docs: Add note for AF_XDP installation

Add notes about some configuration issues when enabling AF_XDP
support.

Signed-off-by: Yi-Hung Wei <yihung.wei@gmail.com>
Signed-off-by: William Tu <u9012063@gmail.com>

diff --git a/Documentation/intro/install/afxdp.rst b/Documentation/intro/install/afxdp.rst
index 99003e4dbdb22bb38305c44b53dd721af8850269..3c8f78825b418a310e905213111bc5b2ba99cc99 100644 (file)
--- a/Documentation/intro/install/afxdp.rst
+++ b/Documentation/intro/install/afxdp.rst
@@ -146,11 +146,20 @@ Make sure the libbpf.so is installed correctly::
   ldconfig
   ldconfig -p | grep libbpf
 
+.. note::
+   Check /etc/ld.so.conf if libbpf is installed but can not be found by
+   ldconfig.
+
 Third, ensure the standard OVS requirements are installed and
 bootstrap/configure the package::
 
   ./boot.sh && ./configure --enable-afxdp
 
+.. note::
+   If you encounter "WARNING: bpf/libbpf.h: present but cannot be compiled",
+   check the Linux headers are in line with libbpf. For example, in Ubuntu,
+   check the installed linux-headers* and linux-libc-dev* dpkg.
+
 Finally, build and install OVS::
 
   make && make install