virtio: add feature checking helpers
[qemu.git] / hw / block / virtio-blk.c
blob1e5b918620be76ec74bd21ce6041bacc43fc13ca
1 /*
2 * Virtio Block Device
4 * Copyright IBM, Corp. 2007
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
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"
31 VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
33 VirtIOBlockReq *req = g_slice_new(VirtIOBlockReq);
34 req->dev = s;
35 req->qiov.size = 0;
36 req->next = NULL;
37 req->mr_next = NULL;
38 return req;
41 void virtio_blk_free_request(VirtIOBlockReq *req)
43 if (req) {
44 g_slice_free(VirtIOBlockReq, req);
48 static void virtio_blk_complete_request(VirtIOBlockReq *req,
49 unsigned char status)
51 VirtIOBlock *s = req->dev;
52 VirtIODevice *vdev = VIRTIO_DEVICE(s);
54 trace_virtio_blk_req_complete(req, status);
56 stb_p(&req->in->status, status);
57 virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
58 virtio_notify(vdev, s->vq);
61 static void virtio_blk_req_complete(VirtIOBlockReq *req, unsigned char status)
63 req->dev->complete_request(req, status);
66 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
67 bool is_read)
69 BlockErrorAction action = blk_get_error_action(req->dev->blk,
70 is_read, error);
71 VirtIOBlock *s = req->dev;
73 if (action == BLOCK_ERROR_ACTION_STOP) {
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_done(blk_get_stats(s->blk), &req->acct);
79 virtio_blk_free_request(req);
82 blk_error_action(s->blk, action, is_read, error);
83 return action != BLOCK_ERROR_ACTION_IGNORE;
86 static void virtio_blk_rw_complete(void *opaque, int ret)
88 VirtIOBlockReq *next = opaque;
90 while (next) {
91 VirtIOBlockReq *req = next;
92 next = req->mr_next;
93 trace_virtio_blk_rw_complete(req, ret);
95 if (req->qiov.nalloc != -1) {
96 /* If nalloc is != 1 req->qiov is a local copy of the original
97 * external iovec. It was allocated in submit_merged_requests
98 * to be able to merge requests. */
99 qemu_iovec_destroy(&req->qiov);
102 if (ret) {
103 int p = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type);
104 bool is_read = !(p & VIRTIO_BLK_T_OUT);
105 if (virtio_blk_handle_rw_error(req, -ret, is_read)) {
106 continue;
110 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
111 block_acct_done(blk_get_stats(req->dev->blk), &req->acct);
112 virtio_blk_free_request(req);
116 static void virtio_blk_flush_complete(void *opaque, int ret)
118 VirtIOBlockReq *req = opaque;
120 if (ret) {
121 if (virtio_blk_handle_rw_error(req, -ret, 0)) {
122 return;
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);
131 #ifdef __linux__
133 typedef struct {
134 VirtIOBlockReq *req;
135 struct sg_io_hdr hdr;
136 } VirtIOBlockIoctlReq;
138 static void virtio_blk_ioctl_complete(void *opaque, int status)
140 VirtIOBlockIoctlReq *ioctl_req = opaque;
141 VirtIOBlockReq *req = ioctl_req->req;
142 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
143 struct virtio_scsi_inhdr *scsi;
144 struct sg_io_hdr *hdr;
146 scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
148 if (status) {
149 status = VIRTIO_BLK_S_UNSUPP;
150 virtio_stl_p(vdev, &scsi->errors, 255);
151 goto out;
154 hdr = &ioctl_req->hdr;
156 * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
157 * clear the masked_status field [hence status gets cleared too, see
158 * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
159 * status has occurred. However they do set DRIVER_SENSE in driver_status
160 * field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
162 if (hdr->status == 0 && hdr->sb_len_wr > 0) {
163 hdr->status = CHECK_CONDITION;
166 virtio_stl_p(vdev, &scsi->errors,
167 hdr->status | (hdr->msg_status << 8) |
168 (hdr->host_status << 16) | (hdr->driver_status << 24));
169 virtio_stl_p(vdev, &scsi->residual, hdr->resid);
170 virtio_stl_p(vdev, &scsi->sense_len, hdr->sb_len_wr);
171 virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len);
173 out:
174 virtio_blk_req_complete(req, status);
175 virtio_blk_free_request(req);
176 g_free(ioctl_req);
179 #endif
181 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
183 VirtIOBlockReq *req = virtio_blk_alloc_request(s);
185 if (!virtqueue_pop(s->vq, &req->elem)) {
186 virtio_blk_free_request(req);
187 return NULL;
190 return req;
193 static int virtio_blk_handle_scsi_req(VirtIOBlockReq *req)
195 int status = VIRTIO_BLK_S_OK;
196 struct virtio_scsi_inhdr *scsi = NULL;
197 VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
198 VirtQueueElement *elem = &req->elem;
199 VirtIOBlock *blk = req->dev;
201 #ifdef __linux__
202 int i;
203 VirtIOBlockIoctlReq *ioctl_req;
204 #endif
207 * We require at least one output segment each for the virtio_blk_outhdr
208 * and the SCSI command block.
