[ovs-dev] [PATCHv2] docs: Add header install command for afxdp.

William Tu u9012063 at gmail.com
Thu Jan 23 17:03:11 UTC 2020

The 'XDP_RING_NEED_WAKEUP' and related flags are defined if_xdp.h, so if
users are building their own kernel, users have to update the kernel's
header files, by doing:

  $ make headers_install INSTALL_HDR_PATH=/usr

Otherwise the following error shows:
/usr/local/include/bpf/xsk.h: In function 'xsk_ring_prod__needs_wakeup':
/usr/local/include/bpf/xsk.h:82:21: error: 'XDP_RING_NEED_WAKEUP' undeclared \
  (first use in this function)
  return *r->flags & XDP_RING_NEED_WAKEUP;

Reported-by: Tomek Osinski <osinstom at gmail.com>
Reported-at: https://osinstom.github.io/en/tutorial/ovs-afxdp-installation/
Signed-off-by: William Tu <u9012063 at gmail.com>
Acked-by: Ben Pfaff <blp at ovn.org>
 Documentation/intro/install/afxdp.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/intro/install/afxdp.rst b/Documentation/intro/install/afxdp.rst
index c4685fa7ebac..99003e4dbdb2 100644
--- a/Documentation/intro/install/afxdp.rst
+++ b/Documentation/intro/install/afxdp.rst
@@ -108,6 +108,14 @@ vSwitch with AF_XDP will require the following:
   * CONFIG_XDP_SOCKETS_DIAG=y (Debugging)
+- If you're building your own kernel, be sure that you're installing kernel
+  headers too.  For example, with the following command::
+    make headers_install INSTALL_HDR_PATH=/usr
+- If you're using kernel from the distribution, be sure that corresponding
+  kernel headers package installed.
 - Once your AF_XDP-enabled kernel is ready, if possible, run
   **./xdpsock -r -N -z -i <your device>** under linux/samples/bpf.
   This is an OVS independent benchmark tools for AF_XDP.

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