Re: [Intel-wired-lan] [PATCH iwl-next v7 09/12] iavf: refactor iavf_clean_rx_irq to support legacy and flex descriptors

[Simon Horman <horms@kernel.org>]

On Tue, Jun 04, 2024 at 09:13:57AM -0400, Mateusz Polchlopek wrote:
> From: Jacob Keller <jacob.e.keller@intel.com>
> 
> Using VIRTCHNL_VF_OFFLOAD_FLEX_DESC, the iAVF driver is capable of
> negotiating to enable the advanced flexible descriptor layout. Add the
> flexible NIC layout (RXDID=2) as a member of the Rx descriptor union.
> 
> Also add bit position definitions for the status and error indications
> that are needed.
> 
> The iavf_clean_rx_irq function needs to extract a few fields from the Rx
> descriptor, including the size, rx_ptype, and vlan_tag.
> Move the extraction to a separate function that decodes the fields into
> a structure. This will reduce the burden for handling multiple
> descriptor types by keeping the relevant extraction logic in one place.
> 
> To support handling an additional descriptor format with minimal code
> duplication, refactor Rx checksum handling so that the general logic
> is separated from the bit calculations. Introduce an iavf_rx_desc_decoded
> structure which holds the relevant bits decoded from the Rx descriptor.
> This will enable implementing flexible descriptor handling without
> duplicating the general logic twice.
> 
> Introduce an iavf_extract_flex_rx_fields, iavf_flex_rx_hash, and
> iavf_flex_rx_csum functions which operate on the flexible NIC descriptor
> format instead of the legacy 32 byte format. Based on the negotiated
> RXDID, select the correct function for processing the Rx descriptors.
> 
> With this change, the Rx hot path should be functional when using either
> the default legacy 32byte format or when we switch to the flexible NIC
> layout.
> 
> Modify the Rx hot path to add support for the flexible descriptor
> format and add request enabling Rx timestamps for all queues.
> 
> As in ice, make sure we bump the checksum level if the hardware detected
> a packet type which could have an outer checksum. This is important
> because hardware only verifies the inner checksum.
> 
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>
> Co-developed-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>
> Signed-off-by: Mateusz Polchlopek <mateusz.polchlopek@intel.com>

Reviewed-by: Simon Horman <horms@kernel.org>