210 * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
211 * and the sense buffer pointer in the input segments.
213 if (elem->out_num < 2 || elem->in_num < 3) {
214 status = VIRTIO_BLK_S_IOERR;
215 goto fail;
219 * The scsi inhdr is placed in the second-to-last input segment, just
220 * before the regular inhdr.
222 scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base;
224 if (!blk->conf.scsi) {
225 status = VIRTIO_BLK_S_UNSUPP;
226 goto fail;
230 * No support for bidirection commands yet.
232 if (elem->out_num > 2 && elem->in_num > 3) {
233 status = VIRTIO_BLK_S_UNSUPP;
234 goto fail;
237 #ifdef __linux__
238 ioctl_req = g_new0(VirtIOBlockIoctlReq, 1);
239 ioctl_req->req = req;
240 ioctl_req->hdr.interface_id = 'S';
241 ioctl_req->hdr.cmd_len = elem->out_sg[1].iov_len;
242 ioctl_req->hdr.cmdp = elem->out_sg[1].iov_base;
243 ioctl_req->hdr.dxfer_len = 0;
245 if (elem->out_num > 2) {
247 * If there are more than the minimally required 2 output segments
248 * there is write payload starting from the third iovec.
250 ioctl_req->hdr.dxfer_direction = SG_DXFER_TO_DEV;
251 ioctl_req->hdr.iovec_count = elem->out_num - 2;
253 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {
254 ioctl_req->hdr.dxfer_len += elem->out_sg[i + 2].iov_len;
257 ioctl_req->hdr.dxferp = elem->out_sg + 2;
259 } else if (elem->in_num > 3) {
261 * If we have more than 3 input segments the guest wants to actually
262 * read data.
264 ioctl_req->hdr.dxfer_direction = SG_DXFER_FROM_DEV;
265 ioctl_req->hdr.iovec_count = elem->in_num - 3;
266 for (i = 0; i < ioctl_req->hdr.iovec_count; i++) {
267 ioctl_req->hdr.dxfer_len += elem->in_sg[i].iov_len;
270 ioctl_req->hdr.dxferp = elem->in_sg;
271 } else {
273 * Some SCSI commands don't actually transfer any data.
