Start with a clean slate, a virtio-blk device that supports virtio
lifecycle operations and configuration but doesn't do any actual I/O.
The I/O is going to happen in a separate optimized data plane thread.
Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxxxxxxxxxx>
---
hw/virtio-blk.c | 496 +------------------------------------------------------
1 file changed, 3 insertions(+), 493 deletions(-)
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 49990f8..a627427 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -16,18 +16,12 @@
#include "trace.h"
#include "blockdev.h"
#include "virtio-blk.h"
-#include "scsi-defs.h"
-#ifdef __linux__
-# include <scsi/sg.h>
-#endif
typedef struct VirtIOBlock
{
VirtIODevice vdev;
BlockDriverState *bs;
VirtQueue *vq;
- void *rq;
- QEMUBH *bh;
BlockConf *conf;
char *serial;
unsigned short sector_mask;
@@ -39,439 +33,11 @@ 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;
- struct virtio_scsi_inhdr *scsi;
- QEMUIOVector qiov;
- struct VirtIOBlockReq *next;
- BlockAcctCookie acct;
-} VirtIOBlockReq;
-
-static void virtio_blk_req_complete(VirtIOBlockReq *req, int status)
-{
- VirtIOBlock *s = req->dev;
-
- trace_virtio_blk_req_complete(req, status);
-
- stb_p(&req->in->status, status);
- virtqueue_push(s->vq, &req->elem, req->qiov.size + sizeof(*req->in));
- virtio_notify(&s->vdev, s->vq);
-}
-
-static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
- int is_read)
-{
- BlockErrorAction action = bdrv_get_on_error(req->dev->bs, is_read);
- VirtIOBlock *s = req->dev;
-
- if (action == BLOCK_ERR_IGNORE) {
- bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_IGNORE, is_read);
- return 0;
- }
-
- if ((error == ENOSPC && action == BLOCK_ERR_STOP_ENOSPC)
- || action == BLOCK_ERR_STOP_ANY) {
- req->next = s->rq;
- s->rq = req;
- bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_STOP, is_read);
- vm_stop(RUN_STATE_IO_ERROR);
- bdrv_iostatus_set_err(s->bs, error);
- } else {
- virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
- bdrv_acct_done(s->bs, &req->acct);
- g_free(req);
- bdrv_emit_qmp_error_event(s->bs, BDRV_ACTION_REPORT, is_read);
- }
-
- return 1;
-}
-
-static void virtio_blk_rw_complete(void *opaque, int ret)
-{
- VirtIOBlockReq *req = opaque;
-
- trace_virtio_blk_rw_complete(req, ret);
-
- if (ret) {
- int is_read = !(ldl_p(&req->out->type) & VIRTIO_BLK_T_OUT);
- if (virtio_blk_handle_rw_error(req, -ret, is_read))
- return;
- }
-
- virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
- bdrv_acct_done(req->dev->bs, &req->acct);
- g_free(req);
-}
-
-static void virtio_blk_flush_complete(void *opaque, int ret)
-{
- VirtIOBlockReq *req = opaque;
-
- if (ret) {
- if (virtio_blk_handle_rw_error(req, -ret, 0)) {
- return;
- }
- }
-
- virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
- bdrv_acct_done(req->dev->bs, &req->acct);
- g_free(req);
-}
-
-static VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s)
-{
- VirtIOBlockReq *req = g_malloc(sizeof(*req));
- req->dev = s;
- req->qiov.size = 0;
- req->next = NULL;
- return req;
-}
-
-static VirtIOBlockReq *virtio_blk_get_request(VirtIOBlock *s)
-{
- VirtIOBlockReq *req = virtio_blk_alloc_request(s);
-
- if (req != NULL) {
- if (!virtqueue_pop(s->vq, &req->elem)) {
- g_free(req);
- return NULL;
- }
- }
-
- return req;
-}
-
-#ifdef __linux__
-static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
-{
- struct sg_io_hdr hdr;
- int ret;
- int status;
- int i;
-
- if ((req->dev->vdev.guest_features & (1 << VIRTIO_BLK_F_SCSI)) == 0) {
- virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
- g_free(req);
- return;
- }
-
- /*
- * We require at least one output segment each for the virtio_blk_outhdr
- * and the SCSI command block.
