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/*
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* Virtio Block Device
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*
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* Copyright IBM, Corp. 2007
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#include "qemu-common.h" |
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#include "qemu-error.h" |
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#include "trace.h" |
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#include "blockdev.h" |
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#include "virtio-blk.h" |
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#include "scsi-defs.h" |
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#ifdef __linux__
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# include <scsi/sg.h> |
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#endif
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typedef struct VirtIOBlock |
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{ |
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VirtIODevice vdev; |
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BlockDriverState *bs; |
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VirtQueue *vq; |
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void *rq;
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QEMUBH *bh; |
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BlockConf *conf; |
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char *serial;
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unsigned short sector_mask; |
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DeviceState *qdev; |
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} VirtIOBlock; |
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static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
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{ |
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return (VirtIOBlock *)vdev;
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} |
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typedef struct VirtIOBlockReq |
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{ |
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VirtIOBlock *dev; |
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VirtQueueElement elem; |
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struct virtio_blk_inhdr *in;
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struct virtio_blk_outhdr *out;
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struct virtio_scsi_inhdr *scsi;
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QEMUIOVector qiov; |
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struct VirtIOBlockReq *next;
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BlockAcctCookie acct; |
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} VirtIOBlockReq; |
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static void virtio_blk_req_complete(VirtIOBlockReq *req, int status) |
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{ |
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VirtIOBlock *s = req->dev; |
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trace_virtio_blk_req_complete(req, status); |
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stb_p(&req->in->status, status); |
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virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
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virtio_notify(&s->vdev, s->vq); |
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} |
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static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error, |
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int is_read)
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{ |
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BlockErrorAction action = bdrv_get_on_error(req->dev->bs, is_read); |
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VirtIOBlock *s = req->dev; |
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if (action == BLOCK_ERR_IGNORE) {
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bdrv_mon_event(s->bs, BDRV_ACTION_IGNORE, is_read); |
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return 0; |
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} |
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if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
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|| action == BLOCK_ERR_STOP_ANY) { |
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req->next = s->rq; |
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s->rq = req; |
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bdrv_mon_event(s->bs, BDRV_ACTION_STOP, is_read); |
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vm_stop(RUN_STATE_IO_ERROR); |
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bdrv_iostatus_set_err(s->bs, error); |
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} else {
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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bdrv_acct_done(s->bs, &req->acct); |
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g_free(req); |
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bdrv_mon_event(s->bs, BDRV_ACTION_REPORT, is_read); |
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} |
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return 1; |
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} |
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static void virtio_blk_rw_complete(void *opaque, int ret) |
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{ |
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VirtIOBlockReq *req = opaque; |
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trace_virtio_blk_rw_complete(req, ret); |
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if (ret) {
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int is_read = !(ldl_p(&req->out->type) & VIRTIO_BLK_T_OUT);
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if (virtio_blk_handle_rw_error(req, -ret, is_read))
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return;
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} |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); |
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bdrv_acct_done(req->dev->bs, &req->acct); |
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g_free(req); |
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} |
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static void virtio_blk_flush_complete(void *opaque, int ret) |
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{ |
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VirtIOBlockReq *req = opaque; |
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if (ret) {
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if (virtio_blk_handle_rw_error(req, -ret, 0)) { |
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return;
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} |
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} |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); |
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bdrv_acct_done(req->dev->bs, &req->acct); |
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g_free(req); |
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} |
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static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
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{ |
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VirtIOBlockReq *req = g_malloc(sizeof(*req));
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req->dev = s; |
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req->qiov.size = 0;
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req->next = NULL;
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return req;
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} |
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static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
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{ |
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VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
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if (req != NULL) { |
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if (!virtqueue_pop(s->vq, &req->elem)) {
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g_free(req); |
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return NULL; |
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} |
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} |
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return req;
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} |
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#ifdef __linux__
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static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
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{ |
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struct sg_io_hdr hdr;
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int ret;
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int status;
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int i;
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if ((req->dev->vdev.guest_features & (1 << VIRTIO_BLK_F_SCSI)) == 0) { |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
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g_free(req); |
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return;
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} |
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/*
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* We require at least one output segment each for the virtio_blk_outhdr
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* and the SCSI command block.
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*
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* We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
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* and the sense buffer pointer in the input segments.
