Re: [PATCH 07/16] virtio-net: support queue reset

[Jason Wang]

在 2022/7/18 19:17, Kangjie Xu 写道:
> From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>
> virtio-net implements queue reset. Queued packets in the corresponding
> queue pair are flushed or purged.
>
> Queue reset is currently only implemented for non-vhosts.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>   hw/net/virtio-net.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 7ad948ee7c..8396e21a67 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -531,6 +531,19 @@ static RxFilterInfo 
> *virtio_net_query_rxfilter(NetClientState *nc)
>       return info;
>   }
>   
> +static void virtio_net_queue_reset(VirtIODevice *vdev, uint32_t queue_index)
> +{
> +    VirtIONet *n = VIRTIO_NET(vdev);
> +    NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(queue_index));
> +
> +    if (!nc->peer) {
> +        return;
> +    }
> +
> +    qemu_flush_or_purge_queued_packets(nc->peer, true);
> +    assert(!virtio_net_get_subqueue(nc)->async_tx.elem);


Let's try to reuse this function in virtio_net_reset().


> +}
> +
>   static void virtio_net_reset(VirtIODevice *vdev)
>   {
>       VirtIONet *n = VIRTIO_NET(vdev);
> @@ -741,6 +754,7 @@ static uint64_t virtio_net_get_features(VirtIODevice *vdev, 
> uint64_t features,
>       }
>   
>       if (!get_vhost_net(nc->peer)) {
> +        virtio_add_feature(&features, VIRTIO_F_RING_RESET);


This breaks migration compatibility.

We probably need:

1) a new command line parameter
2) make it disabled for pre-7.2 machine

Thanks


>           return features;
>       }
>   
> @@ -3766,6 +3780,7 @@ static void virtio_net_class_init(ObjectClass *klass, void *data)
>       vdc->set_features = virtio_net_set_features;
>       vdc->bad_features = virtio_net_bad_features;
>       vdc->reset = virtio_net_reset;
> +    vdc->queue_reset = virtio_net_queue_reset;
>       vdc->set_status = virtio_net_set_status;
>       vdc->guest_notifier_mask = virtio_net_guest_notifier_mask;
>       vdc->guest_notifier_pending = virtio_net_guest_notifier_pending;