On Wed, Oct 11, 2023 at 02:14:26PM +0800, lv.mengz...@zte.com.cn wrote: > From: hujian <hu.j...@zte.com.cn> > > During the stop of dataplane for virtio-blk, > virtio_bus_cleanup_host_notifier() is be > called to clean up notifier at the end, if polled ioeventfd, > virtio_blk_handle_output() > is used to handle io request. But due to s->dataplane_disabled is false, it > will be > returned directly, which drops io request. > Backtrace: > ->virtio_blk_data_plane_stop > ->virtio_bus_cleanup_host_notifier > ->virtio_queue_host_notifier_read > ->virtio_queue_notify_vq > ->vq->handle_output > ->virtio_blk_handle_output > ->if (s->dataplane && !s->dataplane_stoped) > ->if (!s->dataplane_disabled) > ->return * > ->virtio_blk_handle_output_do > The above problem can occur when using "virsh reset" cmdline to reset guest, > while > guest does io. > To fix this problem, don't try to start dataplane if s->stopping is true, and > io would > be handled by virtio_blk_handle_vq(). > > Signed-off-by: hujian <hu.j...@zte.com.cn> > --- > hw/block/virtio-blk.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-)
I have dropped this patch again after Fiona pointed out it does not
compile and Kevin noticed that handling requests from the main loop
thread while the I/O is still being processed in the IOThread is going
to cause thread-safety issues.
Can you explain the problem you are seeing in more detail? You run
"virsh reset" while the guest is doing I/O. Then what happens?
Stefan
>
> diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
> index 39e7f23..c2d5938 100644
> --- a/hw/block/virtio-blk.c
> +++ b/hw/block/virtio-blk.c
> @@ -1166,7 +1166,7 @@ static void virtio_blk_handle_output(VirtIODevice
> *vdev, VirtQueue *vq)
> {
> VirtIOBlock *s = (VirtIOBlock *)vdev;
>
> - if (s->dataplane && !s->dataplane_started) {
> + if (s->dataplane && !s->dataplane_started && !s->stopping) {
> /* Some guests kick before setting VIRTIO_CONFIG_S_DRIVER_OK so start
> * dataplane here instead of waiting for .set_status().
> */
> --
> 1.8.3.1
>
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