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-common.h" 15 #include "qemu/iov.h" 16 #include "qemu/error-report.h" 17 #include "trace.h" 18 #include "hw/block/block.h" 19 #include "sysemu/block-backend.h" 20 #include "sysemu/blockdev.h" 21 #include "hw/virtio/virtio-blk.h" 22 #include "dataplane/virtio-blk.h" 23 #include "migration/migration.h" 24 #include "block/scsi.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 VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) 32 { 33 VirtIOBlockReq *req = g_new(VirtIOBlockReq, 1); 34 req->dev = s; 35 req->qiov.size = 0; 36 req->in_len = 0; 37 req->next = NULL; 38 req->mr_next = NULL; 39 return req; 40 } 41 42 void virtio_blk_free_request(VirtIOBlockReq *req) 43 { 44 if (req) { 45 g_free(req); 46 } 47 } 48 49 static void virtio_blk_complete_request(VirtIOBlockReq *req, 50 unsigned char status) 51 { 52 VirtIOBlock *s = req->dev; 53 VirtIODevice *vdev = VIRTIO_DEVICE(s); 54 55 trace_virtio_blk_req_complete(req, status); 56 57 stb_p(&req->in->status, status); 58 virtqueue_push(s->vq, &req->elem, req->in_len); 59 virtio_notify(vdev, s->vq); 60 } 61 62 static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status) 63 { 64 req->dev->complete_request(req, status); 65 } 66 67 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, 68 bool is_read) 69 { 70 BlockErrorAction action = blk_get_error_action(req->dev->blk, 71 is_read, error); 72 VirtIOBlock *s = req->dev; 73 74 if (action == BLOCK_ERROR_ACTION_STOP) { 75 req->next = s->rq; 76 s->rq = req; 77 } else if (action == BLOCK_ERROR_ACTION_REPORT) { 78 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 79 block_acct_failed(blk_get_stats(s->blk), &req->acct); 80 virtio_blk_free_request(req); 81 } 82 83 blk_error_action(s->blk, action, is_read, error); 84 return action != BLOCK_ERROR_ACTION_IGNORE; 85 } 86 87 static void virtio_blk_rw_complete(void *opaque, int ret) 88 { 89 VirtIOBlockReq *next = opaque; 90 91 while (next) { 92 VirtIOBlockReq *req = next; 93 next = req->mr_next; 94 trace_virtio_blk_rw_complete(req, ret); 95 96 if (req->qiov.nalloc != -1) { 97 /* If nalloc is != 1 req->qiov is a local copy of the original 98 * external iovec. It was allocated in submit_merged_requests 99 * to be able to merge requests. */ 100 qemu_iovec_destroy(&req->qiov); 101 } 102 103 if (ret) { 104 int p = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); 105 bool is_read = !(p & VIRTIO_BLK_T_OUT); 106 /* Note that memory may be dirtied on read failure. If the 107 * virtio request is not completed here, as is the case for 108 * BLOCK_ERROR_ACTION_STOP, the memory may not be copied 109 * correctly during live migration. While this is ugly, 110 * it is acceptable because the device is free to write to 111 * the memory until the request is completed (which will 112 * happen on the other side of the migration). 113 */ 114 if (virtio_blk_handle_rw_error(req, -ret, is_read)) { 115 continue; 116 } 117 } 118 119 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 120 block_acct_done(blk_get_stats(req->dev->blk), &req->acct); 121 virtio_blk_free_request(req); 122 } 123 } 124 125 static void virtio_blk_flush_complete(void *opaque, int ret) 126 { 127 VirtIOBlockReq *req = opaque; 128 129 if (ret) { 130 if (virtio_blk_handle_rw_error(req, -ret, 0)) { 131 return; 132 } 133 } 134 135 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 136 block_acct_done(blk_get_stats(req->dev->blk), &req->acct); 137 virtio_blk_free_request(req); 138 } 139 140 #ifdef __linux__ 141 142 typedef struct { 143 VirtIOBlockReq *req; 144 