Re: [dpdk-dev] [PATCH v4 1/5] ethdev: negotiate delivery of packet metadata from HW to PMD

[Ori Kam <orika@nvidia.com>]

Hi Ivan,

Just a nit below.

> -----Original Message-----
> From: Ivan Malov <ivan.malov@oktetlabs.ru>
> Sent: Tuesday, October 5, 2021 2:50 AM
> Subject: [PATCH v4 1/5] ethdev: negotiate delivery of packet metadata from
> HW to PMD
> 
> Provide an API to let the application control the NIC's ability to deliver specific
> kinds of per-packet metadata to the PMD.
> 
> Checks for the NIC's ability to set these kinds of metadata in the first place
> (support for the flow actions) belong in flow API responsibility domain (flow
> validate mechanism).
> This topic is out of scope of the new API in question.
> 
> The PMD's ability to deliver received metadata to the user by virtue of mbuf
> fields should be covered by mbuf library.
> It is also out of scope of the new API in question.
> 

+1 very clear.

> Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
> Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
> Reviewed-by: Andy Moreton <amoreton@xilinx.com>
> Acked-by: Ray Kinsella <mdr@ashroe.eu>
> Acked-by: Jerin Jacob <jerinj@marvell.com>
> ---

[Snip]

> --- a/lib/ethdev/rte_ethdev.h
> +++ b/lib/ethdev/rte_ethdev.h
> @@ -4902,6 +4902,59 @@ __rte_experimental  int
> rte_eth_representor_info_get(uint16_t port_id,
>  				 struct rte_eth_representor_info *info);
> 
> +/** The NIC is able to deliver flag (if set) with packets to the PMD.
> +*/ #define RTE_ETH_RX_METADATA_USER_FLAG (UINT64_C(1) << 0)
> +
> +/** The NIC is able to deliver mark ID with packets to the PMD. */
> +#define RTE_ETH_RX_METADATA_USER_MARK (UINT64_C(1) << 1)
> +
> +/** The NIC is able to deliver tunnel ID with packets to the PMD. */
> +#define RTE_ETH_RX_METADATA_TUNNEL_ID (UINT64_C(1) << 2)
> +
> +/**
> + * @warning
> + * @b EXPERIMENTAL: this API may change without prior notice
> + *
> + * Negotiate the NIC's ability to deliver specific kinds of metadata to the PMD.
> + *
> + * Invoke this API before the first rte_eth_dev_configure() invocation
> + * to let the PMD make preparations that are inconvenient to do later.
> + *
> + * The negotiation process is as follows:
> + *
> + * - the application requests features intending to use at least some
> +of them;
> + * - the PMD responds with the guaranteed subset of the requested
> +feature set;
> + * - the application can retry negotiation with another set of
> +features;
> + * - the application can pass zero to clear the negotiation result;
> + * - the last negotiated result takes effect upon the ethdev start.

Not upon ethdev configure?

> + *
> + * @note
> + *   The PMD is supposed to first consider enabling the requested feature set
> + *   in its entirety. Only if it fails to do so, does it have the right to
> + *   respond with a smaller set of the originally requested features.
> + *
> + * @note
> + *   Return code (-ENOTSUP) does not necessarily mean that the requested
> + *   features are unsupported. In this case, the application should just
> + *   assume that these features can be used without prior negotiations.
> + *
> + * @param port_id
> + *   Port (ethdev) identifier
> + *
> + * @param[inout] features
> + *   Feature selection buffer
> + *
> + * @return
> + *   - (-EBUSY) if the port can't handle this in its current state;
> + *   - (-ENOTSUP) if the method itself is not supported by the PMD;
> + *   - (-ENODEV) if *port_id* is invalid;
> + *   - (-EINVAL) if *features* is NULL;
> + *   - (-EIO) if the device is removed;
> + *   - (0) on success
> + */
> +__rte_experimental
> +int rte_eth_rx_metadata_negotiate(uint16_t port_id, uint64_t
> +*features);
> +
>  #include <rte_ethdev_core.h>
> 
>  /**
> diff --git a/lib/ethdev/rte_flow.h b/lib/ethdev/rte_flow.h index
> 7b1ed7f110..75656ff9f8 100644
> --- a/lib/ethdev/rte_flow.h
> +++ b/lib/ethdev/rte_flow.h
> @@ -1904,6 +1904,10 @@ enum rte_flow_action_type {
>  	 * PKT_RX_FDIR_ID mbuf flags.
>  	 *
>  	 * See struct rte_flow_action_mark.
> +	 *
> +	 * One should negotiate mark delivery from the NIC to the PMD.
> +	 * @see rte_eth_rx_metadata_negotiate()
> +	 * @see RTE_ETH_RX_METADATA_USER_MARK
>  	 */
>  	RTE_FLOW_ACTION_TYPE_MARK,
> 
> @@ -1912,6 +1916,10 @@ enum rte_flow_action_type {
>  	 * sets the PKT_RX_FDIR mbuf flag.
>  	 *
>  	 * No associated configuration structure.
> +	 *
> +	 * One should negotiate flag delivery from the NIC to the PMD.
> +	 * @see rte_eth_rx_metadata_negotiate()
> +	 * @see RTE_ETH_RX_METADATA_USER_FLAG
>  	 */
>  	RTE_FLOW_ACTION_TYPE_FLAG,
> 
> @@ -4223,6 +4231,10 @@ rte_flow_tunnel_match(uint16_t port_id,
>  /**
>   * Populate the current packet processing state, if exists, for the given mbuf.
>   *
> + * One should negotiate tunnel metadata delivery from the NIC to the HW.
> + * @see rte_eth_rx_metadata_negotiate()
> + * @see RTE_ETH_RX_METADATA_TUNNEL_ID
> + *
>   * @param port_id
>   *   Port identifier of Ethernet device.
>   * @param[in] m
> diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map index
> 904bce6ea1..2e638c680e 100644
> --- a/lib/ethdev/version.map
> +++ b/lib/ethdev/version.map
> @@ -247,6 +247,9 @@ EXPERIMENTAL {
>  	rte_mtr_meter_policy_delete;
>  	rte_mtr_meter_policy_update;
>  	rte_mtr_meter_policy_validate;
> +
> +	# added in 21.11
> +	rte_eth_rx_metadata_negotiate;
>  };
> 
>  INTERNAL {
> --
> 2.20.1
Best,
Ori