275 ioctl_req->hdr.dxfer_direction = SG_DXFER_NONE;
278 ioctl_req->hdr.sbp = elem->in_sg[elem->in_num - 3].iov_base;
279 ioctl_req->hdr.mx_sb_len = elem->in_sg[elem->in_num - 3].iov_len;
281 blk_aio_ioctl(blk->blk, SG_IO, &ioctl_req->hdr,
282 virtio_blk_ioctl_complete, ioctl_req);
283 return -EINPROGRESS;
284 #else
285 abort();
286 #endif
288 fail:
289 /* Just put anything nonzero so that the ioctl fails in the guest. */
290 if (scsi) {
291 virtio_stl_p(vdev, &scsi->errors, 255);
293 return status;
296 static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
298 int status;
300 status = virtio_blk_handle_scsi_req(req);
301 if (status != -EINPROGRESS) {
302 virtio_blk_req_complete(req, status);
303 virtio_blk_free_request(req);
307 static inline void submit_requests(BlockBackend *blk, MultiReqBuffer *mrb,
308 int start, int num_reqs, int niov)
310 QEMUIOVector *qiov = &mrb->reqs[start]->qiov;
311 int64_t sector_num = mrb->reqs[start]->sector_num;
312 int nb_sectors = mrb->reqs[start]->qiov.size / BDRV_SECTOR_SIZE;
313 bool is_write = mrb->is_write;
315 if (num_reqs > 1) {
316 int i;
317 struct iovec *tmp_iov = qiov->iov;
318 int tmp_niov = qiov->niov;
320 /* mrb->reqs[start]->qiov was initialized from external so we can't
321 * modifiy it here. We need to initialize it locally and then add the
322 * external iovecs. */
323 qemu_iovec_init(qiov, niov);
325 for (i = 0; i < tmp_niov; i++) {
326 qemu_iovec_add(qiov, tmp_iov[i].iov_base, tmp_iov[i].iov_len);
329 for (i = start + 1; i < start + num_reqs; i++) {
330 qemu_iovec_concat(qiov, &mrb->reqs[i]->qiov, 0,
331 mrb->reqs[i]->qiov.size);
332 mrb->reqs[i - 1]->mr_next = mrb->reqs[i];
333 nb_sectors += mrb->reqs[i]->qiov.size / BDRV_SECTOR_SIZE;
335 assert(nb_sectors == qiov->size / BDRV_SECTOR_SIZE);
337 trace_virtio_blk_submit_multireq(mrb, start, num_reqs, sector_num,
338 nb_sectors, is_write);
339 block_acct_merge_done(blk_get_stats(blk),
340 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ,
341 num_reqs - 1);
344 if (is_write) {
345 blk_aio_writev(blk, sector_num, qiov, nb_sectors,
346 virtio_blk_rw_complete, mrb->reqs[start]);
347 } else {
348 blk_aio_readv(blk, sector_num, qiov, nb_sectors,
349 virtio_blk_rw_complete, mrb->reqs[start]);
353 static int multireq_compare(const void *a, const void *b)
355 const VirtIOBlockReq *req1 = *(VirtIOBlockReq **)a,
356 *req2 = *(VirtIOBlockReq **)b;
359 * Note that we can't simply subtract sector_num1 from sector_num2
360 * here as that could overflow the return value.
362 if (req1->sector_num > req2->sector_num) {
363 return 1;
364 } else if (req1->sector_num < req2->sector_num) {
365 return -1;
366 } else {
367 return 0;
371 void virtio_blk_submit_multireq(BlockBackend *blk, MultiReqBuffer *mrb)
373 int i = 0, start = 0, num_reqs = 0, niov = 0, nb_sectors = 0;
374 int max_xfer_len = 0;
375 int64_t sector_num = 0;
377 if (mrb->num_reqs == 1) {
378 submit_requests(blk, mrb, 0, 1, -1);
379 mrb->num_reqs = 0;
380 return;
383 max_xfer_len = blk_get_max_transfer_length(mrb->reqs[0]->dev->blk);
384 max_xfer_len = MIN_NON_ZERO(max_xfer_len, BDRV_REQUEST_MAX_SECTORS);
386 qsort(mrb->reqs, mrb->num_reqs, sizeof(*mrb->reqs),
387 &multireq_compare);
389 for (i = 0; i < mrb->num_reqs; i++) {
390 VirtIOBlockReq *req = mrb->reqs[i];
391 if (num_reqs > 0) {
392 bool merge = true;
394 /* merge would exceed maximum number of IOVs */
395 if (niov + req->qiov.niov > IOV_MAX) {
396 merge = false;
399 /* merge would exceed maximum transfer length of backend device */
400 if (req->qiov.size / BDRV_SECTOR_SIZE + nb_sectors > max_xfer_len) {
401 merge = false;
404 /* requests are not sequential */
405 if (sector_num + nb_sectors != req->sector_num) {
406 merge = false;
409 if (!merge) {
410 submit_requests(blk, mrb, start, num_reqs, niov);
411 num_reqs = 0;
415 if (num_reqs == 0) {
416 sector_num = req->sector_num;
417 nb_sectors = niov = 0;
418 start = i;
421 nb_sectors += req->qiov.size / BDRV_SECTOR_SIZE;
422 niov += req->qiov.niov;
423 num_reqs++;
426 submit_requests(blk, mrb, start, num_reqs, niov);
427 mrb->num_reqs = 0;
430 static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
432 block_acct_start(blk_get_stats(req->dev->blk), &req->acct, 0,
433 BLOCK_ACCT_FLUSH);
436 * Make sure all outstanding writes are posted to the backing device.