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*/
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if (req->elem.out_num < 2 || req->elem.in_num < 3) { |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); |
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g_free(req); |
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return;
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} |
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/*
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* No support for bidirection commands yet.
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*/
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if (req->elem.out_num > 2 && req->elem.in_num > 3) { |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
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g_free(req); |
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return;
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} |
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/*
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* The scsi inhdr is placed in the second-to-last input segment, just
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* before the regular inhdr.
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*/
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req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base; |
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memset(&hdr, 0, sizeof(struct sg_io_hdr)); |
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hdr.interface_id = 'S';
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hdr.cmd_len = req->elem.out_sg[1].iov_len;
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hdr.cmdp = req->elem.out_sg[1].iov_base;
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hdr.dxfer_len = 0;
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if (req->elem.out_num > 2) { |
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/*
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* If there are more than the minimally required 2 output segments
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* there is write payload starting from the third iovec.
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*/
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hdr.dxfer_direction = SG_DXFER_TO_DEV; |
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hdr.iovec_count = req->elem.out_num - 2;
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for (i = 0; i < hdr.iovec_count; i++) |
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hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
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hdr.dxferp = req->elem.out_sg + 2;
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} else if (req->elem.in_num > 3) { |
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/*
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* If we have more than 3 input segments the guest wants to actually
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* read data.
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*/
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hdr.dxfer_direction = SG_DXFER_FROM_DEV; |
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hdr.iovec_count = req->elem.in_num - 3;
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for (i = 0; i < hdr.iovec_count; i++) |
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hdr.dxfer_len += req->elem.in_sg[i].iov_len; |
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hdr.dxferp = req->elem.in_sg; |
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} else {
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/*
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* Some SCSI commands don't actually transfer any data.
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*/
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hdr.dxfer_direction = SG_DXFER_NONE; |
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} |
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hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
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hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
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ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr); |
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if (ret) {
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status = VIRTIO_BLK_S_UNSUPP; |
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hdr.status = ret; |
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hdr.resid = hdr.dxfer_len; |
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} else if (hdr.status) { |
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status = VIRTIO_BLK_S_IOERR; |
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} else {
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status = VIRTIO_BLK_S_OK; |
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} |
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/*
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* From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
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* clear the masked_status field [hence status gets cleared too, see
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* block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
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* status has occurred. However they do set DRIVER_SENSE in driver_status
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* field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
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*/
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if (hdr.status == 0 && hdr.sb_len_wr > 0) { |
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hdr.status = CHECK_CONDITION; |
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} |
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stl_p(&req->scsi->errors, |
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hdr.status | (hdr.msg_status << 8) |
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(hdr.host_status << 16) | (hdr.driver_status << 24)); |
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stl_p(&req->scsi->residual, hdr.resid); |
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stl_p(&req->scsi->sense_len, hdr.sb_len_wr); |
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stl_p(&req->scsi->data_len, hdr.dxfer_len); |
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virtio_blk_req_complete(req, status); |
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g_free(req); |
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} |
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#else
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static void virtio_blk_handle_scsi(VirtIOBlockReq *req) |
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{ |
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virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP); |
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g_free(req); |
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} |
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#endif /* __linux__ */ |
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typedef struct MultiReqBuffer { |
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BlockRequest blkreq[32];
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unsigned int num_writes; |
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} MultiReqBuffer; |
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static void virtio_submit_multiwrite(BlockDriverState *bs, MultiReqBuffer *mrb) |
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{ |
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int i, ret;
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if (!mrb->num_writes) {
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return;
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} |
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ret = bdrv_aio_multiwrite(bs, mrb->blkreq, mrb->num_writes); |
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if (ret != 0) { |
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for (i = 0; i < mrb->num_writes; i++) { |
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if (mrb->blkreq[i].error) {
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virtio_blk_rw_complete(mrb->blkreq[i].opaque, -EIO); |
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} |
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} |
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} |
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mrb->num_writes = 0;
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} |
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static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb) |
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{ |
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bdrv_acct_start(req->dev->bs, &req->acct, 0, BDRV_ACCT_FLUSH);
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/*
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* Make sure all outstanding writes are posted to the backing device.
