Re: [dpdk-dev] [PATCH] vdpa/mlx5: fix the compatibility with MISC4

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 7/21/20 10:13 AM, Bing Zhao wrote:
> When dynamic flex parser feature 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, and this will break the backward
> compatibility, even if the MISC4 is not used in most cases, like
> in vDPA driver.
> In order not to break the compatibility old rdma-core, the length
> adjustment needs to be done. In mlx5 vDPA driver, 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. Since the MISC4 parameter
> is aligned with a 64B boundary and so does the whole FTE match set
> parameter, there is no need to take any padding and alignment into
> consideration when calculating the size.
> 
> Fixes: 32132fb8517c ("net/mlx5: add flow translation of eCPRI header")
> 
> Signed-off-by: Bing Zhao <bingz@mellanox.com>
> Acked-by: Matan Azrad <matan@mellanox.com>
> ---
>  drivers/vdpa/mlx5/mlx5_vdpa_steer.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Please note the sha-1 in the fixes tag was not good, I fixed it.

Applied to dpdk-next-virtio/master

Thanks,
Maxime