Subject: Re: [PATCH mlx5-next] RDMA/mlx5: Enable multiplane mode only when it is supported

From: Michal Swiatkowski <[email-masked]>
Date: Thu, 19 Dec 2024 14:23:04 +0100

On Thu, Dec 19, 2024 at 02:23:36PM +0200, Leon Romanovsky wrote:
> From: Mark Zhang <[email-masked]>
> 
> Driver queries vport_cxt.num_plane and enables multiplane when it is
> greater then 0, but some old FWs (versions from x.40.1000 till x.42.1000),
> report vport_cxt.num_plane = 1 unexpectedly.
> 
> Fix it by querying num_plane only when HCA_CAP2.multiplane bit is set.
> 
> Fixes: 2a5db20fa532 ("RDMA/mlx5: Add support to multi-plane device and port")
> Cc: [email-masked]
> Reported-by: Francesco Poli <[email-masked]>
> Closes: https://lore.kernel.org/all/nvs4i2v7o6vn6zhmtq4sgazy2hu5kiulukxcntdelggmznnl7h@so3oul6uwgbl/
> Signed-off-by: Mark Zhang <[email-masked]>
> Signed-off-by: Leon Romanovsky <[email-masked]>
> ---
>  drivers/infiniband/hw/mlx5/main.c | 2 +-
>  include/linux/mlx5/mlx5_ifc.h     | 4 +++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
> index c2314797afc9..f5b59d02f4d3 100644
> --- a/drivers/infiniband/hw/mlx5/main.c
> +++ b/drivers/infiniband/hw/mlx5/main.c
> @@ -2839,7 +2839,7 @@ static int mlx5_ib_get_plane_num(struct mlx5_core_dev *mdev, u8 *num_plane)
>  	int err;
>  
>  	*num_plane = 0;
> -	if (!MLX5_CAP_GEN(mdev, ib_virt))
> +	if (!MLX5_CAP_GEN(mdev, ib_virt) || !MLX5_CAP_GEN_2(mdev, multiplane))
>  		return 0;
>  
>  	err = mlx5_query_hca_vport_context(mdev, 0, 1, 0, &vport_ctx);
> diff --git a/include/linux/mlx5/mlx5_ifc.h b/include/linux/mlx5/mlx5_ifc.h
> index 4fbbcf35498b..48d47181c7cd 100644
> --- a/include/linux/mlx5/mlx5_ifc.h
> +++ b/include/linux/mlx5/mlx5_ifc.h
> @@ -2119,7 +2119,9 @@ struct mlx5_ifc_cmd_hca_cap_2_bits {
>  	u8	   migration_in_chunks[0x1];
>  	u8	   reserved_at_d1[0x1];
>  	u8	   sf_eq_usage[0x1];
> -	u8	   reserved_at_d3[0xd];
> +	u8	   reserved_at_d3[0x5];
> +	u8	   multiplane[0x1];
> +	u8	   reserved_at_d9[0x7];
>  
>  	u8	   cross_vhca_object_to_object_supported[0x20];

Reviewed-by: Michal Swiatkowski <[email-masked]>

Just out of curiosity, don't you have mlx5-net or sth like that for
fixes?

> -- 
> 2.47.0