[dpdk-dev] [PATCH v6 0/9] ethdev: support SubFunction representor

[Stephen Hemminger]

On Sun, 14 Feb 2021 03:21:30 +0000
Xueming Li <xuemingl at nvidia.com> wrote:

> SubFunction [1] is a portion of the PCI device, a SF netdev has its own
> dedicated queues(txq, rxq). A SF netdev supports E-Switch representation
> offload similar to existing PF and VF representors. A SF shares PCI
> level resources with other SFs and/or with its parent PCI function.
> 
> From SmartNIC perspective, when PCI device is shared for multi-host,
> representors for host controller and host PF is required.
> 
> This patch set introduces new representor types in addtion to existing
> VF representor. Syntax:
> 
> [[c#]pf#]vf#: VF port representor/s from controller/pf
> [[c#]pf#]sf#: SF port representor/s from controller/pf
> #: VF representor - for backwards compatibility
> 
> "#" is number instance, list or range, valid examples:
>   1, [1,3,5], [0-3], [0,2-4,6]
> 
> For backward compatibility, this patch also introduces new netdev
> capability to indicate the capability of supportting SF representor.
> 
> Version history:
>  RFC:
>  	initial version [2]
>  V2:
>     - separate patch for represnetor infrastructure, controller, pf and
>       sf.
>     - replace representor ID macro with functions:
>       rte_eth_representor_id_encode()
>       rte_eth_representor_id_parse()
>     - new patch to allow devargs with same PCI BDF but different
>       representors.
>     - other minor code updates according to comments, thanks Andrew!
>     - update document
>  V3:
>     - improve probing of allowed devargs with same name.
>     - parse single word of kvargs as key.
>     - update kvargs test cases.
>  V4:
>     - split first representor refactor patch into
>       1: add representor type
>       2: refector representor list parsing
>     - push the patch supporting multi-devargs for same device.
>  V5:
>     - add comments for parsing functions
>     - update switch_representation.rst - Thanks Ajit
>  V6:
>     - split representor types into different patches, move to
>       rte_ethdev.h
>     - improvements of rte_eth_devargs_process_list() according to
>       Andrew's suggestion
>     - fixed PF probe failure for Intel i40e
>     - replace ethdev SF capability with rte_eth_representor_info_get()
>     - add new ethdev ops api to get representor info from PMD
>     - replace representor ID encode/decode with conversion from
>       representor info
>     - change ethdev representor iterator to use new ID encoding
> 
> 
> Xueming Li (9):
>   ethdev: introduce representor type
>   ethdev: support representor port list
>   ethdev: support new VF representor syntax
>   ethdev: support sub function representor
>   ethdev: support PF index in representor
>   ethdev: support multi-host in representor
>   ethdev: new API to get representor info
>   ethdev: representor iterator compare complete info
>   kvargs: update parser to support lists
> 
>  app/test/test_kvargs.c                        |  46 ++++-
>  config/rte_config.h                           |   1 +
>  doc/guides/prog_guide/poll_mode_drv.rst       |  13 +-
>  .../prog_guide/switch_representation.rst      |  35 +++-
>  drivers/net/bnxt/bnxt_ethdev.c                |   7 +
>  drivers/net/enic/enic_ethdev.c                |   6 +
>  drivers/net/i40e/i40e_ethdev.c                |   7 +
>  drivers/net/ixgbe/ixgbe_ethdev.c              |   7 +
>  drivers/net/mlx5/linux/mlx5_os.c              |  11 ++
>  lib/librte_ethdev/ethdev_driver.h             |  49 ++++-
>  lib/librte_ethdev/ethdev_private.c            | 173 ++++++++++++------
>  lib/librte_ethdev/ethdev_private.h            |   3 -
>  lib/librte_ethdev/rte_class_eth.c             |  40 ++--
>  lib/librte_ethdev/rte_ethdev.c                | 102 ++++++++++-
>  lib/librte_ethdev/rte_ethdev.h                |  53 ++++++
>  lib/librte_ethdev/version.map                 |   4 +
>  lib/librte_kvargs/rte_kvargs.c                | 101 +++++++---
>  17 files changed, 535 insertions(+), 123 deletions(-)
> 

A couple of higher level design questions:
1. How does Linux and other OS handle this in their API?
2. This solution seems quite tied into a specific implementation on your hardware.
   Is there a PCI standard for this?
3. Maybe a more general solution where these were represented as buses would
   allow for other connection methods in the future?