438 if (mrb->is_write && mrb->num_reqs > 0) {
439 virtio_blk_submit_multireq(req->dev->blk, mrb);
441 blk_aio_flush(req->dev->blk, virtio_blk_flush_complete, req);
444 static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
445 uint64_t sector, size_t size)
447 uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
448 uint64_t total_sectors;
450 if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
451 return false;
453 if (sector & dev->sector_mask) {
454 return false;
456 if (size % dev->conf.conf.logical_block_size) {
457 return false;
459 blk_get_geometry(dev->blk, &total_sectors);
460 if (sector > total_sectors || nb_sectors > total_sectors - sector) {
461 return false;
463 return true;
466 void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
468 uint32_t type;
469 struct iovec *in_iov = req->elem.in_sg;
470 struct iovec *iov = req->elem.out_sg;
471 unsigned in_num = req->elem.in_num;
472 unsigned out_num = req->elem.out_num;
474 if (req->elem.out_num < 1 || req->elem.in_num < 1) {
475 error_report("virtio-blk missing headers");
476 exit(1);
479 if (unlikely(iov_to_buf(iov, out_num, 0, &req->out,
480 sizeof(req->out)) != sizeof(req->out))) {
481 error_report("virtio-blk request outhdr too short");
482 exit(1);
485 iov_discard_front(&iov, &out_num, sizeof(req->out));
487 if (in_num < 1 ||
488 in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
489 error_report("virtio-blk request inhdr too short");
490 exit(1);
493 req->in = (void *)in_iov[in_num - 1].iov_base
494 + in_iov[in_num - 1].iov_len
495 - sizeof(struct virtio_blk_inhdr);
496 iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
498 type = virtio_ldl_p(VIRTIO_DEVICE(req->dev), &req->out.type);
500 /* VIRTIO_BLK_T_OUT defines the command direction. VIRTIO_BLK_T_BARRIER
501 * is an optional flag. Altough a guest should not send this flag if
502 * not negotiated we ignored it in the past. So keep ignoring it. */
503 switch (type & ~(VIRTIO_BLK_T_OUT | VIRTIO_BLK_T_BARRIER)) {
504 case VIRTIO_BLK_T_IN:
506 bool is_write = type & VIRTIO_BLK_T_OUT;
507 req->sector_num = virtio_ldq_p(VIRTIO_DEVICE(req->dev),
508 &req->out.sector);
510 if (is_write) {
511 qemu_iovec_init_external(&req->qiov, iov, out_num);
512 trace_virtio_blk_handle_write(req, req->sector_num,
513 req->qiov.size / BDRV_SECTOR_SIZE);
514 } else {
515 qemu_iovec_init_external(&req->qiov, in_iov, in_num);
516 trace_virtio_blk_handle_read(req, req->sector_num,
517 req->qiov.size / BDRV_SECTOR_SIZE);
520 if (!virtio_blk_sect_range_ok(req->dev, req->sector_num,
521 req->qiov.size)) {
522 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
523 virtio_blk_free_request(req);
524 return;
527 block_acct_start(blk_get_stats(req->dev->blk),
528 &req->acct, req->qiov.size,
529 is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
531 /* merge would exceed maximum number of requests or IO direction
532 * changes */
533 if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS ||
534 is_write != mrb->is_write ||
535 !req->dev->conf.request_merging)) {
536 virtio_blk_submit_multireq(req->dev->blk, mrb);
539 assert(mrb->num_reqs < VIRTIO_BLK_MAX_MERGE_REQS);
540 mrb->reqs[mrb->num_reqs++] = req;
541 mrb->is_write = is_write;
542 break;
544 case VIRTIO_BLK_T_FLUSH:
545 virtio_blk_handle_flush(req, mrb);
546 break;
547 case VIRTIO_BLK_T_SCSI_CMD:
548 virtio_blk_handle_scsi(req);
549 break;
550 case VIRTIO_BLK_T_GET_ID:
552 VirtIOBlock *s = req->dev;
555 * NB: per existing s/n string convention the string is
556 * terminated by '\0' only when shorter than buffer.