- *
- * We also at least require the virtio_blk_inhdr, the virtio_scsi_inhdr
- * and the sense buffer pointer in the input segments.
- */
- if (req->elem.out_num < 2 || req->elem.in_num < 3) {
- virtio_blk_req_complete(req, VIRTIO_BLK_S_IOERR);
- g_free(req);
- return;
- }
-
- /*
- * No support for bidirection commands yet.
- */
- if (req->elem.out_num > 2 && req->elem.in_num > 3) {
- virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
- g_free(req);
- return;
- }
-
- /*
- * The scsi inhdr is placed in the second-to-last input segment, just
- * before the regular inhdr.
- */
- req->scsi = (void *)req->elem.in_sg[req->elem.in_num - 2].iov_base;
-
- memset(&hdr, 0, sizeof(struct sg_io_hdr));
- hdr.interface_id = 'S';
- hdr.cmd_len = req->elem.out_sg[1].iov_len;
- hdr.cmdp = req->elem.out_sg[1].iov_base;
- hdr.dxfer_len = 0;
-
- if (req->elem.out_num > 2) {
- /*
- * If there are more than the minimally required 2 output segments
- * there is write payload starting from the third iovec.
- */
- hdr.dxfer_direction = SG_DXFER_TO_DEV;
- hdr.iovec_count = req->elem.out_num - 2;
-
- for (i = 0; i < hdr.iovec_count; i++)
- hdr.dxfer_len += req->elem.out_sg[i + 2].iov_len;
-
- hdr.dxferp = req->elem.out_sg + 2;
-
- } else if (req->elem.in_num > 3) {
- /*
- * If we have more than 3 input segments the guest wants to actually
- * read data.
- */
- hdr.dxfer_direction = SG_DXFER_FROM_DEV;
- hdr.iovec_count = req->elem.in_num - 3;
- for (i = 0; i < hdr.iovec_count; i++)
- hdr.dxfer_len += req->elem.in_sg[i].iov_len;
-
- hdr.dxferp = req->elem.in_sg;
- } else {
- /*
- * Some SCSI commands don't actually transfer any data.
- */
- hdr.dxfer_direction = SG_DXFER_NONE;
- }
-
- hdr.sbp = req->elem.in_sg[req->elem.in_num - 3].iov_base;
- hdr.mx_sb_len = req->elem.in_sg[req->elem.in_num - 3].iov_len;
-
- ret = bdrv_ioctl(req->dev->bs, SG_IO, &hdr);
- if (ret) {
- status = VIRTIO_BLK_S_UNSUPP;
- hdr.status = ret;
- hdr.resid = hdr.dxfer_len;
- } else if (hdr.status) {
- status = VIRTIO_BLK_S_IOERR;
- } else {
- status = VIRTIO_BLK_S_OK;
- }
-
- /*
- * From SCSI-Generic-HOWTO: "Some lower level drivers (e.g. ide-scsi)
- * clear the masked_status field [hence status gets cleared too, see
- * block/scsi_ioctl.c] even when a CHECK_CONDITION or COMMAND_TERMINATED
- * status has occurred. However they do set DRIVER_SENSE in driver_status
- * field. Also a (sb_len_wr > 0) indicates there is a sense buffer.
- */
- if (hdr.status == 0 && hdr.sb_len_wr > 0) {
- hdr.status = CHECK_CONDITION;
- }
-
- stl_p(&req->scsi->errors,
- hdr.status | (hdr.msg_status << 8) |
- (hdr.host_status << 16) | (hdr.driver_status << 24));
- stl_p(&req->scsi->residual, hdr.resid);
- stl_p(&req->scsi->sense_len, hdr.sb_len_wr);
- stl_p(&req->scsi->data_len, hdr.dxfer_len);
-
- virtio_blk_req_complete(req, status);
- g_free(req);
-}
-#else
-static void virtio_blk_handle_scsi(VirtIOBlockReq *req)
-{
- virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
- g_free(req);
-}
-#endif /* __linux__ */
-
-typedef struct MultiReqBuffer {
- BlockRequest blkreq[32];
- unsigned int num_writes;
-} MultiReqBuffer;
-
-static void virtio_submit_multiwrite(BlockDriverState *bs, MultiReqBuffer *mrb)
-{
- int i, ret;
-
- if (!mrb->num_writes) {
- return;
- }
-
- ret = bdrv_aio_multiwrite(bs, mrb->blkreq, mrb->num_writes);
- if (ret != 0) {
- for (i = 0; i < mrb->num_writes; i++) {
- if (mrb->blkreq[i].error) {
- virtio_blk_rw_complete(mrb->blkreq[i].opaque, -EIO);
- }
- }
- }
-
- mrb->num_writes = 0;
-}
-
-static void virtio_blk_handle_flush(VirtIOBlockReq *req, MultiReqBuffer *mrb)
-{
- bdrv_acct_start(req->dev->bs, &req->acct, 0, BDRV_ACCT_FLUSH);
-
- /*
- * Make sure all outstanding writes are posted to the backing device.