struct sg_io_hdr hdr; 145 } VirtIOBlockIoctlReq; 146 147 static void virtio_blk_ioctl_complete(void *opaque, int status) 148 { 149 VirtIOBlockIoctlReq *ioctl_req = opaque; 150 VirtIOBlockReq *req = ioctl_req->req; 151 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); 152 struct virtio_scsi_inhdr *scsi; 153 struct sg_io_hdr *hdr; 154 155 scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; 156 157 if (status) { 158 status = VIRTIO_BLK_S_UNSUPP; 159 virtio_stl_p(vdev, &scsi->errors, 255); 160 goto out; 161 } 162 163 hdr = &ioctl_req->hdr; 164 /* 165 * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi) 166 * clear the masked_status field [hence status gets cleared too, see 167 * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED 168 * status has occurred. However they do set DRIVER_SENSE in driver_status 169 * field. Also a (sb_len_wr > 0) indicates there is a sense buffer. 170 */ 171 if (hdr->status == 0 && hdr->sb_len_wr > 0) { 172 hdr->status = CHECK_CONDITION; 173 } 174 175 virtio_stl_p(vdev, &scsi->errors, 176 hdr->status | (hdr->msg_status << 8) | 177 (hdr->host_status << 16) | (hdr->driver_status << 24)); 178 virtio_stl_p(vdev, &scsi->residual, hdr->resid); 179 virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr); 180 virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len); 181 182 out: 183 virtio_blk_req_complete(req, status); 184 virtio_blk_free_request(req); 185 g_free(ioctl_req); 186 } 187 188 #endif 189 190 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s) 191 { 192 VirtIOBlockReq *req = virtio_blk_alloc_request(s); 193 194 if (!virtqueue_pop(s->vq, &req->elem)) { 195 virtio_blk_free_request(req); 196 return NULL; 197 } 198 199 return req; 200 } 201 202 static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req) 203 { 204 int status = VIRTIO_BLK_S_OK; 205 struct virtio_scsi_inhdr *scsi = NULL; 206 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev); 207 VirtQueueElement *elem = &req->elem; 208 VirtIOBlock *blk = req->dev; 209 210 #ifdef __linux__ 211 int i; 212 VirtIOBlockIoctlReq *ioctl_req; 213 BlockAIOCB *acb; 214 #endif 215 216 /* 217 * We require at least one output segment each for the virtio_blk_outhdr 218 * and the SCSI command block. 219 * 220 * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr 221 * and the sense buffer pointer in the input segments. 222 */ 223 if (elem->out_num < 2 || elem->in_num < 3) { 224 status = VIRTIO_BLK_S_IOERR; 225 goto fail; 226 } 227 228 /* 229 * The scsi inhdr is placed in the second-to-last input segment, just 230 * before the regular inhdr. 231 */ 232 scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base; 233 234 if (!blk->conf.scsi) { 235 status = VIRTIO_BLK_S_UNSUPP; 236 goto fail; 237 } 238 239 /* 240 * No support for bidirection commands yet. 241 */ 242 if (elem->out_num > 2 && elem->in_num > 3) { 243 status = VIRTIO_BLK_S_UNSUPP; 244 goto fail; 245 } 246 247 #ifdef __linux__ 248 ioctl_req = g_new0(VirtIOBlockIoctlReq, 1); 249 ioctl_req->req = req; 250 ioctl_req->hdr.interface_id = 'S'; 251 ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len; 252 ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base; 253 ioctl_req->hdr.dxfer_len = 0; 254 255 if (elem->out_num > 2) { 256 /* 257 * If there are more than the minimally required 2 output segments 258 * there is write payload starting from the third iovec. 