RE: [PATCH 1/2] net/mlx5: fix egress group translation in HWS

[Suanming Mou <suanmingm@nvidia.com>]

> -----Original Message-----
> From: Dariusz Sosnowski <dsosnowski@nvidia.com>
> Sent: Sunday, February 26, 2023 4:18 AM
> To: Matan Azrad <matan@nvidia.com>; Slava Ovsiienko
> <viacheslavo@nvidia.com>
> Cc: dev@dpdk.org; stable@dpdk.org; Ori Kam <orika@nvidia.com>
> Subject: [PATCH 1/2] net/mlx5: fix egress group translation in HWS
> 
> With HW Steering enabled creating egress template tables and egress flow rules
> on E-Switch setups is allowed.
> To enable it, PMD creates a set of default egress flow rules responsible for:
> 
> - Storing representor ID (vport tag is used) in HW register.
>   This is used for traffic source identification.
> - Copying software metadata to proper HW register to allow
>   preserving metadata across domains.
> 
> Structure of these flow rules and whether they are inserted depend on the
> device configuration.
> There are the following cases:
> 
> 1. repr_matching=1 and dv_xmeta_en=4
>    - An egress flow rule in group 0 is created for each Tx queue;
>    - Flow rule matching SQ number - fills unused REG_C_0 bits
>      with vport tag, copies REG_A to REG_C_1 and jumps to group 1.
> 2. repr_matching=1 and dv_xmeta_en=0
>    - An egress flow rule in group 0 is created for each Tx queue;
>    - Flow rule matching SQ number - fills unused REG_C_0 bits
>      with vport tag and jumps to group 1.
> 3. repr_matching=0 and dv_xmeta_en=4
>    - A single egress flow rule in group 0 is created;
>    - Flow rule matches all E-Switch manager TX traffic,
>      copies REG_A to REG_C and jumps to group 1.
> 4. repr_matching=0 and dv_xmeta_en=0 - no default flow rules are added.
> 
> When default egress flow rules are required, they are inserted in group 0 and
> this group is reserved for PMD purposes.
> User created template tables must be created in higher groups.
> As a result, on template table creation PMD is translating the provided group
> (incrementing it in that case).
> 
> Before this patch, a condition used to check if translation of egress flow group is
> needed was incorrect. It did not allow translation if both representor matching
> AND extended metadata mode were enabled.
> 
> This patch fixes this condition - translation is allowed if and only if representor
> matching OR extended metadata mode is enabled.
> 
> Fixes: 483181f7b6dd ("net/mlx5: support device control of representor
> matching")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Dariusz Sosnowski <dsosnowski@nvidia.com>
> Acked-by: Ori Kam <orika@nvidia.com>
Acked-by: Suanming Mou <suanmingm@nvidia.com>