Re: [PATCH v3 1/2] virtio_net: disable VIRTIO_NET_F_STANDBY if VIRTIO_NET_F_MAC is not set

[Michael S. Tsirkin]

On Fri, Jan 27, 2023 at 09:44:59PM +0100, Laurent Vivier wrote:
> failover relies on the MAC address to pair the primary and the standby
> devices:
> 
>   "[...] the hypervisor needs to enable VIRTIO_NET_F_STANDBY
>    feature on the virtio-net interface and assign the same MAC address
>    to both virtio-net and VF interfaces."
> 
>   Documentation/networking/net_failover.rst
> 
> This patch disables the STANDBY feature if the MAC address is not
> provided by the hypervisor.
> 
> Signed-off-by: Laurent Vivier <lvivier@xxxxxxxxxx>

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

> ---
>  drivers/net/virtio_net.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 7723b2a49d8e..7d700f8e545a 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3688,6 +3688,12 @@ static int virtnet_validate(struct virtio_device *vdev)
>  			__virtio_clear_bit(vdev, VIRTIO_NET_F_MTU);
>  	}
>  
> +	if (virtio_has_feature(vdev, VIRTIO_NET_F_STANDBY) &&
> +	    !virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
> +		dev_warn(&vdev->dev, "device advertises feature VIRTIO_NET_F_STANDBY but not VIRTIO_NET_F_MAC, disabling standby");
> +		__virtio_clear_bit(vdev, VIRTIO_NET_F_STANDBY);
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.39.1