259 */ 260 ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV; 261 ioctl_req->hdr.iovec_count = elem->out_num - 2; 262 263 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 264 ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len; 265 } 266 267 ioctl_req->hdr.dxferp = elem->out_sg + 2; 268 269 } else if (elem->in_num > 3) { 270 /* 271 * If we have more than 3 input segments the guest wants to actually 272 * read data. 273 */ 274 ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV; 275 ioctl_req->hdr.iovec_count = elem->in_num - 3; 276 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) { 277 ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len; 278 } 279 280 ioctl_req->hdr.dxferp = elem->in_sg; 281 } else { 282 /* 283 * Some SCSI commands don't actually transfer any data. 284 */ 285 ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE; 286 } 287 288 ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base; 289 ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len; 290 291 acb = blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr, 292 virtio_blk_ioctl_complete, ioctl_req); 293 if (!acb) { 294 g_free(ioctl_req); 295 status = VIRTIO_BLK_S_UNSUPP; 296 goto fail; 297 } 298 return -EINPROGRESS; 299 #else 300 abort(); 301 #endif 302 303 fail: 304 /* Just put anything nonzero so that the ioctl fails in the guest. */ 305 if (scsi) { 306 virtio_stl_p(vdev, &scsi->errors, 255); 307 } 308 return status; 309 } 310 311 static void virtio_blk_handle_scsi(VirtIOBlockReq *req) 312 { 313 int status; 314 315 status = virtio_blk_handle_scsi_req(req); 316 if (status != -EINPROGRESS) { 317 virtio_blk_req_complete(req, status); 318 virtio_blk_free_request(req); 319 } 320 } 321 322 static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb, 323 int start, int num_reqs, int niov) 324 { 325 QEMUIOVector *qiov = &mrb->reqs[start]->qiov; 326 int64_t sector_num = mrb->reqs[start]->sector_num; 327 int nb_sectors = mrb->reqs[start]->qiov.size / BDRV_SECTOR_SIZE; 328 bool is_write = mrb->is_write; 329 330 if (num_reqs > 1) { 331 int i; 332 struct iovec *tmp_iov = qiov->iov; 333 int tmp_niov = qiov->niov; 334 335 /* mrb->reqs[start]->qiov was initialized from external so we can't 336 * modifiy it here. We need to initialize it locally and then add the 337 * external iovecs. */ 338 qemu_iovec_init(qiov, niov); 339 340 for (i = 0; i < tmp_niov; i++) { 341 qemu_iovec_add(qiov, tmp_iov[i].iov_base, tmp_iov[i].iov_len); 342 } 343 344 for (i = start + 1; i < start + num_reqs; i++) { 345 qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0, 346 mrb->reqs[i]->qiov.size); 347 mrb->reqs[i - 1]->mr_next = mrb->reqs[i]; 348 nb_sectors += mrb->reqs[i]->qiov.size / BDRV_SECTOR_SIZE; 349 } 350 assert(nb_sectors == qiov->size / BDRV_SECTOR_SIZE); 351 352 trace_virtio_blk_submit_multireq(mrb, start, num_reqs, sector_num, 353 nb_sectors, is_write); 354 block_acct_merge_done(blk_get_stats(blk), 355 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ, 356 num_reqs - 1); 357 } 358 359 if (is_write) { 360 blk_aio_writev(blk, sector_num, qiov, nb_sectors, 361 virtio_blk_rw_complete, mrb->reqs[start]); 362 } else { 363 blk_aio_readv(blk, sector_num, qiov, nb_sectors, 364 virtio_blk_rw_complete, mrb->reqs[start]); 365 } 366 } 367 368 static int multireq_compare(const void *a, const void *b) 369 { 370 const VirtIOBlockReq *req1 = *(VirtIOBlockReq **)a, 371 *req2 = *(VirtIOBlockReq **)b; 372 373 /* 374 * Note that we can't simply subtract sector_num1 from sector_num2 375 * here as that could overflow the return value. 