558 const char *serial = s->conf.serial ? s->conf.serial : "";
559 size_t size = MIN(strlen(serial) + 1,
560 MIN(iov_size(in_iov, in_num),
561 VIRTIO_BLK_ID_BYTES));
562 iov_from_buf(in_iov, in_num, 0, serial, size);
563 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
564 virtio_blk_free_request(req);
565 break;
567 default:
568 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
569 virtio_blk_free_request(req);
573 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
575 VirtIOBlock *s = VIRTIO_BLK(vdev);
576 VirtIOBlockReq *req;
577 MultiReqBuffer mrb = {};
579 /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
580 * dataplane here instead of waiting for .set_status().
582 if (s->dataplane) {
583 virtio_blk_data_plane_start(s->dataplane);
584 return;
587 while ((req = virtio_blk_get_request(s))) {
588 virtio_blk_handle_request(req, &mrb);
591 if (mrb.num_reqs) {
592 virtio_blk_submit_multireq(s->blk, &mrb);
596 * FIXME: Want to check for completions before returning to guest mode,
597 * so cached reads and writes are reported as quickly as possible. But
598 * that should be done in the generic block layer.
602 static void virtio_blk_dma_restart_bh(void *opaque)
604 VirtIOBlock *s = opaque;
605 VirtIOBlockReq *req = s->rq;
606 MultiReqBuffer mrb = {};
608 qemu_bh_delete(s->bh);
609 s->bh = NULL;
611 s->rq = NULL;
613 while (req) {
614 VirtIOBlockReq *next = req->next;
615 virtio_blk_handle_request(req, &mrb);
616 req = next;
619 if (mrb.num_reqs) {
620 virtio_blk_submit_multireq(s->blk, &mrb);
624 static void virtio_blk_dma_restart_cb(void *opaque, int running,
625 RunState state)
627 VirtIOBlock *s = opaque;
629 if (!running) {
630 return;
633 if (!s->bh) {
634 s->bh = aio_bh_new(blk_get_aio_context(s->conf.conf.blk),
635 virtio_blk_dma_restart_bh, s);
636 qemu_bh_schedule(s->bh);
640 static void virtio_blk_reset(VirtIODevice *vdev)
642 VirtIOBlock *s = VIRTIO_BLK(vdev);
644 if (s->dataplane) {
645 virtio_blk_data_plane_stop(s->dataplane);
649 * This should cancel pending requests, but can't do nicely until there
650 * are per-device request lists.
