[v2,bpf,0/5] New netdev feature flags for XDP

From: Marek Majtyka <marekx.majtyka@intel.com>

Implement support for checking if a netdev has native XDP and AF_XDP zero
copy support. Previously, there was no way to do this other than to try
to create an AF_XDP socket on the interface or load an XDP program and
see if it worked. This commit changes this by extending existing
netdev_features in the following way:
 * xdp        - full XDP support (XDP_{TX, PASS, DROP, ABORT, REDIRECT})
 * af-xdp-zc  - AF_XDP zero copy support
NICs supporting these features are updated by turning the corresponding
netdev feature flags on.

NOTE:
 Only the compilation check was performed for:
  - ice, 
  - igb,
  - mlx5, 
  - mlx4.
  - bnxt, 
  - dpaa2, 
  - mvmeta, 
  - mvpp2, 
  - qede,
  - sfc, 
  - netsec, 
  - cpsw, 
  - xen, 
  - netronome
  - ena
  - virtio_net.

Libbpf library is extended in order to provide a simple API for gathering
information about XDP supported capabilities of a netdev. This API
utilizes netlink interface towards kernel. With this function it is
possible to get xsk supported options for netdev beforehand.
The new API is used in core xsk code as well as in the xdpsock sample.

These new flags also solve the problem with strict recognition of zero
copy support. The problem is that there are drivers out there that only
support XDP partially, so it is possible to successfully load the XDP
program in native mode, but it will still not be able to support zero-copy
as it does not have XDP_REDIRECT support. With af-xdp-zc flag the check
is possible and trivial.

Changes since v1:
 * Replace netdev_feature flags variable with a bitmap of XDP-specific
   properties. New kernel and uapi interfaces are added to handle access
   to the XDP netdev properties bitmap. [Toke]

 * Set more fine grained XPD properties for netdevs when necessary. [Toke]

 * Extend ethtool netlink interface in order to get access to the XDP
   bitmap (XDP_PROPERTIES_GET). [Toke]

 * Removed the libbpf patches for now.
---
Marek Majtyka (5):
  net: ethtool: add xdp properties flag set
  drivers/net: turn XDP properties on
  xsk: add usage of xdp properties flags
  xsk: add check for full support of XDP in bind
  ethtool: provide xdp info with XDP_PROPERTIES_GET

 .../networking/netdev-xdp-properties.rst      | 42 ++++++++
 drivers/net/ethernet/amazon/ena/ena_netdev.c  |  2 +
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |  1 +
 .../net/ethernet/freescale/dpaa2/dpaa2-eth.c  |  1 +
 drivers/net/ethernet/intel/i40e/i40e_main.c   |  3 +
 drivers/net/ethernet/intel/ice/ice_main.c     |  4 +
 drivers/net/ethernet/intel/igb/igb_main.c     |  2 +
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  3 +
 drivers/net/ethernet/marvell/mvneta.c         |  3 +
 .../net/ethernet/marvell/mvpp2/mvpp2_main.c   |  3 +
 .../net/ethernet/mellanox/mlx4/en_netdev.c    |  2 +
 .../net/ethernet/mellanox/mlx5/core/en_main.c |  3 +
 .../ethernet/netronome/nfp/nfp_net_common.c   |  5 +
 drivers/net/ethernet/qlogic/qede/qede_main.c  |  2 +
 drivers/net/ethernet/sfc/efx.c                |  2 +
 drivers/net/ethernet/socionext/netsec.c       |  2 +
 drivers/net/ethernet/ti/cpsw.c                |  3 +
 drivers/net/ethernet/ti/cpsw_new.c            |  2 +
 drivers/net/tun.c                             |  4 +
 drivers/net/veth.c                            |  2 +
 drivers/net/virtio_net.c                      |  2 +
 drivers/net/xen-netfront.c                    |  2 +
 include/linux/netdevice.h                     |  2 +
 include/linux/xdp_properties.h                | 53 +++++++++++
 include/net/xdp.h                             | 95 +++++++++++++++++++
 include/net/xdp_sock_drv.h                    | 10 ++
 include/uapi/linux/ethtool.h                  |  1 +
 include/uapi/linux/ethtool_netlink.h          | 14 +++
 include/uapi/linux/if_xdp.h                   |  1 +
 include/uapi/linux/xdp_properties.h           | 32 +++++++
 net/ethtool/Makefile                          |  2 +-
 net/ethtool/common.c                          | 11 +++
 net/ethtool/common.h                          |  4 +
 net/ethtool/netlink.c                         | 38 +++++---
 net/ethtool/netlink.h                         |  2 +
 net/ethtool/strset.c                          |  5 +
 net/ethtool/xdp.c                             | 76 +++++++++++++++
 net/xdp/xsk.c                                 |  4 +-
 net/xdp/xsk_buff_pool.c                       | 20 +++-
 tools/include/uapi/linux/if_xdp.h             |  1 +
 tools/lib/bpf/xsk.c                           |  3 +
 41 files changed, 449 insertions(+), 20 deletions(-)
 create mode 100644 Documentation/networking/netdev-xdp-properties.rst
 create mode 100644 include/linux/xdp_properties.h
 create mode 100644 include/uapi/linux/xdp_properties.h
 create mode 100644 net/ethtool/xdp.c


base-commit: eceae70bdeaeb6b8ceb662983cf663ff352fbc96

On Fri,  4 Dec 2020 11:28:56 +0100 alardam@gmail.com wrote:
>  * Extend ethtool netlink interface in order to get access to the XDP
>    bitmap (XDP_PROPERTIES_GET). [Toke]

That's a good direction, but I don't see why XDP caps belong in ethtool
at all? We use rtnetlink to manage the progs...

Jakub Kicinski <kuba@kernel.org> writes:

> On Fri, 04 Dec 2020 18:26:10 +0100 Toke Høiland-Jørgensen wrote:

>> Jakub Kicinski <kuba@kernel.org> writes:

>> 

>> > On Fri,  4 Dec 2020 11:28:56 +0100 alardam@gmail.com wrote:  

>> >>  * Extend ethtool netlink interface in order to get access to the XDP

>> >>    bitmap (XDP_PROPERTIES_GET). [Toke]  

>> >

>> > That's a good direction, but I don't see why XDP caps belong in ethtool

>> > at all? We use rtnetlink to manage the progs...  

>> 

>> You normally use ethtool to get all the other features a device support,

>> don't you?

>

> Not really, please take a look at all the IFLA attributes. There's 

> a bunch of capabilities there.


Ah, right, TIL. Well, putting this new property in rtnetlink instead of
ethtool is fine by me as well :)

-Toke