Re: [PATCH 1/4] vdpa/mlx5: Fix rule forwarding VLAN to TIR

[Si-Wei Liu]

Hi Eli,

It's not for this patch but something related, so just a friendly 
heads-up. I haven't validated the VLAN tagging behavior yet for mlx5 
vdpa, but from my quick read of the code it doesn't seem it 
differentiates the case with and without VIRTIO_NET_F_CTRL_VLAN, to be 
compatible/compliant with what's been implemented in QEMU software (a 
spec addendum was filed as requested by Michael):

https://github.com/oasis-tcs/virtio-spec/issues/147

- when VIRTIO_NET_F_CTRL_VLAN is negotiated, the device starts with
all VLANs filtered (meaning only untagged traffic can be received,
and traffic with VLAN tag will be dropped).

- when VIRTIO_NET_F_CTRL_VLAN is not negotiated, all traffic including
untagged and tagged can be received.

Can you please help check if we need further fix in terms of VLAN tagging?

Thanks,
-Siwei


On 10/18/2022 4:12 AM, Eli Cohen wrote:
> Set the VLAN id to the header values field instead of overwriting the
> headers criteria field.
>
> Before this fix, VLAN filtering would not really work and tagged packets
> would be forwarded unfiltered to the TIR.
>
> Fixes: baf2ad3f6a98 ("vdpa/mlx5: Add RX MAC VLAN filter support")
>
> Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
Reviewed-by: Si-Wei Liu <si-wei.liu@xxxxxxxxxx>

> ---
>   drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 90913365def4..dd29fdfc24ed 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1472,7 +1472,7 @@ static int mlx5_vdpa_add_mac_vlan_rules(struct mlx5_vdpa_net *ndev, u8 *mac,
>   	if (tagged) {
>   		MLX5_SET(fte_match_set_lyr_2_4, headers_v, cvlan_tag, 1);
>   		MLX5_SET_TO_ONES(fte_match_set_lyr_2_4, headers_c, first_vid);
> -		MLX5_SET(fte_match_set_lyr_2_4, headers_c, first_vid, vid);
> +		MLX5_SET(fte_match_set_lyr_2_4, headers_v, first_vid, vid);
>   	}
>   	flow_act.action = MLX5_FLOW_CONTEXT_ACTION_FWD_DEST;
>   	dest.type = MLX5_FLOW_DESTINATION_TYPE_TIR;