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*/
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virtio_submit_multiwrite(req->dev->bs, mrb); |
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bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req); |
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} |
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static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb) |
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{ |
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BlockRequest *blkreq; |
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uint64_t sector; |
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sector = ldq_p(&req->out->sector); |
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bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE); |
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trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
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if (sector & req->dev->sector_mask) {
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virtio_blk_rw_complete(req, -EIO); |
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return;
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} |
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if (req->qiov.size % req->dev->conf->logical_block_size) {
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virtio_blk_rw_complete(req, -EIO); |
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return;
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} |
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if (mrb->num_writes == 32) { |
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virtio_submit_multiwrite(req->dev->bs, mrb); |
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} |
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blkreq = &mrb->blkreq[mrb->num_writes]; |
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blkreq->sector = sector; |
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blkreq->nb_sectors = req->qiov.size / BDRV_SECTOR_SIZE; |
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blkreq->qiov = &req->qiov; |
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blkreq->cb = virtio_blk_rw_complete; |
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blkreq->opaque = req; |
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blkreq->error = 0;
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mrb->num_writes++; |
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} |
340 |
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static void virtio_blk_handle_read(VirtIOBlockReq *req) |
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{ |
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uint64_t sector; |
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sector = ldq_p(&req->out->sector); |
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bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ); |
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trace_virtio_blk_handle_read(req, sector, req->qiov.size / 512);
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if (sector & req->dev->sector_mask) {
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virtio_blk_rw_complete(req, -EIO); |
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return;
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} |
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if (req->qiov.size % req->dev->conf->logical_block_size) {
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virtio_blk_rw_complete(req, -EIO); |
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return;
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} |
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bdrv_aio_readv(req->dev->bs, sector, &req->qiov, |
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req->qiov.size / BDRV_SECTOR_SIZE, |
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virtio_blk_rw_complete, req); |
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} |
363 |
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static void virtio_blk_handle_request(VirtIOBlockReq *req, |
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MultiReqBuffer *mrb) |
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{ |
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uint32_t type; |
368 |
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if (req->elem.out_num < 1 || req->elem.in_num < 1) { |
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error_report("virtio-blk missing headers");
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exit(1);
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} |
373 |
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if (req->elem.out_sg[0].iov_len < sizeof(*req->out) || |
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req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) { |
376 |
error_report("virtio-blk header not in correct element");
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exit(1);
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} |
379 |
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req->out = (void *)req->elem.out_sg[0].iov_base; |
381 |
req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base; |
382 |
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383 |
type = ldl_p(&req->out->type); |
384 |
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if (type & VIRTIO_BLK_T_FLUSH) {
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386 |
virtio_blk_handle_flush(req, mrb); |
387 |
} else if (type & VIRTIO_BLK_T_SCSI_CMD) { |
388 |
virtio_blk_handle_scsi(req); |
389 |
} else if (type & VIRTIO_BLK_T_GET_ID) { |
390 |
VirtIOBlock *s = req->dev; |
391 |
|
392 |
/*
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* NB: per existing s/n string convention the string is
|
394 |
* terminated by '\0' only when shorter than buffer.
|
395 |
*/
|
396 |
strncpy(req->elem.in_sg[0].iov_base,
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s->serial ? s->serial : "",
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MIN(req->elem.in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES));
|
399 |
virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); |
400 |
g_free(req); |
401 |
} else if (type & VIRTIO_BLK_T_OUT) { |
402 |
qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
|
403 |
req->elem.out_num - 1);
|
404 |
virtio_blk_handle_write(req, mrb); |
405 |
} else {
|
406 |
qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
|
407 |
req->elem.in_num - 1);
|
408 |
virtio_blk_handle_read(req); |
409 |
} |
410 |
} |
411 |
|
412 |
static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) |
413 |
{ |
414 |
VirtIOBlock *s = to_virtio_blk(vdev); |
415 |
VirtIOBlockReq *req; |
416 |
MultiReqBuffer mrb = { |
417 |
.num_writes = 0,
|
418 |
}; |
419 |
|
420 |
while ((req = virtio_blk_get_request(s))) {
|
421 |
virtio_blk_handle_request(req, &mrb); |
422 |
} |
423 |
|
424 |
virtio_submit_multiwrite(s->bs, &mrb); |
425 |
|
426 |
/*
|
427 |
* FIXME: Want to check for completions before returning to guest mode,
|
428 |
* so cached reads and writes are reported as quickly as possible. But
|
429 |
* that should be done in the generic block layer.