- */
- virtio_submit_multiwrite(req->dev->bs, mrb);
- bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
-}
-
-static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
-{
- BlockRequest *blkreq;
- uint64_t sector;
-
- sector = ldq_p(&req->out->sector);
-
- bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_WRITE);
-
- trace_virtio_blk_handle_write(req, sector, req->qiov.size / 512);
-
- if (sector & req->dev->sector_mask) {
- virtio_blk_rw_complete(req, -EIO);
- return;
- }
- if (req->qiov.size % req->dev->conf->logical_block_size) {
- virtio_blk_rw_complete(req, -EIO);
- return;
- }
-
- if (mrb->num_writes == 32) {
- virtio_submit_multiwrite(req->dev->bs, mrb);
- }
-
- blkreq = &mrb->blkreq[mrb->num_writes];
- blkreq->sector = sector;
- blkreq->nb_sectors = req->qiov.size / BDRV_SECTOR_SIZE;
- blkreq->qiov = &req->qiov;
- blkreq->cb = virtio_blk_rw_complete;
- blkreq->opaque = req;
- blkreq->error = 0;
-
- mrb->num_writes++;
-}
-
-static void virtio_blk_handle_read(VirtIOBlockReq *req)
-{
- uint64_t sector;
-
- sector = ldq_p(&req->out->sector);
-
- bdrv_acct_start(req->dev->bs, &req->acct, req->qiov.size, BDRV_ACCT_READ);
-
- trace_virtio_blk_handle_read(req, sector, req->qiov.size / 512);
-
- if (sector & req->dev->sector_mask) {
- virtio_blk_rw_complete(req, -EIO);
- return;
- }
- if (req->qiov.size % req->dev->conf->logical_block_size) {
- virtio_blk_rw_complete(req, -EIO);
- return;
- }
- bdrv_aio_readv(req->dev->bs, sector, &req->qiov,
- req->qiov.size / BDRV_SECTOR_SIZE,
- virtio_blk_rw_complete, req);
-}
-
-static void virtio_blk_handle_request(VirtIOBlockReq *req,
- MultiReqBuffer *mrb)
-{
- uint32_t type;
-
- if (req->elem.out_num < 1 || req->elem.in_num < 1) {
- error_report("virtio-blk missing headers");
- 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)) {
- error_report("virtio-blk header not in correct element");
- 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;
-
- type = ldl_p(&req->out->type);
-
- if (type & VIRTIO_BLK_T_FLUSH) {
- virtio_blk_handle_flush(req, mrb);
- } else if (type & VIRTIO_BLK_T_SCSI_CMD) {
- virtio_blk_handle_scsi(req);
- } else if (type & VIRTIO_BLK_T_GET_ID) {
- VirtIOBlock *s = req->dev;
-
- /*
- * NB: per existing s/n string convention the string is
- * terminated by '\0' only when shorter than buffer.
