net/mlx5: fix the compatibility with MISC4

  When eCPRI offloading is introduced, the support for misc parameters
4 of flow table entry (FTE) match set is needed. The structure of
"mlx5_ifc_fte_match_param_bits" is extended with
"mlx5_ifc_fte_match_set_misc4_bits" at the end of it. The total size
of the FTE match set will be changed into 384 bytes from 320 bytes.
Low level user space driver (rdma-core) will have the validation of
the length of FTE match set. In the old release that no MISC4
supported in the rdma-core, the validation will fail, and this will
break the backward compatibility, even if the MISC4 is not used in
most cases.
In order to make new mlx5 PMD work well with old rdma-core, the
length adjustment needs to be done. When creating a flow, the lengths
of the matcher and value are both set to 320 without MISC4. There is
no need to change the structure definition, all bytes of the MISC4
will be discarded if it is not needed. Or else, like in eCPRI
matching, the lengths will be adjusted to 384 for matcher creation
and value matching.

Fixes: afa8556c873c ("net/mlx5: add flow translation of eCPRI header")

Signed-off-by: Bing Zhao <bingz@mellanox.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
 drivers/net/mlx5/mlx5_flow_dv.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)
  

Hi,

> -----Original Message-----
> From: Bing Zhao <bingz@mellanox.com>
> Sent: Monday, July 20, 2020 12:04 PM
> To: Ori Kam <orika@mellanox.com>; Slava Ovsiienko
> <viacheslavo@mellanox.com>
> Cc: Raslan Darawsheh <rasland@mellanox.com>; Matan Azrad
> <matan@mellanox.com>; dev@dpdk.org
> Subject: [PATCH] net/mlx5: fix the compatibility with MISC4
> 
> When eCPRI offloading is introduced, the support for misc parameters
> 4 of flow table entry (FTE) match set is needed. The structure of
> "mlx5_ifc_fte_match_param_bits" is extended with
> "mlx5_ifc_fte_match_set_misc4_bits" at the end of it. The total size
> of the FTE match set will be changed into 384 bytes from 320 bytes.
> Low level user space driver (rdma-core) will have the validation of
> the length of FTE match set. In the old release that no MISC4
> supported in the rdma-core, the validation will fail, and this will
> break the backward compatibility, even if the MISC4 is not used in
> most cases.
> In order to make new mlx5 PMD work well with old rdma-core, the
> length adjustment needs to be done. When creating a flow, the lengths
> of the matcher and value are both set to 320 without MISC4. There is
> no need to change the structure definition, all bytes of the MISC4
> will be discarded if it is not needed. Or else, like in eCPRI
> matching, the lengths will be adjusted to 384 for matcher creation
> and value matching.
> 
> Fixes: afa8556c873c ("net/mlx5: add flow translation of eCPRI header")
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow_dv.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow_dv.c
> b/drivers/net/mlx5/mlx5_flow_dv.c
> index ee66a44..778a766 100644
> --- a/drivers/net/mlx5/mlx5_flow_dv.c
> +++ b/drivers/net/mlx5/mlx5_flow_dv.c
> @@ -5765,7 +5765,15 @@ struct field_modify_info modify_tcp[] = {
>  	dev_flow = &((struct mlx5_flow *)priv->inter_flows)[priv-
> >flow_idx++];
>  	dev_flow->handle = dev_handle;
>  	dev_flow->handle_idx = handle_idx;
> -	dev_flow->dv.value.size = MLX5_ST_SZ_BYTES(fte_match_param);
> +	/*
> +	 * In some old rdma-core releases, before continuing, a check of the
> +	 * length of matching parameter will be done at first. It needs to use
> +	 * the length without misc4 param. If the flow has misc4 support,
> then
> +	 * the length needs to be adjusted accordingly. Each param member
> is
> +	 * aligned with a 64B boundary naturally.
> +	 */
> +	dev_flow->dv.value.size = MLX5_ST_SZ_BYTES(fte_match_param) -
> +				  MLX5_ST_SZ_BYTES(fte_match_set_misc4);
>  	/*
>  	 * The matching value needs to be cleared to 0 before using. In the
>  	 * past, it will be automatically cleared when using rte_*alloc
> @@ -7986,7 +7994,8 @@ struct field_modify_info modify_tcp[] = {
>  	uint64_t priority = attr->priority;
>  	struct mlx5_flow_dv_matcher matcher = {
>  		.mask = {
> -			.size = sizeof(matcher.mask.buf),
> +			.size = sizeof(matcher.mask.buf) -
> +				MLX5_ST_SZ_BYTES(fte_match_set_misc4),
>  		},
>  	};
>  	int actions_n = 0;
> @@ -8678,6 +8687,10 @@ struct field_modify_info modify_tcp[] = {
>  						NULL,
>  						"cannot create eCPRI
> parser");
>  			}
> +			/* Adjust the length matcher and device flow value.
> */
> +			matcher.mask.size =
> MLX5_ST_SZ_BYTES(fte_match_param);
> +			dev_flow->dv.value.size =
> +
> 	MLX5_ST_SZ_BYTES(fte_match_param);
>  			flow_dv_translate_item_ecpri(dev, match_mask,
>  						     match_value, items);
>  			/* No other protocol should follow eCPRI layer. */
> --
> 1.8.3.1

Patch squashed into relevant commit in master-net-mlx,

Kindest regards,
Raslan Darawsheh