X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Faf_xdp.rst;h=5ed24374f8a67959adff2014e3c4facca3b597f9;hb=6ada10deac667cd2f79bd08d25dd068c04747fe5;hp=be268fe7ff28210ea537a540560fdc1ed5b69851;hpb=288a85aef192df4bafc2a5720cfa0b94ab543b3c;p=dpdk.git

diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index be268fe7ff..5ed24374f8 100644
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -50,6 +50,7 @@ This is a Linux-specific PMD, thus the following prerequisites apply:
 *  For PMD zero copy, it requires kernel version later than v5.4-rc1;
 *  For shared_umem, it requires kernel version v5.10 or later and libbpf version
    v0.2.0 or later.
+*  For 32-bit OS, a kernel with version 5.4 or later is required.
 
 Set up an af_xdp interface
 -----------------------------
@@ -82,3 +83,28 @@ Limitations
 
   Note: The AF_XDP PMD will fail to initialise if an MTU which violates the driver's
   conditions as above is set prior to launching the application.
+
+- **Shared UMEM**
+
+  The sharing of UMEM is only supported for AF_XDP sockets with unique contexts.
+  The context refers to the netdev,qid tuple.
+
+  The following combination will fail:
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f1,shared_umem=1 \
+
+  Either of the following however is permitted since either the netdev or qid differs
+  between the two vdevs:
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f1,start_queue=1,shared_umem=1 \
+
+  .. code-block:: console
+
+    --vdev net_af_xdp0,iface=ens786f1,shared_umem=1 \
+    --vdev net_af_xdp1,iface=ens786f2,shared_umem=1 \
\ No newline at end of file