376 */ 377 if (req1->sector_num > req2->sector_num) { 378 return 1; 379 } else if (req1->sector_num < req2->sector_num) { 380 return -1; 381 } else { 382 return 0; 383 } 384 } 385 386 void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb) 387 { 388 int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0; 389 int max_xfer_len = 0; 390 int64_t sector_num = 0; 391 392 if (mrb->num_reqs == 1) { 393 submit_requests(blk, mrb, 0, 1, -1); 394 mrb->num_reqs = 0; 395 return; 396 } 397 398 max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk); 399 max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS); 400 401 qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs), 402 &multireq_compare); 403 404 for (i = 0; i < mrb->num_reqs; i++) { 405 VirtIOBlockReq *req = mrb->reqs[i]; 406 if (num_reqs > 0) { 407 bool merge = true; 408 409 /* merge would exceed maximum number of IOVs */ 410 if (niov + req->qiov.niov > IOV_MAX) { 411 merge = false; 412 } 413 414 /* merge would exceed maximum transfer length of backend device */ 415 if (req->qiov.size / BDRV_SECTOR_SIZE + nb_sectors > max_xfer_len) { 416 merge = false; 417 } 418 419 /* requests are not sequential */ 420 if (sector_num + nb_sectors != req->sector_num) { 421 merge = false; 422 } 423 424 if (!merge) { 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 void 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; 488 489 if (req->elem.out_num < 1 || req->elem.in_num < 1) { 490 error_report("virtio-blk missing headers"); 491 exit(1); 492 } 493 494 if (unlikely(iov_to_buf(iov, out_num, 0, &req->out, 495 sizeof(req->out)) != sizeof(req->out))) { 496 error_report("virtio-blk request outhdr too short"); 497 exit(1); 498 } 499 500 iov_discard_front(&iov, &out_num, sizeof(req->out)); 501 502 if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) { 503 error_report("virtio-blk request inhdr too short"); 504 exit(1); 505 } 506 507 /* We always touch the last byte, so just see how big in_iov is. */ 508 req->in_len = iov_size(in_iov, in_num); 509 req->in = (void *)in_iov[in_num - 1].iov_base 510 + in_iov[in_num - 1].iov_len 511 - sizeof(struct virtio_blk_inhdr); 512 iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr)); 513 514 type = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type); 515 516 /* VIRTIO_BLK_T_OUT defines the command direction. VIRTIO_BLK_T_BARRIER 517 * is an optional flag. Although a guest should not send this flag if 518 * not negotiated we ignored it in the past. So keep ignoring it. */ 519 switch (type & ~(VIRTIO_BLK_T_OUT | VIRTIO_BLK_T_BARRIER)) { 520 case VIRTIO_BLK_T_IN: 521 { 522 bool is_write = type & VIRTIO_BLK_T_OUT; 523 req->sector_num = virtio_ldq_p(VIRTIO_DEVICE(req->dev), 524 &req->out.sector); 525 526 if (is_write) { 527 qemu_iovec_init_external(&req->qiov, iov, out_num); 528 trace_virtio_blk_handle_write(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(req, req->sector_num, 533 req->qiov.size / BDRV_SECTOR_SIZE); 534 } 535 536 if (!virtio_blk_sect_range_ok(req->dev, req->sector_num, 537 req->qiov.size)) { 538 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); 539 block_acct_invalid(blk_get_stats(req->dev->blk), 540 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 541 virtio_blk_free_request(req); 542 return; 543 } 544 545 block_acct_start(blk_get_stats(req->dev->blk), 546 &req->acct, req->qiov.size, 547 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ); 548 549 /* merge would exceed maximum number of requests or IO direction 550 * changes */ 551 if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS || 552 is_write != mrb->is_write || 553 !req->dev->conf.request_merging)) { 554 virtio_blk_submit_multireq(req->dev->blk, mrb); 555 } 556 557 assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS); 558 mrb->reqs[mrb->num_reqs++] = req; 559 mrb->is_write = is_write; 560 break; 561 } 562 case VIRTIO_BLK_T_FLUSH: 563 virtio_blk_handle_flush(req, mrb); 564 break; 565 case VIRTIO_BLK_T_SCSI_CMD: 566 virtio_blk_handle_scsi(req); 567 break; 568 case VIRTIO_BLK_T_GET_ID: 569 { 570 VirtIOBlock *s = req->dev; 571 572 /* 573 * NB: per existing s/n string convention the string is 574 * terminated by '\0' only when shorter than buffer. 