On Sun, 29 Jan 2023 02:25:43 -0500, "Michael S. Tsirkin" <m...@redhat.com>
wrote:
> On Sun, Jan 29, 2023 at 10:51:50AM +0800, Xuan Zhuo wrote:
> > Check whether it is per-queue reset state in virtio_net_flush_tx().
> >
> > Before per-queue reset, we need to recover async tx resources. At this
> > time, virtio_net_flush_tx() is called, but we should not try to send
> > new packets, so virtio_net_flush_tx() should check the current
> > per-queue reset state.
>
>
> What does "at this time" mean here?
> Do you in fact mean it's called from flush_or_purge_queued_packets?
Yes
virtio_queue_reset
k->queue_reset
virtio_net_queue_reset
flush_or_purge_queued_packets
qemu_flush_or_purge_queued_packets
.....
(callback) virtio_net_tx_complete
virtio_net_flush_tx <-- here
send new packet. We need stop it.
Because it is inside the callback, I can't pass information through the stack. I
originally thought it was a general situation, so I wanted to put it in
struct VirtQueue.
If it is not very suitable, it may be better to put it in VirtIONetQueue.
Thanks.
> What does the call stack look like?
>
> If yes introducing a vq state just so virtio_net_flush_tx
> knows we are in the process of reset would be a bad idea.
> We want something much more local, ideally on stack even ...
>
>
> >
> > Fixes: 7dc6be52 ("virtio-net: support queue reset")
> > Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1451
> > Reported-by: Alexander Bulekov <alx...@bu.edu>
> > Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
> > ---
> > hw/net/virtio-net.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> > index 3ae909041a..fba6451a50 100644
> > --- a/hw/net/virtio-net.c
> > +++ b/hw/net/virtio-net.c
> > @@ -2627,7 +2627,8 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q)
> > VirtQueueElement *elem;
> > int32_t num_packets = 0;
> > int queue_index = vq2q(virtio_get_queue_index(q->tx_vq));
> > - if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK)) {
> > + if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) ||
> > + virtio_queue_reset_state(q->tx_vq)) {
> > return num_packets;
> > }
> >
> > --
> > 2.32.0.3.g01195cf9f
>