- */
- strncpy(req->elem.in_sg[0].iov_base,
- s->serial ? s->serial : "",
- MIN(req->elem.in_sg[0].iov_len, VIRTIO_BLK_ID_BYTES));
- virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
- g_free(req);
- } else if (type & VIRTIO_BLK_T_OUT) {
- qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
- req->elem.out_num - 1);
- virtio_blk_handle_write(req, mrb);
- } else {
- qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
- req->elem.in_num - 1);
- virtio_blk_handle_read(req);
- }
-}
-
static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
- VirtIOBlock *s = to_virtio_blk(vdev);
- VirtIOBlockReq *req;
- MultiReqBuffer mrb = {
- .num_writes = 0,
- };
-
- while ((req = virtio_blk_get_request(s))) {
- virtio_blk_handle_request(req, &mrb);
- }
-
- virtio_submit_multiwrite(s->bs, &mrb);
-
- /*
- * 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_dma_restart_bh(void *opaque)
-{
- VirtIOBlock *s = opaque;
- VirtIOBlockReq *req = s->rq;
- MultiReqBuffer mrb = {
- .num_writes = 0,
- };
-
- qemu_bh_delete(s->bh);
- s->bh = NULL;
-
- s->rq = NULL;
-
- while (req) {
- virtio_blk_handle_request(req, &mrb);
- req = req->next;
- }
-
- virtio_submit_multiwrite(s->bs, &mrb);
-}
-
-static void virtio_blk_dma_restart_cb(void *opaque, int running,
- RunState state)
-{
- VirtIOBlock *s = opaque;
-
- if (!running)
- return;
-
- if (!s->bh) {
- s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s);
- qemu_bh_schedule(s->bh);
- }
-}
-
-static void virtio_blk_reset(VirtIODevice *vdev)
-{
- /*
- * This should cancel pending requests, but can't do nicely until there
- * are per-device request lists.
- */
- bdrv_drain_all();
+ fprintf(stderr, "virtio_blk_handle_output: should never get here,"
+ "data plane thread should process requests\n");
+ exit(1);
}
/* coalesce internal state, copy to pci i/o region 0
@@ -519,61 +85,11 @@ static uint32_t virtio_blk_get_features(VirtIODevice *vdev, uint32_t features)
return features;
}
-static void virtio_blk_save(QEMUFile *f, void *opaque)
-{
- VirtIOBlock *s = opaque;
- VirtIOBlockReq *req = s->rq;
-
- virtio_save(&s->vdev, f);
-
- while (req) {
- qemu_put_sbyte(f, 1);
- qemu_put_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
- req = req->next;
- }
- qemu_put_sbyte(f, 0);
-}
-
-static int virtio_blk_load(QEMUFile *f, void *opaque, int version_id)
-{
- VirtIOBlock *s = opaque;
-
- if (version_id != 2)
- return -EINVAL;
-
- virtio_load(&s->vdev, f);
- while (qemu_get_sbyte(f)) {
- VirtIOBlockReq *req = virtio_blk_alloc_request(s);
- qemu_get_buffer(f, (unsigned char*)&req->elem, sizeof(req->elem));
- req->next = s->rq;
- s->rq = req;
-
- virtqueue_map_sg(req->elem.in_sg, req->elem.in_addr,
- req->elem.in_num, 1);
- virtqueue_map_sg(req->elem.out_sg, req->elem.out_addr,
- req->elem.out_num, 0);
- }
-
- return 0;
-}
-
-static void virtio_blk_resize(void *opaque)
-{
- VirtIOBlock *s = opaque;
-
- virtio_notify_config(&s->vdev);
-}
-
-static const BlockDevOps virtio_block_ops = {
- .resize_cb = virtio_blk_resize,
-};
-
VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf,
char **serial)
{
VirtIOBlock *s;
int cylinders, heads, secs;
- static int virtio_blk_id;
DriveInfo *dinfo;
if (!conf->bs) {
@@ -599,21 +115,15 @@ VirtIODevice *virtio_blk_init(DeviceState *dev, BlockConf *conf,
s->vdev.get_config = virtio_blk_update_config;
s->vdev.get_features = virtio_blk_get_features;
- s->vdev.reset = virtio_blk_reset;
s->bs = conf->bs;
s->conf = conf;
s->serial = *serial;
- s->rq = NULL;
s->sector_mask = (s->conf->logical_block_size / BDRV_SECTOR_SIZE) - 1;
bdrv_guess_geometry(s->bs, &cylinders, &heads, &secs);
s->vq = virtio_add_queue(&s->vdev, 128, virtio_blk_handle_output);
- qemu_add_vm_change_state_handler(virtio_blk_dma_restart_cb, s);
s->qdev = dev;
- register_savevm(dev, "virtio-blk", virtio_blk_id++, 2,
- virtio_blk_save, virtio_blk_load, s);
- bdrv_set_dev_ops(s->bs, &virtio_block_ops, s);
bdrv_set_buffer_alignment(s->bs, conf->logical_block_size);
bdrv_iostatus_enable(s->bs);
--
1.7.10.4
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