Re: [dpdk-dev] [PATCH v4 1/2] common/mlx5: add provider query port support to glue library

[Raslan Darawsheh <rasland@nvidia.com>]

Hi,

> -----Original Message-----
> From: Slava Ovsiienko <viacheslavo@nvidia.com>
> Sent: Wednesday, July 7, 2021 6:54 PM
> To: dev@dpdk.org
> Cc: Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad
> <matan@nvidia.com>; NBU-Contact-Thomas Monjalon
> <thomas@monjalon.net>; david.marchand@redhat.com; stable@dpdk.org
> Subject: [PATCH v4 1/2] common/mlx5: add provider query port support to
> glue library
> 
> In order to get E-Switch vport identifiers the mlx5 PMD relies
> on two approaches:
>   [a] use port query API if it is provided by rdma-core library
>   [b] otherwise, deduce vport ids from the related VF index
> The latter is not reliable and may not work with newer kernel
> drivers and in some configurations (LAG), causing E-Switch
> malfunction. Hence, engaging the port query API is highly
> desirable.
> 
> Depending on rdma-core version the port query API is:
>   - very old OFED versions have no query API (approach [b])
>   - rdma-core OFED < 5.5 provides mlx5dv_query_devx_port,
>     HAVE_MLX5DV_DR_DEVX_PORT flag is defined (approach [a])
>   - rdma-core OFED >= 5.5 has mlx5dv_query_port, flag
>     HAVE_MLX5DV_DR_DEVX_PORT_V35 is defined (approach [a])
>   - future OFED versions might remove mlx5dv_query_devx_port
>     and HAVE_MLX5DV_DR_DEVX_PORT will not be defined
>   - Upstream rdma-core < v35 has no port query API (approach [b])
>   - Upstream rdma-core >= v35 has  mlx5dv_query_port, flag
>     HAVE_MLX5DV_DR_DEVX_PORT_V35 is defined (approach [a])
> 
> In order to support the new mlx5dv_query_port routine, the
> conditional compilation flag HAVE_MLX5DV_DR_DEVX_PORT_V35
> is introduced by the this patch. The flag HAVE_MLX5DV_DR_DEVX_PORT
> is kept for compatibility with previous rdma-core versions.
> 
> Despite this patch is not a bugfix (it follows the introduced API
> variation in underlying library), it resolves the compatibility
> issue and is highly desired to be ported to DPDK LTS.
> 
> Cc: stable@dpdk.org
> 
> Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>

Replaced older version and pushed to next-net-mlx,

Kindest regards,
Raslan Darawsheh