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