575 */ 576 const char *serial = s->conf.serial ? s->conf.serial : ""; 577 size_t size = MIN(strlen(serial) + 1, 578 MIN(iov_size(in_iov, in_num), 579 VIRTIO_BLK_ID_BYTES)); 580 iov_from_buf(in_iov, in_num, 0, serial, size); 581 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); 582 virtio_blk_free_request(req); 583 break; 584 } 585 default: 586 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); 587 virtio_blk_free_request(req); 588 } 589 } 590 591 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) 592 { 593 VirtIOBlock *s = VIRTIO_BLK(vdev); 594 VirtIOBlockReq *req; 595 MultiReqBuffer mrb = {}; 596 597 /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start 598 * dataplane here instead of waiting for .set_status(). 599 */ 600 if (s->dataplane) { 601 virtio_blk_data_plane_start(s->dataplane); 602 return; 603 } 604 605 blk_io_plug(s->blk); 606 607 while ((req = virtio_blk_get_request(s))) { 608 virtio_blk_handle_request(req, &mrb); 609 } 610 611 if (mrb.num_reqs) { 612 virtio_blk_submit_multireq(s->blk, &mrb); 613 } 614 615 blk_io_unplug(s->blk); 616 } 617 618 static void virtio_blk_dma_restart_bh(void *opaque) 619 { 620 VirtIOBlock *s = opaque; 621 VirtIOBlockReq *req = s->rq; 622 MultiReqBuffer mrb = {}; 623 624 qemu_bh_delete(s->bh); 625 s->bh = NULL; 626 627 s->rq = NULL; 628 629 while (req) { 630 VirtIOBlockReq *next = req->next; 631 virtio_blk_handle_request(req, &mrb); 632 req = next; 633 } 634 635 if (mrb.num_reqs) { 636 virtio_blk_submit_multireq(s->blk, &mrb); 637 } 638 } 639 640 static void virtio_blk_dma_restart_cb(void *opaque, int running, 641 RunState state) 642 { 643 VirtIOBlock *s = opaque; 644 645 if (!running) { 646 return; 647 } 648 649 if (!s->bh) { 650 s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk), 651 virtio_blk_dma_restart_bh, s); 652 qemu_bh_schedule(s->bh); 653 } 654 } 655 656 static void virtio_blk_reset(VirtIODevice *vdev) 657 { 658 VirtIOBlock *s = VIRTIO_BLK(vdev); 659 AioContext *ctx; 660 661 /* 662 * This should cancel pending requests, but can't do nicely until there 663 * are per-device request lists. 664 */ 665 ctx = blk_get_aio_context(s->blk); 666 aio_context_acquire(ctx); 667 blk_drain(s->blk); 668 669 if (s->dataplane) { 670 virtio_blk_data_plane_stop(s->dataplane); 671 } 672 aio_context_release(ctx); 673 674 blk_set_enable_write_cache(s->blk, s->original_wce); 675 } 676 677 /* coalesce internal state, copy to pci i/o region 0 678 */ 679 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) 680 { 681 VirtIOBlock *s = VIRTIO_BLK(vdev); 682 BlockConf *conf = &s->conf.conf; 683 struct virtio_blk_config blkcfg; 684 uint64_t capacity; 685 int blk_size = conf->logical_block_size; 686 687 blk_get_geometry(s->blk, &capacity); 688 memset(&blkcfg, 0, sizeof(blkcfg)); 689 virtio_stq_p(vdev, &blkcfg.capacity, capacity); 690 virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2); 691 virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls); 692 virtio_stl_p(vdev, &blkcfg.blk_size, blk_size); 693 virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size); 694 virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size); 695 blkcfg.geometry.heads = conf->heads; 696 /* 697 * We must ensure that the block device capacity is a multiple of 698 * the logical block size. If that is not the case, let's use 699 * sector_mask to adopt the geometry to have a correct picture. 