Re: [PATCH] virtio-net: not enable vq reset feature unconditionally

[Xuan Zhuo <xuanzhuo@linux.alibaba.com>]

On Thu,  4 May 2023 12:14:47 +0200, =?utf-8?q?Eugenio_P=C3=A9rez?= <eperezma@redhat.com> wrote:
> The commit 93a97dc5200a ("virtio-net: enable vq reset feature") enables
> unconditionally vq reset feature as long as the device is emulated.
> This makes impossible to actually disable the feature, and it causes
> migration problems from qemu version previous than 7.2.
>
> The entire final commit is unneeded as device system already enable or
> disable the feature properly.
>
> This reverts commit 93a97dc5200a95e63b99cb625f20b7ae802ba413.
> Fixes: 93a97dc5200a ("virtio-net: enable vq reset feature")
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
>
> ---
> Tested by checking feature bit at  /sys/devices/pci.../virtio0/features
> enabling and disabling queue_reset virtio-net feature and vhost=on/off
> on net device backend.

Do you mean that this feature cannot be closed?

I tried to close in the guest, it was successful.

In addition, in this case, could you try to repair the problem instead of
directly revert.

Thanks.

> ---
>  hw/net/virtio-net.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 53e1c32643..4ea33b6e2e 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -805,7 +805,6 @@ 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);
>          return features;
>      }
>
> --
> 2.31.1
>