diff options
Diffstat (limited to 'hw/virtio-blk.c')
| -rw-r--r-- | hw/virtio-blk.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c new file mode 100644 index 0000000000..91b90d2030 --- /dev/null +++ b/hw/virtio-blk.c @@ -0,0 +1,248 @@ +/* + * Virtio Block Device + * + * Copyright IBM, Corp. 2007 + * + * Authors: + * Anthony Liguori <aliguori@us.ibm.com> + * + * This work is licensed under the terms of the GNU GPL, version 2. See + * the COPYING file in the top-level directory. + * + */ + +#include "virtio-blk.h" +#include "block_int.h" + +typedef struct VirtIOBlock +{ + VirtIODevice vdev; + BlockDriverState *bs; + VirtQueue *vq; +} VirtIOBlock; + +static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev) +{ + return (VirtIOBlock *)vdev; +} + +typedef struct VirtIOBlockReq +{ + VirtIOBlock *dev; + VirtQueueElement elem; + struct virtio_blk_inhdr *in; + struct virtio_blk_outhdr *out; + size_t size; + uint8_t *buffer; +} VirtIOBlockReq; + +static void virtio_blk_rw_complete(void *opaque, int ret) +{ + VirtIOBlockReq *req = opaque; + VirtIOBlock *s = req->dev; + + /* Copy read data to the guest */ + if (!ret && !(req->out->type & VIRTIO_BLK_T_OUT)) { + size_t offset = 0; + int i; + + for (i = 0; i < req->elem.in_num - 1; i++) { + size_t len; + + /* Be pretty defensive wrt malicious guests */ + len = MIN(req->elem.in_sg[i].iov_len, + req->size - offset); + + memcpy(req->elem.in_sg[i].iov_base, + req->buffer + offset, + len); + offset += len; + } + } + + req->in->status = ret ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK; + virtqueue_push(s->vq, &req->elem, req->size + sizeof(*req->in)); + virtio_notify(&s->vdev, s->vq); + + qemu_free(req->buffer); + qemu_free(req); +} + +static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s) +{ + VirtIOBlockReq *req; + + req = qemu_mallocz(sizeof(*req)); + if (req == NULL) + return NULL; + + req->dev = s; + if (!virtqueue_pop(s->vq, &req->elem)) { + qemu_free(req); + return NULL; + } + + return req; +} + +static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq) +{ + VirtIOBlock *s = to_virtio_blk(vdev); + VirtIOBlockReq *req; + + while ((req = virtio_blk_get_request(s))) { + int i; + + if (req->elem.out_num < 1 || req->elem.in_num < 1) { + fprintf(stderr, "virtio-blk missing headers\n"); + exit(1); + } + + if (req->elem.out_sg[0].iov_len < sizeof(*req->out) || + req->elem.in_sg[req->elem.in_num - 1].iov_len < sizeof(*req->in)) { + fprintf(stderr, "virtio-blk header not in correct element\n"); + exit(1); + } + + 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) { + unsigned int len = sizeof(*req->in); + + req->in->status = VIRTIO_BLK_S_UNSUPP; + virtqueue_push(vq, &req->elem, len); + virtio_notify(vdev, vq); + qemu_free(req); + } else if (req->out->type & VIRTIO_BLK_T_OUT) { + size_t offset; + + for (i = 1; i < req->elem.out_num; i++) + req->size += req->elem.out_sg[i].iov_len; + + req->buffer = qemu_memalign(512, req->size); + if (req->buffer == NULL) { + qemu_free(req); + break; + } + + /* We copy the data from the SG list to avoid splitting up the request. This helps + performance a lot until we can pass full sg lists as AIO operations */ + offset = 0; + for (i = 1; i < req->elem.out_num; i++) { + size_t len; + + len = MIN(req->elem.out_sg[i].iov_len, + req->size - offset); + memcpy(req->buffer + offset, + req->elem.out_sg[i].iov_base, + len); + offset += len; + } + + bdrv_aio_write(s->bs, req->out->sector, + req->buffer, + req->size / 512, + virtio_blk_rw_complete, + req); + } else { + for (i = 0; i < req->elem.in_num - 1; i++) + req->size += req->elem.in_sg[i].iov_len; + + req->buffer = qemu_memalign(512, req->size); + if (req->buffer == NULL) { + qemu_free(req); + break; + } + + bdrv_aio_read(s->bs, req->out->sector, + req->buffer, + req->size / 512, + virtio_blk_rw_complete, + req); + } + } + /* + * FIXME: Want to check for completions before returning to guest mode, + * so cached reads and writes are reported as quickly as possible. But + * that should be done in the generic block layer. + */ +} + +static void virtio_blk_reset(VirtIODevice *vdev) +{ + /* + * This should cancel pending requests, but can't do nicely until there + * are per-device request lists. + */ + qemu_aio_flush(); +} + +static void virtio_blk_update_config(VirtIODevice *vdev, uint8_t *config) +{ + VirtIOBlock *s = to_virtio_blk(vdev); + struct virtio_blk_config blkcfg; + uint64_t capacity; + int cylinders, heads, secs; + + bdrv_get_geometry(s->bs, &capacity); + bdrv_get_geometry_hint(s->bs, &cylinders, &heads, &secs); + stq_raw(&blkcfg.capacity, capacity); + stl_raw(&blkcfg.seg_max, 128 - 2); + stw_raw(&blkcfg.cylinders, cylinders); + blkcfg.heads = heads; + blkcfg.sectors = secs; + memcpy(config, &blkcfg, sizeof(blkcfg)); +} + +static uint32_t virtio_blk_get_features(VirtIODevice *vdev) +{ + return (1 << VIRTIO_BLK_F_SEG_MAX | 1 << VIRTIO_BLK_F_GEOMETRY); +} + +static void virtio_blk_save(QEMUFile *f, void *opaque) +{ + VirtIOBlock *s = opaque; + virtio_save(&s->vdev, f); +} + +static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id) +{ + VirtIOBlock *s = opaque; + + if (version_id != 1) + return -EINVAL; + + virtio_load(&s->vdev, f); + + return 0; +} + +void *virtio_blk_init(PCIBus *bus, uint16_t vendor, uint16_t device, + BlockDriverState *bs) +{ + VirtIOBlock *s; + int cylinders, heads, secs; + static int virtio_blk_id; + + s = (VirtIOBlock *)virtio_init_pci(bus, "virtio-blk", vendor, device, + 0, VIRTIO_ID_BLOCK, + 0x01, 0x80, 0x00, + sizeof(struct virtio_blk_config), sizeof(VirtIOBlock)); + if (!s) + return NULL; + + s->vdev.get_config = virtio_blk_update_config; + s->vdev.get_features = virtio_blk_get_features; + s->vdev.reset = virtio_blk_reset; + s->bs = bs; + bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs); + bdrv_set_geometry_hint(s->bs, cylinders, heads, secs); + + s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output); + + register_savevm("virtio-blk", virtio_blk_id++, 1, + virtio_blk_save, virtio_blk_load, s); + + return s; +} |