700 * For those devices where the capacity is ok for the given geometry 701 * we don't touch the sector value of the geometry, since some devices 702 * (like s390 dasd) need a specific value. Here the capacity is already 703 * cyls*heads*secs*blk_size and the sector value is not block size 704 * divided by 512 - instead it is the amount of blk_size blocks 705 * per track (cylinder). 706 */ 707 if (blk_getlength(s->blk) / conf->heads / conf->secs % blk_size) { 708 blkcfg.geometry.sectors = conf->secs & ~s->sector_mask; 709 } else { 710 blkcfg.geometry.sectors = conf->secs; 711 } 712 blkcfg.size_max = 0; 713 blkcfg.physical_block_exp = get_physical_block_exp(conf); 714 blkcfg.alignment_offset = 0; 715 blkcfg.wce = blk_enable_write_cache(s->blk); 716 memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); 717 } 718 719 static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config) 720 { 721 VirtIOBlock *s = VIRTIO_BLK(vdev); 722 struct virtio_blk_config blkcfg; 723 724 memcpy(&blkcfg, config, sizeof(blkcfg)); 725 726 aio_context_acquire(blk_get_aio_context(s->blk)); 727 blk_set_enable_write_cache(s->blk, blkcfg.wce != 0); 728 aio_context_release(blk_get_aio_context(s->blk)); 729 } 730 731 static uint64_t virtio_blk_get_features(VirtIODevice *vdev, uint64_t features, 732 Error **errp) 733 { 734 VirtIOBlock *s = VIRTIO_BLK(vdev); 735 736 virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX); 737 virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY); 738 virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY); 739 virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE); 740 if (virtio_has_feature(features, VIRTIO_F_VERSION_1)) { 741 if (s->conf.scsi) { 742 error_setg(errp, "Please set scsi=off for virtio-blk devices in order to use virtio 1.0"); 743 return 0; 744 } 745 } else { 746 virtio_clear_feature(&features, VIRTIO_F_ANY_LAYOUT); 747 virtio_add_feature(&features, VIRTIO_BLK_F_SCSI); 748 } 749 750 if (s->conf.config_wce) { 751 virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE); 752 } 753 if (blk_enable_write_cache(s->blk)) { 754 virtio_add_feature(&features, VIRTIO_BLK_F_WCE); 755 } 756 if (blk_is_read_only(s->blk)) { 757 virtio_add_feature(&features, VIRTIO_BLK_F_RO); 758 } 759 760 return features; 761 } 762 763 static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status) 764 { 765 VirtIOBlock *s = VIRTIO_BLK(vdev); 766 767 if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER | 768 VIRTIO_CONFIG_S_DRIVER_OK))) { 769 virtio_blk_data_plane_stop(s->dataplane); 770 } 771 772 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) { 773 return; 774 } 775 776 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send 777 * cache flushes. Thus, the "auto writethrough" behavior is never 778 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature. 