Re: [PATCH v2 6/7] vdpa/mlx5: conditionally show MTU and STATUS in config space

[Eli Cohen <elic@nvidia.com>]

On 01/02/2023 1:22, Si-Wei Liu wrote:
> The spec says:
>      mtu only exists if VIRTIO_NET_F_MTU is set
>      status only exists if VIRTIO_NET_F_STATUS is set
>
> We should only show MTU and STATUS conditionally depending on
> the feature bits.
>
> Signed-off-by: Si-Wei Liu <si-wei.liu@oracle.com>
> ---
>   drivers/vdpa/mlx5/net/mlx5_vnet.c | 22 ++++++++++++++--------
>   1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 3a6dbbc6..3d49eae 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -3009,6 +3009,8 @@ static int event_handler(struct notifier_block *nb, unsigned long event, void *p
>   	struct mlx5_vdpa_wq_ent *wqent;
>   
>   	if (event == MLX5_EVENT_TYPE_PORT_CHANGE) {
> +		if (!(ndev->mvdev.actual_features & BIT_ULL(VIRTIO_NET_F_STATUS)))
> +			return NOTIFY_DONE;
>   		switch (eqe->sub_type) {
>   		case MLX5_PORT_CHANGE_SUBTYPE_DOWN:
>   		case MLX5_PORT_CHANGE_SUBTYPE_ACTIVE:
> @@ -3118,16 +3120,20 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
>   			goto err_alloc;
>   	}
>   
> -	err = query_mtu(mdev, &mtu);
> -	if (err)
> -		goto err_alloc;
> +	if (device_features & BIT_ULL(VIRTIO_NET_F_MTU)) {
> +		err = query_mtu(mdev, &mtu);
> +		if (err)
> +			goto err_alloc;
device_features is not defined as a local variable. It is defined in the 
next patch.
>   
> -	ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu);
> +		ndev->config.mtu = cpu_to_mlx5vdpa16(mvdev, mtu);
> +	}
>   
> -	if (get_link_state(mvdev))
> -		ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
> -	else
> -		ndev->config.status &= cpu_to_mlx5vdpa16(mvdev, ~VIRTIO_NET_S_LINK_UP);
> +	if (device_features & BIT_ULL(VIRTIO_NET_F_STATUS)) {
> +		if (get_link_state(mvdev))
> +			ndev->config.status |= cpu_to_mlx5vdpa16(mvdev, VIRTIO_NET_S_LINK_UP);
> +		else
> +			ndev->config.status &= cpu_to_mlx5vdpa16(mvdev, ~VIRTIO_NET_S_LINK_UP);
> +	}
>   
>   	if (add_config->mask & (1 << VDPA_ATTR_DEV_NET_CFG_MACADDR)) {
>   		memcpy(ndev->config.mac, add_config->net.mac, ETH_ALEN);