Re: [PATCH] vdpa/mlx5: Use random MAC address when no nic vport MAC set

[Jason Wang]

On Wed, Aug 28, 2024 at 12:03 AM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
> When the vdpa device is configured without a specific MAC
> address, the vport MAC address is used. However, this
> address can be 0 which prevents the driver from properly
> configuring the MPFS and breaks steering.
>
> The solution is to simply generate a random MAC address
> when no MAC is set on the nic vport.
>
> Now it's possible to create a vdpa device without a
> MAC address and run qemu with this device without needing
> to configure an explicit MAC address.
>
> Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>

Acked-by: Jason Wang <jasowang@xxxxxxxxxx>

(Adding Cindy for double checking if it has any side effect on Qemu side)

Thanks

> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index fa78e8288ebb..1c26139d02fe 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -3824,6 +3824,9 @@ static int mlx5_vdpa_dev_add(struct vdpa_mgmt_dev *v_mdev, const char *name,
>                 err = mlx5_query_nic_vport_mac_address(mdev, 0, 0, config->mac);
>                 if (err)
>                         goto err_alloc;
> +
> +               if (is_zero_ether_addr(config->mac))
> +                       eth_random_addr(config->mac);
>         }
>
>         if (!is_zero_ether_addr(config->mac)) {
> --
> 2.45.1
>