4 * Copyright IBM, Corp. 2007
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-error.h"
18 #include "virtio-blk.h"
23 typedef struct VirtIOBlock
31 unsigned short sector_mask;
32 char sn[BLOCK_SERIAL_STRLEN];
36 static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
38 return (VirtIOBlock *)vdev;
41 typedef struct VirtIOBlockReq
44 VirtQueueElement elem;
45 struct virtio_blk_inhdr *in;
46 struct virtio_blk_outhdr *out;
47 struct virtio_scsi_inhdr *scsi;
49 struct VirtIOBlockReq *next;
52 static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
54 VirtIOBlock *s = req->dev;
56 trace_virtio_blk_req_complete(req, status);
58 stb_p(&req->in->status, status);
59 virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
60 virtio_notify(&s->vdev, s->vq);
65 static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
68 BlockErrorAction action = bdrv_get_on_error(req->dev->bs, is_read);
69 VirtIOBlock *s = req->dev;
71 if (action == BLOCK_ERR_IGNORE) {
72 bdrv_mon_event(s->bs, BDRV_ACTION_IGNORE, is_read);
76 if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
77 || action == BLOCK_ERR_STOP_ANY) {
80 bdrv_mon_event(s->bs, BDRV_ACTION_STOP, is_read);
83 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
84 bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, is_read);
90 static void virtio_blk_rw_complete(void *opaque, int ret)
92 VirtIOBlockReq *req = opaque;
94 trace_virtio_blk_rw_complete(req, ret);
97 int is_read = !(ldl_p(&req->out->type) & VIRTIO_BLK_T_OUT);
98 if (virtio_blk_handle_rw_error(req, -ret, is_read))
102 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
105 static void virtio_blk_flush_complete(void *opaque, int ret)
107 VirtIOBlockReq *req = opaque;
110 if (virtio_blk_handle_rw_error(req, -ret, 0)) {
115 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
118 static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
120 VirtIOBlockReq *req = qemu_malloc(sizeof(*req));
127 static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
129 VirtIOBlockReq *req = virtio_blk_alloc_request(s);
132 if (!virtqueue_pop(s->vq, &req->elem)) {
142 static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
144 struct sg_io_hdr hdr;
150 * We require at least one output segment each for the virtio_blk_outhdr
151 * and the SCSI command block.
153 * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
154 * and the sense buffer pointer in the input segments.
156 if (req->elem.out_num < 2 || req->elem.in_num < 3) {
157 virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
162 * No support for bidirection commands yet.
164 if (req->elem.out_num > 2 && req->elem.in_num > 3) {
165 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
170 * The scsi inhdr is placed in the second-to-last input segment, just
171 * before the regular inhdr.
173 req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
175 memset(&hdr, 0, sizeof(struct sg_io_hdr));
176 hdr.interface_id = 'S';
177 hdr.cmd_len = req->elem.out_sg[1].iov_len;
178 hdr.cmdp = req->elem.out_sg[1].iov_base;
181 if (req->elem.out_num > 2) {
183 * If there are more than the minimally required 2 output segments
184 * there is write payload starting from the third iovec.
186 hdr.dxfer_direction = SG_DXFER_TO_DEV;
187 hdr.iovec_count = req->elem.out_num - 2;
189 for (i = 0; i < hdr.iovec_count; i++)
190 hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
192 hdr.dxferp = req->elem.out_sg + 2;
194 } else if (req->elem.in_num > 3) {
196 * If we have more than 3 input segments the guest wants to actually
199 hdr.dxfer_direction = SG_DXFER_FROM_DEV;
200 hdr.iovec_count = req->elem.in_num - 3;
201 for (i = 0; i < hdr.iovec_count; i++)
202 hdr.dxfer_len += req->elem.in_sg[i].iov_len;
204 hdr.dxferp = req->elem.in_sg;
207 * Some SCSI commands don't actually transfer any data.