652 blk_drain_all();
653 blk_set_enable_write_cache(s->blk, s->original_wce);
656 /* coalesce internal state, copy to pci i/o region 0
658 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
660 VirtIOBlock *s = VIRTIO_BLK(vdev);
661 BlockConf *conf = &s->conf.conf;
662 struct virtio_blk_config blkcfg;
663 uint64_t capacity;
664 int blk_size = conf->logical_block_size;
666 blk_get_geometry(s->blk, &capacity);
667 memset(&blkcfg, 0, sizeof(blkcfg));
668 virtio_stq_p(vdev, &blkcfg.capacity, capacity);
669 virtio_stl_p(vdev, &blkcfg.seg_max, 128 - 2);
670 virtio_stw_p(vdev, &blkcfg.geometry.cylinders, conf->cyls);
671 virtio_stl_p(vdev, &blkcfg.blk_size, blk_size);
672 virtio_stw_p(vdev, &blkcfg.min_io_size, conf->min_io_size / blk_size);
673 virtio_stw_p(vdev, &blkcfg.opt_io_size, conf->opt_io_size / blk_size);
674 blkcfg.geometry.heads = conf->heads;
676 * We must ensure that the block device capacity is a multiple of
677 * the logical block size. If that is not the case, let's use
678 * sector_mask to adopt the geometry to have a correct picture.
679 * For those devices where the capacity is ok for the given geometry
680 * we don't touch the sector value of the geometry, since some devices
681 * (like s390 dasd) need a specific value. Here the capacity is already
682 * cyls*heads*secs*blk_size and the sector value is not block size
683 * divided by 512 - instead it is the amount of blk_size blocks
684 * per track (cylinder).
686 if (blk_getlength(s->blk) / conf->heads / conf->secs % blk_size) {
687 blkcfg.geometry.sectors = conf->secs & ~s->sector_mask;
688 } else {
689 blkcfg.geometry.sectors = conf->secs;
691 blkcfg.size_max = 0;
692 blkcfg.physical_block_exp = get_physical_block_exp(conf);
693 blkcfg.alignment_offset = 0;
694 blkcfg.wce = blk_enable_write_cache(s->blk);
695 memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
698 static void virtio_blk_set_config(VirtIODevice *vdev, const uint8_t *config)
700 VirtIOBlock *s = VIRTIO_BLK(vdev);
701 struct virtio_blk_config blkcfg;
703 memcpy(&blkcfg, config, sizeof(blkcfg));
705 aio_context_acquire(blk_get_aio_context(s->blk));
706 blk_set_enable_write_cache(s->blk, blkcfg.wce != 0);
707 aio_context_release(blk_get_aio_context(s->blk));
710 static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
712 VirtIOBlock *s = VIRTIO_BLK(vdev);
714 virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
715 virtio_add_feature(&features, VIRTIO_BLK_F_GEOMETRY);
716 virtio_add_feature(&features, VIRTIO_BLK_F_TOPOLOGY);
717 virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
718 virtio_add_feature(&features, VIRTIO_BLK_F_SCSI);
720 if (s->conf.config_wce) {
721 virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
723 if (blk_enable_write_cache(s->blk)) {
724 virtio_add_feature(&features, VIRTIO_BLK_F_WCE);
726 if (blk_is_read_only(s->blk)) {
727 virtio_add_feature(&features, VIRTIO_BLK_F_RO);
730 return features;
733 static void virtio_blk_set_status(VirtIODevice *vdev, uint8_t status)
735 VirtIOBlock *s = VIRTIO_BLK(vdev);
737 if (s->dataplane && !(status & (VIRTIO_CONFIG_S_DRIVER |
738 VIRTIO_CONFIG_S_DRIVER_OK))) {
739 virtio_blk_data_plane_stop(s->dataplane);
742 if (!(status & VIRTIO_CONFIG_S_DRIVER_OK)) {
743 return;
746 /* A guest that supports VIRTIO_BLK_F_CONFIG_WCE must be able to send
747 * cache flushes. Thus, the "auto writethrough" behavior is never
748 * necessary for guests that support the VIRTIO_BLK_F_CONFIG_WCE feature.
749 * Leaving it enabled would break the following sequence:
751 * Guest started with "-drive cache=writethrough"
752 * Guest sets status to 0
753 * Guest sets DRIVER bit in status field
754 * Guest reads host features (WCE=0, CONFIG_WCE=1)
755 * Guest writes guest features (WCE=0, CONFIG_WCE=1)
756 * Guest writes 1 to the WCE configuration field (writeback mode)
757 * Guest sets DRIVER_OK bit in status field
759 * s->blk would erroneously be placed in writethrough mode.