779 * Leaving it enabled would break the following sequence: 780 * 781 * Guest started with "-drive cache=writethrough" 782 * Guest sets status to 0 783 * Guest sets DRIVER bit in status field 784 * Guest reads host features (WCE=0, CONFIG_WCE=1) 785 * Guest writes guest features (WCE=0, CONFIG_WCE=1) 786 * Guest writes 1 to the WCE configuration field (writeback mode) 787 * Guest sets DRIVER_OK bit in status field 788 * 789 * s->blk would erroneously be placed in writethrough mode. 790 */ 791 if (!virtio_vdev_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) { 792 aio_context_acquire(blk_get_aio_context(s->blk)); 793 blk_set_enable_write_cache(s->blk, 794 virtio_vdev_has_feature(vdev, 795 VIRTIO_BLK_F_WCE)); 796 aio_context_release(blk_get_aio_context(s->blk)); 797 } 798 } 799 800 static void virtio_blk_save(QEMUFile *f, void *opaque) 801 { 802 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 803 VirtIOBlock *s = VIRTIO_BLK(vdev); 804 805 if (s->dataplane) { 806 virtio_blk_data_plane_stop(s->dataplane); 807 } 808 809 virtio_save(vdev, f); 810 } 811 812 static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f) 813 { 814 VirtIOBlock *s = VIRTIO_BLK(vdev); 815 VirtIOBlockReq *req = s->rq; 816 817 while (req) { 818 qemu_put_sbyte(f, 1); 819 qemu_put_buffer(f, (unsigned char *)&req->elem, 820 sizeof(VirtQueueElement)); 821 req = req->next; 822 } 823 qemu_put_sbyte(f, 0); 824 } 825 826 static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) 827 { 828 VirtIOBlock *s = opaque; 829 VirtIODevice *vdev = VIRTIO_DEVICE(s); 830 831 if (version_id != 2) 832 return -EINVAL; 833 834 return virtio_load(vdev, f, version_id); 835 } 836 837 static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f, 838 int version_id) 839 { 840 VirtIOBlock *s = VIRTIO_BLK(vdev); 841 842 while (qemu_get_sbyte(f)) { 843 VirtIOBlockReq *req = virtio_blk_alloc_request(s); 844 qemu_get_buffer(f, (unsigned char *)&req->elem, 845 sizeof(VirtQueueElement)); 846 req->next = s->rq; 847 s->rq = req; 848 849 virtqueue_map(&req->elem); 850 } 851 852 return 0; 853 } 854 855 static void virtio_blk_resize(void *opaque) 856 { 857 VirtIODevice *vdev = VIRTIO_DEVICE(opaque); 858 859 virtio_notify_config(vdev); 860 } 861 862 static const BlockDevOps virtio_block_ops = { 863 .resize_cb = virtio_blk_resize, 864 }; 865 866 /* Disable dataplane thread during live migration since it does not 867 * update the dirty memory bitmap yet. 868 */ 869 static void virtio_blk_migration_state_changed(Notifier *notifier, void *data) 870 { 871 VirtIOBlock *s = container_of(notifier, VirtIOBlock, 872 migration_state_notifier); 873 MigrationState *mig = data; 874 Error *err = NULL; 875 876 if (migration_in_setup(mig)) { 877 if (!s->dataplane) { 878 return; 879 } 880 virtio_blk_data_plane_destroy(s->dataplane); 881 s->dataplane = NULL; 882 } else if (migration_has_finished(mig) || 883 migration_has_failed(mig)) { 884 if (s->dataplane) { 885 return; 886 } 887 blk_drain_all(); /* complete in-flight non-dataplane requests */ 888 virtio_blk_data_plane_create(VIRTIO_DEVICE(s), &s->conf, 889 &s->dataplane, &err); 890 if (err != NULL) { 891 error_report_err(err); 892 } 893 } 894 } 895 896 static void virtio_blk_device_realize(DeviceState *dev, Error **errp) 897 { 898 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 899 VirtIOBlock *s = VIRTIO_BLK(dev); 900 VirtIOBlkConf *conf = &s->conf; 901 Error *err = NULL; 902 static int virtio_blk_id; 903 904 if (!conf->conf.blk) { 905 error_setg(errp, "drive property not set"); 906 return; 907 } 908 if (!blk_is_inserted(conf->conf.blk)) { 909 error_setg(errp, "Device needs media, but drive is empty"); 910 return; 911 } 912 913 blkconf_serial(&conf->conf, &conf->serial); 914 s->original_wce = blk_enable_write_cache(conf->conf.blk); 915 blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, &err); 916 if (err) { 917 error_propagate(errp, err); 918 return; 919 } 920 blkconf_blocksizes(&conf->conf); 921 922 virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK, 