Subject: Re: [PATCH net-next 4/4] virtio-net: remove F_GUEST_CSUM check for XDP loading

From: "Michael S. Tsirkin" <[email-masked]>
Date: Mon, 19 Jun 2023 07:16:20 -0400

On Mon, Jun 19, 2023 at 06:57:38PM +0800, Heng Qi wrote:
> Lay the foundation for the subsequent patch

which subsequent patch? this is the last one in series.

> to complete the coexistence
> of XDP and virtio-net guest csum.
> 
> Signed-off-by: Heng Qi <[email-masked]>
> Reviewed-by: Xuan Zhuo <[email-masked]>
> ---
>  drivers/net/virtio_net.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 25b486ab74db..79471de64b56 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -60,7 +60,6 @@ static const unsigned long guest_offloads[] = {
>  	VIRTIO_NET_F_GUEST_TSO6,
>  	VIRTIO_NET_F_GUEST_ECN,
>  	VIRTIO_NET_F_GUEST_UFO,
> -	VIRTIO_NET_F_GUEST_CSUM,
>  	VIRTIO_NET_F_GUEST_USO4,
>  	VIRTIO_NET_F_GUEST_USO6,
>  	VIRTIO_NET_F_GUEST_HDRLEN

What is this doing? Drop support for VIRTIO_NET_F_GUEST_CSUM? Why?
This will disable all of guest offloads I think ..

> @@ -3522,10 +3521,9 @@ static int virtnet_xdp_set(struct net_device *dev, struct bpf_prog *prog,
>  	        virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_TSO6) ||
>  	        virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_ECN) ||
>  		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_UFO) ||
> -		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_CSUM) ||
>  		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO4) ||
>  		virtio_has_feature(vi->vdev, VIRTIO_NET_F_GUEST_USO6))) {
> -		NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing GRO_HW/CSUM, disable GRO_HW/CSUM first");
> +		NL_SET_ERR_MSG_MOD(extack, "Can't set XDP while host is implementing GRO_HW, disable GRO_HW first");
>  		return -EOPNOTSUPP;
>  	}
>  
> -- 
> 2.19.1.6.gb485710b