761 if (!virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) {
762 aio_context_acquire(blk_get_aio_context(s->blk));
763 blk_set_enable_write_cache(s->blk,
764 virtio_has_feature(vdev, VIRTIO_BLK_F_WCE));
765 aio_context_release(blk_get_aio_context(s->blk));
769 static void virtio_blk_save(QEMUFile *f, void *opaque)
771 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
773 virtio_save(vdev, f);
776 static void virtio_blk_save_device(VirtIODevice *vdev, QEMUFile *f)
778 VirtIOBlock *s = VIRTIO_BLK(vdev);
779 VirtIOBlockReq *req = s->rq;
781 while (req) {
782 qemu_put_sbyte(f, 1);
783 qemu_put_buffer(f, (unsigned char *)&req->elem,
784 sizeof(VirtQueueElement));
785 req = req->next;
787 qemu_put_sbyte(f, 0);
790 static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
792 VirtIOBlock *s = opaque;
793 VirtIODevice *vdev = VIRTIO_DEVICE(s);
795 if (version_id != 2)
796 return -EINVAL;
798 return virtio_load(vdev, f, version_id);
801 static int virtio_blk_load_device(VirtIODevice *vdev, QEMUFile *f,
802 int version_id)
804 VirtIOBlock *s = VIRTIO_BLK(vdev);
806 while (qemu_get_sbyte(f)) {
807 VirtIOBlockReq *req = virtio_blk_alloc_request(s);
808 qemu_get_buffer(f, (unsigned char *)&req->elem,
809 sizeof(VirtQueueElement));
810 req->next = s->rq;
811 s->rq = req;
813 virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr,
814 req->elem.in_num, 1);
815 virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr,
816 req->elem.out_num, 0);
819 return 0;
822 static void virtio_blk_resize(void *opaque)
824 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
826 virtio_notify_config(vdev);
829 static const BlockDevOps virtio_block_ops = {
830 .resize_cb = virtio_blk_resize,
833 /* Disable dataplane thread during live migration since it does not
834 * update the dirty memory bitmap yet.
836 static void virtio_blk_migration_state_changed(Notifier *notifier, void *data)
838 VirtIOBlock *s = container_of(notifier, VirtIOBlock,
839 migration_state_notifier);
840 MigrationState *mig = data;
841 Error *err = NULL;
843 if (migration_in_setup(mig)) {
844 if (!s->dataplane) {
845 return;
847 virtio_blk_data_plane_destroy(s->dataplane);
848 s->dataplane = NULL;
849 } else if (migration_has_finished(mig) ||
850 migration_has_failed(mig)) {
851 if (s->dataplane) {
852 return;
854 blk_drain_all(); /* complete in-flight non-dataplane requests */
855 virtio_blk_data_plane_create(VIRTIO_DEVICE(s), &s->conf,
856 &s->dataplane, &err);
857 if (err != NULL) {
858 error_report_err(err);
863 static void virtio_blk_device_realize(DeviceState *dev, Error **errp)
865 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
866 VirtIOBlock *s = VIRTIO_BLK(dev);
867 VirtIOBlkConf *conf = &s->conf;
868 Error *err = NULL;
869 static int virtio_blk_id;
871 if (!conf->conf.blk) {
872 error_setg(errp, "drive property not set");
873 return;
875 if (!blk_is_inserted(conf->conf.blk)) {
876 error_setg(errp, "Device needs media, but drive is empty");
877 return;
880 blkconf_serial(&conf->conf, &conf->serial);
881 s->original_wce = blk_enable_write_cache(conf->conf.blk);
882 blkconf_geometry(&conf->conf, NULL, 65535, 255, 255, &err);
883 if (err) {
884 error_propagate(errp, err);
885 return;
888 virtio_init(vdev, "virtio-blk", VIRTIO_ID_BLOCK,
889 sizeof(struct virtio_blk_config));
891 s->blk = conf->conf.blk;
