All these errors are caused by a buggy guest: QEMU should not exit.
With this patch, if virtio_blk_handle_request() detects a buggy request, it
marks the device as broken and returns an error to the caller so it takes
appropriate action.
In the case of virtio_blk_handle_vq(), we detach the request from the
virtqueue, free its allocated memory and stop popping new requests.
We don't need to bother about multireq since virtio_blk_handle_request()
errors out early and mrb.num_reqs == 0.
In the case of virtio_blk_dma_restart_bh(), we need to detach and free all
queued requests as well.
Signed-off-by: Greg Kurz <gr...@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
---
v4: - added Stefan's R-b tag
---
hw/block/virtio-blk.c | 38 ++++++++++++++++++++++++++++----------
1 file changed, 28 insertions(+), 10 deletions(-)
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index bbacd562cefb..0ddd7fbbe54f 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -468,30 +468,32 @@ static bool virtio_blk_sect_range_ok(VirtIOBlock *dev,
return true;
}
-static void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
+static int virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb)
{
uint32_t type;
struct iovec *in_iov = req->elem.in_sg;
struct iovec *iov = req->elem.out_sg;
unsigned in_num = req->elem.in_num;
unsigned out_num = req->elem.out_num;
+ VirtIOBlock *s = req->dev;
+ VirtIODevice *vdev = VIRTIO_DEVICE(s);
if (req->elem.out_num < 1 || req->elem.in_num < 1) {
- error_report("virtio-blk missing headers");
- exit(1);
+ virtio_error(vdev, "virtio-blk missing headers");
+ return -1;
}
if (unlikely(iov_to_buf(iov, out_num, 0, &req->out,
sizeof(req->out)) != sizeof(req->out))) {
- error_report("virtio-blk request outhdr too short");
- exit(1);
+ virtio_error(vdev, "virtio-blk request outhdr too short");
+ return -1;
}
iov_discard_front(&iov, &out_num, sizeof(req->out));
if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
- error_report("virtio-blk request inhdr too short");
- exit(1);
+ virtio_error(vdev, "virtio-blk request inhdr too short");
+ return -1;
}
/* We always touch the last byte, so just see how big in_iov is. */
@@ -529,7 +531,7 @@ static void virtio_blk_handle_request(VirtIOBlockReq *req,
MultiReqBuffer *mrb)
block_acct_invalid(blk_get_stats(req->dev->blk),
is_write ? BLOCK_ACCT_WRITE : BLOCK_ACCT_READ);
virtio_blk_free_request(req);
- return;
+ return 0;
}
block_acct_start(blk_get_stats(req->dev->blk),
@@ -576,6 +578,7 @@ static void virtio_blk_handle_request(VirtIOBlockReq *req,
MultiReqBuffer *mrb)
virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
virtio_blk_free_request(req);
}
+ return 0;
}
void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
@@ -586,7 +589,11 @@ void virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
blk_io_plug(s->blk);
while ((req = virtio_blk_get_request(s, vq))) {
- virtio_blk_handle_request(req, &mrb);
+ if (virtio_blk_handle_request(req, &mrb)) {
+ virtqueue_detach_element(req->vq, &req->elem, 0);
+ virtio_blk_free_request(req);
+ break;
+ }
}
if (mrb.num_reqs) {
@@ -625,7 +632,18 @@ static void virtio_blk_dma_restart_bh(void *opaque)
while (req) {
VirtIOBlockReq *next = req->next;
- virtio_blk_handle_request(req, &mrb);
+ if (virtio_blk_handle_request(req, &mrb)) {
+ /* Device is now broken and won't do any processing until it gets
+ * reset. Already queued requests will be lost: let's purge them.
+ */
+ while (req) {
+ next = req->next;
+ virtqueue_detach_element(req->vq, &req->elem, 0);
+ virtio_blk_free_request(req);
+ req = next;
+ }
+ break;
+ }
req = next;
}