209 hdr.dxfer_direction = SG_DXFER_NONE;
212 hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
213 hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
215 ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr);
217 status = VIRTIO_BLK_S_UNSUPP;
219 hdr.resid = hdr.dxfer_len;
220 } else if (hdr.status) {
221 status = VIRTIO_BLK_S_IOERR;
223 status = VIRTIO_BLK_S_OK;
226 stl_p(&req->scsi->errors, hdr.status);
227 stl_p(&req->scsi->residual, hdr.resid);
228 stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
229 stl_p(&req->scsi->data_len, hdr.dxfer_len);
231 virtio_blk_req_complete(req, status);
234 static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
236 virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
238 #endif /* __linux__ */
240 typedef struct MultiReqBuffer {
241 BlockRequest blkreq[32];
242 unsigned int num_writes;
245 static void virtio_submit_multiwrite(BlockDriverState *bs, MultiReqBuffer *mrb)
249 if (!mrb->num_writes) {
253 ret = bdrv_aio_multiwrite(bs, mrb->blkreq, mrb->num_writes);
255 for (i = 0; i < mrb->num_writes; i++) {
256 if (mrb->blkreq[i].error) {
257 virtio_blk_rw_complete(mrb->blkreq[i].opaque, -EIO);
265 static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
267 BlockDriverAIOCB *acb;
270 * Make sure all outstanding writes are posted to the backing device.
272 virtio_submit_multiwrite(req->dev->bs, mrb);
274 acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
276 virtio_blk_flush_complete(req, -EIO);
280 static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
282 BlockRequest *blkreq;
285 sector = ldq_p(&req->out->sector);
287 trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
289 if (sector & req->dev->sector_mask) {
290 virtio_blk_rw_complete(req, -EIO);
293 if (req->qiov.size % req->dev->conf->logical_block_size) {
294 virtio_blk_rw_complete(req, -EIO);
298 if (mrb->num_writes == 32) {
299 virtio_submit_multiwrite(req->dev->bs, mrb);
302 blkreq = &mrb->blkreq[mrb->num_writes];
303 blkreq->sector = sector;
304 blkreq->nb_sectors = req->qiov.size / BDRV_SECTOR_SIZE;
305 blkreq->qiov = &req->qiov;
306 blkreq->cb = virtio_blk_rw_complete;
307 blkreq->opaque = req;
313 static void virtio_blk_handle_read(VirtIOBlockReq *req)
315 BlockDriverAIOCB *acb;
318 sector = ldq_p(&req->out->sector);
320 if (sector & req->dev->sector_mask) {
321 virtio_blk_rw_complete(req, -EIO);
324 if (req->qiov.size % req->dev->conf->logical_block_size) {
325 virtio_blk_rw_complete(req, -EIO);
329 acb = bdrv_aio_readv(req->dev->bs, sector, &req->qiov,
330 req->qiov.size / BDRV_SECTOR_SIZE,
331 virtio_blk_rw_complete, req);
333 virtio_blk_rw_complete(req, -EIO);
337 static void virtio_blk_handle_request(VirtIOBlockReq *req,
342 if (req->elem.out_num < 1 || req->elem.in_num < 1) {
343 error_report("virtio-blk missing headers");
347 if (req->elem.out_sg[0].iov_len < sizeof(*req->out) ||
348 req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) {
349 error_report("virtio-blk header not in correct element");
353 req->out = (void *)req->elem.out_sg[0].iov_base;
354 req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
356 type = ldl_p(&req->out->type);
358 if (type & VIRTIO_BLK_T_FLUSH) {
359 virtio_blk_handle_flush(req, mrb);
360 } else if (type & VIRTIO_BLK_T_SCSI_CMD) {
361 virtio_blk_handle_scsi(req);
362 } else if (type & VIRTIO_BLK_T_GET_ID) {
363 VirtIOBlock *s = req->dev;
365 memcpy(req->elem.in_sg[0].iov_base, s->sn,
366 MIN(req->elem.in_sg[0].iov_len, sizeof(s->sn)));
367 virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
368 } else if (type & VIRTIO_BLK_T_OUT) {
369 qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
370 req->elem.out_num - 1);
371 virtio_blk_handle_write(req, mrb);
373 qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
374 req->elem.in_num - 1);
375 virtio_blk_handle_read(req);
379 static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
381 VirtIOBlock *s = to_virtio_blk(vdev);
383 MultiReqBuffer mrb = {
387 while ((req = virtio_blk_get_request(s))) {
388 virtio_blk_handle_request(req, &mrb);
391 virtio_submit_multiwrite(s->bs, &mrb);
394 * FIXME: Want to check for completions before returning to guest mode,
395 * so cached reads and writes are reported as quickly as possible. But
396 * that should be done in the generic block layer.
