Re: [dpdk-dev] [dpdk-stable] [PATCH] net/mlx5: fix matcher metadata register c0 field setup

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 12/20/2019 7:48 AM, Viacheslav Ovsiienko wrote:
> The metadata register c0 field in the matcher might be split
> into two independent fields - the source vport index and META
> item value. These fields have no permanent assigned bits, the
> configuration is queried from the kernel drivers.
> 
> MLX5_SET configures the specified 32-bit field as whole entity.
> For metadata register c0 we should take into account the provided
> mask in order to configure the specified subfield bits only.

Hi Slava,

Is there a more human friendly name for the field instead of "C0"?

I don't know what "matcher metadata register" is, what is the impact of the fix?
Which functionality was broken now fixed? Does it make sense to reflect it in
the patch title / commit log?

Same comment for the related patches:
net/mlx5: fix register c0 usage for metadata entities
net/mlx5: fix metadata item endianness conversion

> 
> Fixes: acfcd5c52f94 ("net/mlx5: update meta register matcher set")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow_dv.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c b/drivers/net/mlx5/mlx5_flow_dv.c
> index 4c16281..893db3e 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -5742,6 +5742,7 @@ struct field_modify_info modify_tcp[] = {
>  		MLX5_ADDR_OF(fte_match_param, matcher, misc_parameters_2);
>  	void *misc2_v =
>  		MLX5_ADDR_OF(fte_match_param, key, misc_parameters_2);
> +	uint32_t temp;
>  
>  	data &= mask;
>  	switch (reg_type) {
> @@ -5754,8 +5755,18 @@ struct field_modify_info modify_tcp[] = {
>  		MLX5_SET(fte_match_set_misc2, misc2_v, metadata_reg_b, data);
>  		break;
>  	case REG_C_0:
> -		MLX5_SET(fte_match_set_misc2, misc2_m, metadata_reg_c_0, mask);
> -		MLX5_SET(fte_match_set_misc2, misc2_v, metadata_reg_c_0, data);
> +		/*
> +		 * The metadata register C0 field might be divided into
> +		 * source vport index and META item value, we should set
> +		 * this field accorfing to specified mask, not as whole one.
> +		 */
> +		temp = MLX5_GET(fte_match_set_misc2, misc2_m, metadata_reg_c_0);
> +		temp |= mask;
> +		MLX5_SET(fte_match_set_misc2, misc2_m, metadata_reg_c_0, temp);
> +		temp = MLX5_GET(fte_match_set_misc2, misc2_v, metadata_reg_c_0);
> +		temp &= ~mask;
> +		temp |= data;
> +		MLX5_SET(fte_match_set_misc2, misc2_v, metadata_reg_c_0, temp);
>  		break;
>  	case REG_C_1:
>  		MLX5_SET(fte_match_set_misc2, misc2_m, metadata_reg_c_1, mask);
>