892 s->rq = NULL;
893 s->sector_mask = (s->conf.conf.logical_block_size / BDRV_SECTOR_SIZE) - 1;
895 s->vq = virtio_add_queue(vdev, 128, virtio_blk_handle_output);
896 s->complete_request = virtio_blk_complete_request;
897 virtio_blk_data_plane_create(vdev, conf, &s->dataplane, &err);
898 if (err != NULL) {
899 error_propagate(errp, err);
900 virtio_cleanup(vdev);
901 return;
903 s->migration_state_notifier.notify = virtio_blk_migration_state_changed;
904 add_migration_state_change_notifier(&s->migration_state_notifier);
906 s->change = qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
907 register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
908 virtio_blk_save, virtio_blk_load, s);
909 blk_set_dev_ops(s->blk, &virtio_block_ops, s);
910 blk_set_guest_block_size(s->blk, s->conf.conf.logical_block_size);
912 blk_iostatus_enable(s->blk);
915 static void virtio_blk_device_unrealize(DeviceState *dev, Error **errp)
917 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
918 VirtIOBlock *s = VIRTIO_BLK(dev);
920 remove_migration_state_change_notifier(&s->migration_state_notifier);
921 virtio_blk_data_plane_destroy(s->dataplane);
922 s->dataplane = NULL;
923 qemu_del_vm_change_state_handler(s->change);
924 unregister_savevm(dev, "virtio-blk", s);
925 blockdev_mark_auto_del(s->blk);
926 virtio_cleanup(vdev);
929 static void virtio_blk_instance_init(Object *obj)
931 VirtIOBlock *s = VIRTIO_BLK(obj);
933 object_property_add_link(obj, "iothread", TYPE_IOTHREAD,
934 (Object **)&s->conf.iothread,
935 qdev_prop_allow_set_link_before_realize,
936 OBJ_PROP_LINK_UNREF_ON_RELEASE, NULL);
937 device_add_bootindex_property(obj, &s->conf.conf.bootindex,
938 "bootindex", "/disk@0,0",
939 DEVICE(obj), NULL);
942 static Property virtio_blk_properties[] = {
943 DEFINE_BLOCK_PROPERTIES(VirtIOBlock, conf.conf),
944 DEFINE_BLOCK_CHS_PROPERTIES(VirtIOBlock, conf.conf),
945 DEFINE_PROP_STRING("serial", VirtIOBlock, conf.serial),
946 DEFINE_PROP_BIT("config-wce", VirtIOBlock, conf.config_wce, 0, true),
947 #ifdef __linux__
948 DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true),
949 #endif
950 DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,
951 true),
952 DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false),
953 DEFINE_PROP_END_OF_LIST(),
956 static void virtio_blk_class_init(ObjectClass *klass, void *data)
958 DeviceClass *dc = DEVICE_CLASS(klass);
959 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
961 dc->props = virtio_blk_properties;
962 set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
963 vdc->realize = virtio_blk_device_realize;
964 vdc->unrealize = virtio_blk_device_unrealize;
965 vdc->get_config = virtio_blk_update_config;
966 vdc->set_config = virtio_blk_set_config;
967 vdc->get_features = virtio_blk_get_features;
968 vdc->set_status = virtio_blk_set_status;
969 vdc->reset = virtio_blk_reset;
970 vdc->save = virtio_blk_save_device;
971 vdc->load = virtio_blk_load_device;
974 static const TypeInfo virtio_device_info = {
975 .name = TYPE_VIRTIO_BLK,
976 .parent = TYPE_VIRTIO_DEVICE,
977 .instance_size = sizeof(VirtIOBlock),
978 .instance_init = virtio_blk_instance_init,
979 .class_init = virtio_blk_class_init,
982 static void virtio_register_types(void)
984 type_register_static(&virtio_device_info);
987 type_init(virtio_register_types)