Re: [dpdk-dev] [RFC 1/3] ethdev: add item/action for SFT

[Ori Kam <orika@nvidia.com>]

Hi Andrey,

PSB

> -----Original Message-----
> From: Andrey Vesnovaty <andreyv@nvidia.com>
> Sent: Wednesday, September 9, 2020 11:30 PM
> 
> Attach SFT flow context to packet with SFT action.
> Match on SFT flow context (attached to packet),
> with SFT item.
> 
> Signed-off-by: Andrey Vesnovaty <andreyv@nvidia.com>
> ---
>  lib/librte_ethdev/rte_flow.h | 84 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 84 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> index da8bfa5489..24390e6ab4 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -537,6 +537,12 @@ enum rte_flow_item_type {
>  	 */
>  	RTE_FLOW_ITEM_TYPE_ECPRI,
> 
> +	/**
You are missing the Meta, tag not relevant for RFC but please notice for the patch.

> +	 * Matches SFT context (see fields of struct rte_flow_item_sft).
> +	 *
> +	 * See struct rte_flow_item_sft.
> +	 */
> +	RTE_FLOW_ITEM_TYPE_SFT,
>  };
> 
>  /**
> @@ -1579,6 +1585,54 @@ static const struct rte_flow_item_ecpri
> rte_flow_item_ecpri_mask = {
>  };
>  #endif
> 
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this structure may change without prior notice
> + *
> + * RTE_FLOW_ITEM_TYPE_SFT
> + *
> + * Matches context of flow in SFT table.
> + *
> + * 5-tuple: src/dest IP + src/dest port + IP protocol.
> + * zone: application defined value cupled with 5-tuple to identify flow,
> + * example - VxLAN, VLAN.
> + * SFT: Statfull flow table
> + * SFT in scope of ethernet device (port) is HW offloaded lookup table
> + * where key is zone + 5-tuple & value is statefull flow context.
> + * Contents of the SFT maintained by SFT PMD (see SFT PMD API in rte_sft).
> + *
> + * The structure describes SFT flow context.
> + * All the fields of the structure, except @p fid, should be considered as
> + * user defined.
> + * The @p fid assigned by RTE SFT & used as unique flow identifier.
> + * SFT context attached to packet by action ``SFT`` (see
> RTE_FLOW_ACTION_SFT).
> + *
> + * SFT default context defined as context attached to packet when there is no
> + * entry for the flow in SFT. The @p state has application reserved value
> + * meaning that SFT context for the packet undefined since entry wasn't found
> + * in SFT. If state 'undefined' then @p zone should be valid othervice @p fid
> + * should be valid.
> + *
> + * Context considered virtual since the method of storing this info on packet
> + * is PMD/implementation specific & may involve mapping methods if there is
> + * 'not enough bits' to store entire contents of struct rte_flow_item_sft.
> + *
> + * Maximal value/size of each field depends on HW capabilities and
> considered
> + * as implementation specific.
> + */
> +struct rte_flow_item_sft {
> +	union {
> +		uint32_t fid; /**< SFT flow identifier. */
> +		uint32_t zone; /**< Zone assigned to flow. */
> +	};
> +	uint8_t state; /**< User defined flow state. */
> +	uint8_t fid_valid:1; /**< fid field validity bit. */
> +	uint8_t zone_valid:1; /**< zone fieald validity bit. */
> +	uint8_t state_valid:1; /**< state fieald validity bit. */
> +	uint8_t user_data_size; /**< user_data buffer size. */
> +	uint8_t *user_data; /**< Arbitrary user data. */
> +};
> +
This object is only used to match and not set so
why do we need the union? I understand that later when reporting to the SFT in the application layer
sometimes you will get zone while other time you will get fid.
From rte flow you are matching on given object which is 32 bit.
What are the matchable  fields? (fid / zone / user_data / fid_valid ... )
Do you think that some of the times the match will be on he fid other on the zone?
If so they should not be union.
I think zone is the responsibility of the application to save and to match. So I don't see why it is
needed here.

>  /**
>   * Matching pattern item definition.
>   *
> @@ -2132,6 +2186,15 @@ enum rte_flow_action_type {
>  	 * see enum RTE_ETH_EVENT_FLOW_AGED
>  	 */
>  	RTE_FLOW_ACTION_TYPE_AGE,
> +
> +	/**
> +	 * RTE_FLOW_ACTION_TYPE_SFT
> +	 *
> +	 * Set SFT context and redirect to continue processing.
> +	 *
> +	 * See struct rte_flow_action_sft.
> +	 */
> +	RTE_FLOW_ACTION_TYPE_SFT,
>  };
> 
>  /**
> @@ -2721,6 +2784,27 @@ rte_flow_dynf_metadata_set(struct rte_mbuf *m,
> uint32_t v)
>  	*RTE_FLOW_DYNF_METADATA(m) = v;
>  }
> 
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this structure may change without prior notice
> + *
> + * RTE_FLOW_ACTION_TYPE_SFT
> + *
> + * Attaches an SFT context (see struct rte_flow_item_sft) to packet.
> + *
> + * Performs lookup by *zone* and 5-tuple in SFT; if entry found the related SFT
> + * context will be attached othervise default SFT context attached (see
> + * 'SFT default context' in struct rte_flow_item_sft description).
> + * Adding action of type ``SFT`` to the list of rule actions may impose
> + * limitations on other rule actions added to the list, depending on specific
> + * PMD implementation.
> + *
> + * For 5-tuple, zone & SFT definitions see `struct rte_flow_item_sft`.
> + */
> +struct rte_flow_action_sft {
> +	uint32_t zone; /**< Zone for lookup in SFT */
> +};
> +
>  /*
>   * Definition of a single action.
>   *
> --
> 2.26.2

Thanks,
Ori