On Tue, Feb 13, 2018 at 09:53:58PM +0100, Peter Lieven wrote: > > Am 21.12.2017 um 15:29 schrieb Michael S. Tsirkin: > > Backends don't need to know what frontend requested a reset, > > and notifying then from virtio_error is messy because > > virtio_error itself might be invoked from backend. > > > > Let's just set the status directly. > > > > Cc: qemu-sta...@nongnu.org > > Reported-by: Ilya Maximets <i.maxim...@samsung.com> > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > > --- > > hw/virtio/virtio.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > > index ad564b0..d6002ee 100644 > > --- a/hw/virtio/virtio.c > > +++ b/hw/virtio/virtio.c > > @@ -2469,7 +2469,7 @@ void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice > > *vdev, const char *fmt, ...) > > va_end(ap); > > > > if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { > > - virtio_set_status(vdev, vdev->status | > > VIRTIO_CONFIG_S_NEEDS_RESET); > > + vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET; > > virtio_notify_config(vdev); > > } > > > > > Is it possible that this patch introduces a stall in I/O and a deadlock on a > drain all? > > I have seen Qemu VMs being I/O stalled and deadlocking on a vm stop command in > > blk_drain_all. This happened after a longer storage outage. > > > I am asking just theoretically because I have seen this behaviour first when > we > > backported this patch in our stable 2.9 branch. > > > Thank you, > > Peter
Well - this patch was introduced to fix a crash, but a well behaved VM should not trigger VIRTIO_CONFIG_S_NEEDS_RESET - did you see any error messages in the log when this triggered? -- MST