923 sizeof(struct virtio_blk_config)); 924 925 s->blk = conf->conf.blk; 926 s->rq = NULL; 927 s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1; 928 929 s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output); 930 s->complete_request = virtio_blk_complete_request; 931 virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err); 932 if (err != NULL) { 933 error_propagate(errp, err); 934 virtio_cleanup(vdev); 935 return; 936 } 937 s->migration_state_notifier.notify = virtio_blk_migration_state_changed; 938 add_migration_state_change_notifier(&s->migration_state_notifier); 939 940 s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); 941 register_savevm(dev, "virtio-blk", virtio_blk_id++, 2, 942 virtio_blk_save, virtio_blk_load, s); 943 blk_set_dev_ops(s->blk, &virtio_block_ops, s); 944 blk_set_guest_block_size(s->blk, s->conf.conf.logical_block_size); 945 946 blk_iostatus_enable(s->blk); 947 } 948 949 static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp) 950 { 951 VirtIODevice *vdev = VIRTIO_DEVICE(dev); 952 VirtIOBlock *s = VIRTIO_BLK(dev); 953 954 remove_migration_state_change_notifier(&s->migration_state_notifier); 955 virtio_blk_data_plane_destroy(s->dataplane); 956 s->dataplane = NULL; 957 qemu_del_vm_change_state_handler(s->change); 958 unregister_savevm(dev, "virtio-blk", s); 959 blockdev_mark_auto_del(s->blk); 960 virtio_cleanup(vdev); 961 } 962 963 static void virtio_blk_instance_init(Object *obj) 964 { 965 VirtIOBlock *s = VIRTIO_BLK(obj); 966 967 object_property_add_link(obj, "iothread", TYPE_IOTHREAD, 968 (Object **)&s->conf.iothread, 969 qdev_prop_allow_set_link_before_realize, 970 OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL); 971 device_add_bootindex_property(obj, &s->conf.conf.bootindex, 972 "bootindex", "/disk@0,0", 973 DEVICE(obj), NULL); 974 } 975 976 static Property virtio_blk_properties[] = { 977 DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf), 978 DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, conf.conf), 979 DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial), 980 DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true), 981 #ifdef __linux__ 982 DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, false), 983 #endif 984 DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0, 985 true), 986 DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false), 987 DEFINE_PROP_END_OF_LIST(), 988 }; 989 990 static void virtio_blk_class_init(ObjectClass *klass, void *data) 991 { 992 DeviceClass *dc = DEVICE_CLASS(klass); 993 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass); 994 995 dc->props = virtio_blk_properties; 996 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories); 997 vdc->realize = virtio_blk_device_realize; 998 vdc->unrealize = virtio_blk_device_unrealize; 999 vdc->get_config = virtio_blk_update_config; 1000 vdc->set_config = virtio_blk_set_config; 1001 vdc->get_features = virtio_blk_get_features; 1002 vdc->set_status = virtio_blk_set_status; 1003 vdc->reset = virtio_blk_reset; 1004 vdc->save = virtio_blk_save_device; 1005 vdc->load = virtio_blk_load_device; 1006 } 1007 1008 static const TypeInfo virtio_device_info = { 1009 .name = TYPE_VIRTIO_BLK, 1010 .parent = TYPE_VIRTIO_DEVICE, 1011 .instance_size = sizeof(VirtIOBlock), 1012 .instance_init = virtio_blk_instance_init, 1013 .class_init = virtio_blk_class_init, 1014 }; 1015 1016 static void virtio_register_types(void) 1017 { 1018 type_register_static(&virtio_device_info); 1019 } 1020 1021 type_init(virtio_register_types) 1022