[PATCH v10 0/1] Introduce AF_XDP PMD

[Xiaolong Ye <xiaolong.ye@intel.com>]

Overview
========

This patchset adds a new PMD driver for AF_XDP which is a proposed
faster version of AF_PACKET interface in Linux, see below links [1] [2] for
details of AF_XDP introduction:

AF_XDP roadmap
==============
- AF_XDP is included in upstream kernel since 4.18, and AF_XDP support
  in libbpf has been merged in v5.1-rc1.
- Now i40e and ixgbe drivers have supported zero copy mode.

Change logs
===========
v10:

- refine the Makefile, remove RTE_KERNELDIR related CFLAGS 
- add a new internal file af_xdp_deps.h to handle the dependency for
  asm/barrier.h
- fix a typo observed by Stephen
- rename xsk.h to bpf/xsk.h as xsk.h is assumed to be installed in
  /usr/local/include/bpf
- add libbpf build steps in af_xdp.rst


v9:
- adjust header files order according to Stephen's suggestion

v8:
- address Ferruh's comments on V7
- replace posix_memalign with rte_memzone_reserve_aligned to get better
  performance
- keep the first patch only as Oliver suggested as zero copy part
  implementation is still in suspense, we may provide the related patch
  later.

v7:
- mention mtu limitation in af_xdp.rst
- fix the vdev name in af_xdp.rst

V6:

- remove the newline in AF_XDP_LOG definition to avoid double new lines
  issue.
- rename MEMPOOL_F_PAGE_ALIGN to MEMPOOL_CHUNK_F_PAGE_ALIGN.

V5:

- disable AF_XDP pmd by default due to it requires kernel more recent
  than minimum kernel version supported by DPDK
- address other review comments of Maxime

V4:

- change vdev name to net_af_xdp
- adopt dynamic log type for all logging
- Fix other style issues raised by Stephen

V3:

- Fix all style issues pointed by Stephen, Mattias, David.
- Drop the testpmd change as we'll adopt Jerin's suggestion to add a new
  mempool driver to handle the application use of AF_XDP's zero copy feature.

V2:
- Fix a NULL pointer reference crash issue
- Fix txonly stop sending traffic in zc mode
- Refactor rte_mbuf.c to avoid ABI breakage.
- Fix multiple style issues pointed by Ferruh, David, Stephen, Luca.

changes vs RFC sent by Qi last Aug:

- Re-work base on AF_XDP's interface changes since the new libbpf has
  provided higher-level APIs that hide many of the details of the AP_XDP
  uapi. After the rework, it helps to reduce 300+ lines of code.

- multi-queues is not supported due to current libbpf doesn't support
  multi-sockets on a single umem.

- No extra steps to load xdp program manually, since the current behavior of
  libbpf would load a default xdp program when user calls xsk_socket__create.
  userspace application only needs to handle the cleanup.

How to try
==========

1. take the kernel >= v5.1-rc1, build kernel and replace your host
   kernel with it.
   
   make sure you turn on XDP sockets when compiling

   Networking support -->
        Networking options -->
                [ * ] XDP sockets
   
2. build & install libbpf in tools/lib/bpf

   cd tools/lib/bpf
   make install_lib
   make install_headers

3. ethtool -L enp59s0f0 combined 1

4. extra step to build dpdk

   explicitly enable AF_XDP pmd by adding below line to
   config/common_linux

   CONFIG_RTE_LIBRTE_PMD_AF_XDP=y

5. start testpmd

   ./build/app/testpmd -c 0xc -n 4 --vdev net_af_xdp,iface=enp59s0f0,queue=0 -- -i --rxq=1 --txq=1

    in this case, default xdp program will be loaded and linked to queue 0 of enp59s0f0,
    network traffics travel to queue 0 will be redirected to af_xdp socket.

Xiaolong Ye (1):
  net/af_xdp: introduce AF XDP PMD driver

 MAINTAINERS                                   |   7 +
 config/common_base                            |   5 +
 doc/guides/nics/af_xdp.rst                    |  50 +
 doc/guides/nics/features/af_xdp.ini           |  11 +
 doc/guides/nics/index.rst                     |   1 +
 doc/guides/rel_notes/release_19_05.rst        |   7 +
 drivers/net/Makefile                          |   1 +
 drivers/net/af_xdp/Makefile                   |  28 +
 drivers/net/af_xdp/af_xdp_deps.h              |  14 +
 drivers/net/af_xdp/meson.build                |  21 +
 drivers/net/af_xdp/rte_eth_af_xdp.c           | 955 ++++++++++++++++++
 drivers/net/af_xdp/rte_pmd_af_xdp_version.map |   3 +
 drivers/net/meson.build                       |   1 +
 mk/rte.app.mk                                 |   1 +
 14 files changed, 1105 insertions(+)
 create mode 100644 doc/guides/nics/af_xdp.rst
 create mode 100644 doc/guides/nics/features/af_xdp.ini
 create mode 100644 drivers/net/af_xdp/Makefile
 create mode 100644 drivers/net/af_xdp/af_xdp_deps.h
 create mode 100644 drivers/net/af_xdp/meson.build
 create mode 100644 drivers/net/af_xdp/rte_eth_af_xdp.c
 create mode 100644 drivers/net/af_xdp/rte_pmd_af_xdp_version.map

-- 
2.17.1