|
430 |
*/
|
431 |
} |
432 |
|
433 |
static void virtio_blk_dma_restart_bh(void *opaque) |
434 |
{ |
435 |
VirtIOBlock *s = opaque; |
436 |
VirtIOBlockReq *req = s->rq; |
437 |
MultiReqBuffer mrb = { |
438 |
.num_writes = 0,
|
439 |
}; |
440 |
|
441 |
qemu_bh_delete(s->bh); |
442 |
s->bh = NULL;
|
443 |
|
444 |
s->rq = NULL;
|
445 |
|
446 |
while (req) {
|
447 |
virtio_blk_handle_request(req, &mrb); |
448 |
req = req->next; |
449 |
} |
450 |
|
451 |
virtio_submit_multiwrite(s->bs, &mrb); |
452 |
} |
453 |
|
454 |
static void virtio_blk_dma_restart_cb(void *opaque, int running, |
455 |
RunState state) |
456 |
{ |
457 |
VirtIOBlock *s = opaque; |
458 |
|
459 |
if (!running)
|
460 |
return;
|
461 |
|
462 |
if (!s->bh) {
|
463 |
s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s); |
464 |
qemu_bh_schedule(s->bh); |
465 |
} |
466 |
} |
467 |
|
468 |
static void virtio_blk_reset(VirtIODevice *vdev) |
469 |
{ |
470 |
/*
|
471 |
* This should cancel pending requests, but can't do nicely until there
|
472 |
* are per-device request lists.
|
473 |
*/
|
474 |
bdrv_drain_all(); |
475 |
} |
476 |
|
477 |
/* coalesce internal state, copy to pci i/o region 0
|
478 |
*/
|
479 |
static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) |
480 |
{ |
481 |
VirtIOBlock *s = to_virtio_blk(vdev); |
482 |
struct virtio_blk_config blkcfg;
|
483 |
uint64_t capacity; |
484 |
int cylinders, heads, secs;
|
485 |
int blk_size = s->conf->logical_block_size;
|
486 |
|
487 |
bdrv_get_geometry(s->bs, &capacity); |
488 |
bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs); |
489 |
memset(&blkcfg, 0, sizeof(blkcfg)); |
490 |
stq_raw(&blkcfg.capacity, capacity); |
491 |
stl_raw(&blkcfg.seg_max, 128 - 2); |
492 |
stw_raw(&blkcfg.cylinders, cylinders); |
493 |
stl_raw(&blkcfg.blk_size, blk_size); |
494 |
stw_raw(&blkcfg.min_io_size, s->conf->min_io_size / blk_size); |
495 |
stw_raw(&blkcfg.opt_io_size, s->conf->opt_io_size / blk_size); |
496 |
blkcfg.heads = heads; |
497 |
blkcfg.sectors = secs & ~s->sector_mask; |
498 |
blkcfg.size_max = 0;
|
499 |
blkcfg.physical_block_exp = get_physical_block_exp(s->conf); |
500 |
blkcfg.alignment_offset = 0;
|
501 |
memcpy(config, &blkcfg, sizeof(struct virtio_blk_config)); |
502 |
} |
503 |
|
504 |
static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
|
505 |
{ |
506 |
VirtIOBlock *s = to_virtio_blk(vdev); |
507 |
|
508 |
features |= (1 << VIRTIO_BLK_F_SEG_MAX);
|
509 |
features |= (1 << VIRTIO_BLK_F_GEOMETRY);
|
510 |
features |= (1 << VIRTIO_BLK_F_TOPOLOGY);
|
511 |
features |= (1 << VIRTIO_BLK_F_BLK_SIZE);
|
512 |
|
513 |
if (bdrv_enable_write_cache(s->bs))
|
514 |
features |= (1 << VIRTIO_BLK_F_WCACHE);
|
515 |
|
516 |
if (bdrv_is_read_only(s->bs))
|
517 |
features |= 1 << VIRTIO_BLK_F_RO;
|
518 |
|
519 |
return features;
|
520 |
} |
521 |
|
522 |
static void virtio_blk_save(QEMUFile *f, void *opaque) |
523 |
{ |
524 |
VirtIOBlock *s = opaque; |
525 |
VirtIOBlockReq *req = s->rq; |
526 |
|
527 |
virtio_save(&s->vdev, f); |
528 |
|
529 |
while (req) {
|
530 |
qemu_put_sbyte(f, 1);
|
531 |
qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
532 |
req = req->next; |
533 |
} |
534 |
qemu_put_sbyte(f, 0);
|
535 |
} |
536 |
|
537 |
static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) |
538 |
{ |
539 |
VirtIOBlock *s = opaque; |
540 |
|
541 |
if (version_id != 2) |
542 |
return -EINVAL;
|
543 |
|
544 |
virtio_load(&s->vdev, f); |
545 |
while (qemu_get_sbyte(f)) {
|
546 |
VirtIOBlockReq *req = virtio_blk_alloc_request(s); |
547 |
qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem)); |
548 |
req->next = s->rq; |
549 |
s->rq = req; |
550 |
|
551 |
virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr, |
552 |
req->elem.in_num, 1);
|
553 |
virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr, |
554 |
req->elem.out_num, 0);
|
555 |
} |
556 |
|
557 |
return 0; |
558 |
} |
559 |
|
560 |
static void virtio_blk_resize(void *opaque) |
561 |
{ |
562 |
VirtIOBlock *s = opaque; |
563 |
|
564 |
virtio_notify_config(&s->vdev); |
565 |
} |
566 |
|
567 |
static const BlockDevOps virtio_block_ops = { |
568 |
.resize_cb = virtio_blk_resize, |
569 |
}; |
570 |
|
571 |
VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf, |
572 |
char **serial)
|
573 |
{ |
574 |
VirtIOBlock *s; |
575 |
int cylinders, heads, secs;
|
576 |
static int virtio_blk_id; |
577 |
DriveInfo *dinfo; |
578 |
|
579 |
if (!conf->bs) {
|
580 |
error_report("drive property not set");
|
581 |
return NULL; |
582 |
} |
583 |
if (!bdrv_is_inserted(conf->bs)) {
|
584 |
error_report("Device needs media, but drive is empty");
|
585 |
return NULL; |
586 |
} |
587 |
|
588 |
if (!*serial) {
|
589 |
/* try to fall back to value set with legacy -drive serial=... */
|
590 |
dinfo = drive_get_by_blockdev(conf->bs); |
591 |
if (*dinfo->serial) {
|
592 |
*serial = strdup(dinfo->serial); |
593 |
} |
594 |
} |
595 |
|
596 |
s = (VirtIOBlock *)virtio_common_init("virtio-blk", VIRTIO_ID_BLOCK,
|
597 |
sizeof(struct virtio_blk_config), |
598 |
sizeof(VirtIOBlock));
|
599 |
|
600 |
s->vdev.get_config = virtio_blk_update_config; |
601 |
s->vdev.get_features = virtio_blk_get_features; |
602 |
s->vdev.reset = virtio_blk_reset; |
603 |
s->bs = conf->bs; |
604 |
s->conf = conf; |
605 |
s->serial = *serial; |
606 |
s->rq = NULL;
|
607 |
s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
|
608 |
bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs); |
609 |
|
610 |
s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
|
611 |
|
612 |
qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s); |
613 |
s->qdev = dev; |
614 |
register_savevm(dev, "virtio-blk", virtio_blk_id++, 2, |
615 |
virtio_blk_save, virtio_blk_load, s); |
616 |
bdrv_set_dev_ops(s->bs, &virtio_block_ops, s); |
617 |
bdrv_set_buffer_alignment(s->bs, conf->logical_block_size); |
618 |
|
619 |
bdrv_iostatus_enable(s->bs); |
620 |
add_boot_device_path(conf->bootindex, dev, "/disk@0,0");
|
621 |
|
622 |
return &s->vdev;
|
623 |
} |
624 |
|
625 |
void virtio_blk_exit(VirtIODevice *vdev)
|
626 |
{ |
627 |
VirtIOBlock *s = to_virtio_blk(vdev); |
628 |
unregister_savevm(s->qdev, "virtio-blk", s);
|
629 |
virtio_cleanup(vdev); |
630 |
} |