtio_blk_set_config; 1049 vdc->get_features = virtio_blk_get_features; 1050 vdc->set_status = virtio_blk_set_status; 1051 vdc->reset = virtio_blk_reset; 1052 vdc->save = virtio_blk_save_device; 1053 vdc->load = virtio_blk_load_device; 1054 vdc->start_ioeventfd = virtio_blk_data_plane_start; 1055 vdc->stop_ioeventfd = virtio_blk_data_plane_stop; 1056 } 1057 1058 static const TypeInfo virtio_blk_info = { 1059 .name = TYPE_VIRTIO_BLK, 1060 .parent = TYPE_VIRTIO_DEVICE, 1061 .instance_size = sizeof(VirtIOBlock), 1062 .instance_init = virtio_blk_instance_init, 1063 .class_init = virtio_blk_class_init, 1064 }; 1065 1066 static void virtio_register_types(void) 1067 { 1068 type_register_static(&virtio_blk_info); 1069 } 1070 1071 type_init(virtio_register_types) 1072