Date:   Tue, 31 Jan 2023 17:09:30 -0500
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Laurent Vivier <lvivier@redhat.com>
Cc:     linux-kernel@vger.kernel.org,
        "David S. Miller" <davem@davemloft.net>,
        virtualization@lists.linux-foundation.org,
        Cindy Lu <lulu@redhat.com>, Eli Cohen <elic@nvidia.com>,
        Gautam Dawar <gautam.dawar@xilinx.com>,
        Eugenio =?iso-8859-1?Q?P=E9rez?= <eperezma@redhat.com>,
        Jason Wang <jasowang@redhat.com>, netdev@vger.kernel.org,
        Parav Pandit <parav@nvidia.com>
Subject: Re: [PATCH v3 1/2] virtio_net: disable VIRTIO_NET_F_STANDBY if
 VIRTIO_NET_F_MAC is not set
Message-ID: <20230131170923-mutt-send-email-mst@kernel.org>
References: <20230127204500.51930-1-lvivier@redhat.com>
 <20230127204500.51930-2-lvivier@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230127204500.51930-2-lvivier@redhat.com>
Precedence: bulk

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@redhat.com>

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

> ---
>  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