Re: [dpdk-dev] [PATCH] net/mlx5: fix actions validation on root table

[Raslan Darawsheh <rasland@mellanox.com>]

Hi,

> -----Original Message-----
> From: Bing Zhao <bingz@mellanox.com>
> Sent: Wednesday, April 29, 2020 3:54 PM
> To: Slava Ovsiienko <viacheslavo@mellanox.com>; Raslan Darawsheh
> <rasland@mellanox.com>
> Cc: Ori Kam <orika@mellanox.com>; Matan Azrad <matan@mellanox.com>;
> dev@dpdk.org; stable@dpdk.org
> Subject: [PATCH] net/mlx5: fix actions validation on root table
> 
> The maximal supported header modifications number of a single modify
> context on the root table cannot be queried from firmware directly.
> It is a fixed value of 16 in the latest releases. In the validation
> stage, PMD driver should ensure that no more than 16 header modify
> actions exist in a single context.
> In some old firmware releases, the supported value is 8. PMD driver
> should try its best to create the flow. Firmware will return error
> and refuse to create the flow if the actions number exceeds the
> maximal value.
> 
> Fixes: 72a944dba163 ("net/mlx5: fix header modify action validation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow.h    | 12 +++++++-----
>  drivers/net/mlx5/mlx5_flow_dv.c | 17 +++++++----------
>  2 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.h b/drivers/net/mlx5/mlx5_flow.h
> index 2a1f596..75b8288 100644
> --- a/drivers/net/mlx5/mlx5_flow.h
> +++ b/drivers/net/mlx5/mlx5_flow.h
> @@ -415,14 +415,16 @@ struct mlx5_flow_dv_tag_resource {
> 
>  /*
>   * Number of modification commands.
> - * If extensive metadata registers are supported, the maximal actions
> amount is
> - * 16 and 8 otherwise on root table. The validation could also be done in the
> - * lower driver layer.
> - * On non-root table, there is no limitation, but 32 is enough right now.
> + * The maximal actions amount in FW is some constant, and it is 16 in the
> + * latest releases. In some old releases, it will be limited to 8.
> + * Since there is no interface to query the capacity, the maximal value
> should
> + * be used to allow PMD to create the flow. The validation will be done in
> the
> + * lower driver layer or FW. A failure will be returned if exceeds the maximal
> + * supported actions number on the root table.
> + * On non-root tables, there is no limitation, but 32 is enough right now.
>   */
>  #define MLX5_MAX_MODIFY_NUM			32
>  #define MLX5_ROOT_TBL_MODIFY_NUM		16
> -#define MLX5_ROOT_TBL_MODIFY_NUM_NO_MREG	8
> 
>  /* Modify resource structure */
>  struct mlx5_flow_dv_modify_hdr_resource {
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c
> b/drivers/net/mlx5/mlx5_flow_dv.c
> index 6263ecc..ba2febf 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -3640,21 +3640,18 @@ struct field_modify_info modify_tcp[] = {
>   * @return
>   *   Max number of modify header actions device can support.
>   */
> -static unsigned int
> -flow_dv_modify_hdr_action_max(struct rte_eth_dev *dev, uint64_t flags)
> +static inline unsigned int
> +flow_dv_modify_hdr_action_max(struct rte_eth_dev *dev __rte_unused,
> +			      uint64_t flags)
>  {
>  	/*
> -	 * There's no way to directly query the max cap. Although it has to be
> -	 * acquried by iterative trial, it is a safe assumption that more
> -	 * actions are supported by FW if extensive metadata register is
> -	 * supported. (Only in the root table)
> +	 * There's no way to directly query the max capacity from FW.
> +	 * The maximal value on root table should be assumed to be
> supported.
>  	 */
>  	if (!(flags & MLX5DV_DR_ACTION_FLAGS_ROOT_LEVEL))
>  		return MLX5_MAX_MODIFY_NUM;
>  	else
> -		return mlx5_flow_ext_mreg_supported(dev) ?
> -					MLX5_ROOT_TBL_MODIFY_NUM :
> -
> 	MLX5_ROOT_TBL_MODIFY_NUM_NO_MREG;
> +		return MLX5_ROOT_TBL_MODIFY_NUM;
>  }
> 
>  /**
> @@ -5347,7 +5344,7 @@ struct field_modify_info modify_tcp[] = {
>  	    dev_conf->dv_xmeta_en != MLX5_XMETA_MODE_LEGACY &&
>  	    mlx5_flow_ext_mreg_supported(dev))
>  		rw_act_num += MLX5_ACT_NUM_SET_TAG;
> -	if ((uint32_t)rw_act_num >=
> +	if ((uint32_t)rw_act_num >
>  			flow_dv_modify_hdr_action_max(dev, is_root)) {
>  		return rte_flow_error_set(error, ENOTSUP,
>  					  RTE_FLOW_ERROR_TYPE_ACTION,
> --
> 1.8.3.1

Patch applied on next-net-mlx,

Kindest regards,
Raslan Darawsheh