diff options
| author | Christoph Hellwig <hch@lst.de> | 2009-09-04 19:02:23 +0200 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2009-09-11 10:19:46 -0500 |
| commit | aa659be3dc2aa86614bcf6960f9d4af2a4362156 (patch) | |
| tree | 86739e8a381966394455528f26880d5de82a436b | |
| parent | b0484ae464dcd8ee7439c4257b2f40d6b0e007dd (diff) | |
virtio-blk: add volatile writecache feature
Add a new VIRTIO_BLK_F_WCACHE feature to virtio-blk to indicate that we have
a volatile write cache that needs controlled flushing. Implement a
VIRTIO_BLK_T_FLUSH operation to flush it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
| -rw-r--r-- | hw/virtio-blk.c | 24 | ||||
| -rw-r--r-- | hw/virtio-blk.h | 4 |
2 files changed, 27 insertions, 1 deletions
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c index 8cbb1efd5d..2d6d71afa1 100644 --- a/hw/virtio-blk.c +++ b/hw/virtio-blk.c @@ -130,6 +130,13 @@ static void virtio_blk_rw_complete(void *opaque, int ret) virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); } +static void virtio_blk_flush_complete(void *opaque, int ret) +{ + VirtIOBlockReq *req = opaque; + + virtio_blk_req_complete(req, ret ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK); +} + static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) { VirtIOBlockReq *req = qemu_mallocz(sizeof(*req)); @@ -268,6 +275,16 @@ static void do_multiwrite(BlockDriverState *bs, BlockRequest *blkreq, } } +static void virtio_blk_handle_flush(VirtIOBlockReq *req) +{ + BlockDriverAIOCB *acb; + + acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req); + if (!acb) { + virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR); + } +} + static void virtio_blk_handle_write(BlockRequest *blkreq, int *num_writes, VirtIOBlockReq *req, BlockDriverState **old_bs) { @@ -323,7 +340,9 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) req->out = (void *)req->elem.out_sg[0].iov_base; req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base; - if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { + if (req->out->type & VIRTIO_BLK_T_FLUSH) { + virtio_blk_handle_flush(req); + } else if (req->out->type & VIRTIO_BLK_T_SCSI_CMD) { virtio_blk_handle_scsi(req); } else if (req->out->type & VIRTIO_BLK_T_OUT) { qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1], @@ -417,6 +436,9 @@ static uint32_t virtio_blk_get_features(VirtIODevice *vdev) features |= (1 << VIRTIO_BLK_F_SEG_MAX); features |= (1 << VIRTIO_BLK_F_GEOMETRY); + + if (bdrv_enable_write_cache(s->bs)) + features |= (1 << VIRTIO_BLK_F_WCACHE); #ifdef __linux__ features |= (1 << VIRTIO_BLK_F_SCSI); #endif diff --git a/hw/virtio-blk.h b/hw/virtio-blk.h index 1be4342706..23ad74caec 100644 --- a/hw/virtio-blk.h +++ b/hw/virtio-blk.h @@ -31,6 +31,7 @@ #define VIRTIO_BLK_F_BLK_SIZE 6 /* Block size of disk is available*/ #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */ #define VIRTIO_BLK_F_IDENTIFY 8 /* ATA IDENTIFY supported */ +#define VIRTIO_BLK_F_WCACHE 9 /* write cache enabled */ #define VIRTIO_BLK_ID_LEN 256 /* length of identify u16 array */ #define VIRTIO_BLK_ID_SN 10 /* start of char * serial# */ @@ -55,6 +56,9 @@ struct virtio_blk_config /* This bit says it's a scsi command, not an actual read or write. */ #define VIRTIO_BLK_T_SCSI_CMD 2 +/* Flush the volatile write cache */ +#define VIRTIO_BLK_T_FLUSH 4 + /* Barrier before this op. */ #define VIRTIO_BLK_T_BARRIER 0x80000000 |