400 static void virtio_blk_dma_restart_bh(void *opaque)
402 VirtIOBlock *s = opaque;
403 VirtIOBlockReq *req = s->rq;
404 MultiReqBuffer mrb = {
408 qemu_bh_delete(s->bh);
414 virtio_blk_handle_request(req, &mrb);
418 virtio_submit_multiwrite(s->bs, &mrb);
421 static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
423 VirtIOBlock *s = opaque;
429 s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s);
430 qemu_bh_schedule(s->bh);
434 static void virtio_blk_reset(VirtIODevice *vdev)
437 * This should cancel pending requests, but can't do nicely until there
438 * are per-device request lists.
443 /* coalesce internal state, copy to pci i/o region 0
445 static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config)
447 VirtIOBlock *s = to_virtio_blk(vdev);
448 struct virtio_blk_config blkcfg;
450 int cylinders, heads, secs;
452 bdrv_get_geometry(s->bs, &capacity);
453 bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs);
454 memset(&blkcfg, 0, sizeof(blkcfg));
455 stq_raw(&blkcfg.capacity, capacity);
456 stl_raw(&blkcfg.seg_max, 128 - 2);
457 stw_raw(&blkcfg.cylinders, cylinders);
458 blkcfg.heads = heads;
459 blkcfg.sectors = secs & ~s->sector_mask;
460 blkcfg.blk_size = s->conf->logical_block_size;
462 blkcfg.physical_block_exp = get_physical_block_exp(s->conf);
463 blkcfg.alignment_offset = 0;
464 blkcfg.min_io_size = s->conf->min_io_size / blkcfg.blk_size;
465 blkcfg.opt_io_size = s->conf->opt_io_size / blkcfg.blk_size;
466 memcpy(config, &blkcfg, sizeof(struct virtio_blk_config));
469 static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
471 VirtIOBlock *s = to_virtio_blk(vdev);
473 features |= (1 << VIRTIO_BLK_F_SEG_MAX);
474 features |= (1 << VIRTIO_BLK_F_GEOMETRY);
475 features |= (1 << VIRTIO_BLK_F_TOPOLOGY);
476 features |= (1 << VIRTIO_BLK_F_BLK_SIZE);
478 if (bdrv_enable_write_cache(s->bs))
479 features |= (1 << VIRTIO_BLK_F_WCACHE);
481 if (bdrv_is_read_only(s->bs))
482 features |= 1 << VIRTIO_BLK_F_RO;
487 static void virtio_blk_save(QEMUFile *f, void *opaque)
489 VirtIOBlock *s = opaque;
490 VirtIOBlockReq *req = s->rq;
492 virtio_save(&s->vdev, f);
495 qemu_put_sbyte(f, 1);
496 qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
499 qemu_put_sbyte(f, 0);
502 static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
504 VirtIOBlock *s = opaque;
509 virtio_load(&s->vdev, f);
510 while (qemu_get_sbyte(f)) {
511 VirtIOBlockReq *req = virtio_blk_alloc_request(s);
512 qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
516 virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr,
517 req->elem.in_num, 1);
518 virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr,
519 req->elem.out_num, 0);
525 static void virtio_blk_change_cb(void *opaque, int reason)
527 VirtIOBlock *s = opaque;
529 if (reason & CHANGE_SIZE) {
530 virtio_notify_config(&s->vdev);
534 VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf)
537 int cylinders, heads, secs;
538 static int virtio_blk_id;
542 error_report("virtio-blk-pci: drive property not set");
545 if (!bdrv_is_inserted(conf->bs)) {
546 error_report("Device needs media, but drive is empty");
550 s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
551 sizeof(struct virtio_blk_config),
552 sizeof(VirtIOBlock));
554 s->vdev.get_config = virtio_blk_update_config;
555 s->vdev.get_features = virtio_blk_get_features;
556 s->vdev.reset = virtio_blk_reset;
560 s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
561 bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
563 /* NB: per existing s/n string convention the string is terminated
564 * by '\0' only when less than sizeof (s->sn)
566 dinfo = drive_get_by_blockdev(s->bs);
567 strncpy(s->sn, dinfo->serial, sizeof (s->sn));
569 s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
571 qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
573 register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
574 virtio_blk_save, virtio_blk_load, s);
575 bdrv_set_removable(s->bs, 0);
576 bdrv_set_change_cb(s->bs, virtio_blk_change_cb, s);
577 s->bs->buffer_alignment = conf->logical_block_size;
579 add_boot_device_path(conf->bootindex, dev, "/disk@0,0");
584 void virtio_blk_exit(VirtIODevice *vdev)
586 VirtIOBlock *s = to_virtio_blk(vdev);
587 unregister_savevm(s->qdev, "virtio-blk", s);