docs: Clarify creation & bonding of DPDK enabled interfaces.

Unlike system interfaces, DPDK enabled interfaces must have their interface
type explicitly set when used to create ports.  Mention this in relevant parts
of the documentation and add references to INTALL.DPDK.md, where there are many
examples.

Signed-off-by: Billy O'Mahony <[email protected]>
Signed-off-by: Ben Pfaff <[email protected]>

FAQ.md

@@ -360,6 +360,25 @@ A: Yes.  How you configure it depends on what you mean by "promiscuous
     SPAN, see "How do I configure a port as a SPAN port, that is,
     enable mirroring of all traffic to that port?"
 
+### Q: How do I configure a DPDK port as an access port?
+
+A: Firstly, you must have a DPDK-enabled version of Open vSwitch.
+
+   If your version is DPDK-enabled it will support the --dpdk
+   argument on the command line and will display lines with
+   "EAL:..." during startup when --dpdk is supplied.
+
+   Secondly, when adding a DPDK port, unlike a system port, the
+   type for the interface must be specified. For example;
+
+       ovs-vsctl add-br br0
+       ovs-vsctl add-port br0 dpdk0 -- set Interface dpdk0 type=dpdk
+
+   Finally, it is required that DPDK port names begin with 'dpdk'.
+
+   See [INSTALL.DPDK.md] for more information on enabling and using DPDK with
+   Open vSwitch.
+
 ### Q: How do I configure a VLAN as an RSPAN VLAN, that is, enable mirroring of all traffic to that VLAN?
 
 A: The following commands configure br0 with eth0 as a trunk port and
@@ -649,6 +668,9 @@ A: More than likely, you've looped your network.  Probably, eth0 and
      documentation on the Port table in ovs-vswitchd.conf.db(5)
      for all the details.
 
+     Configuration for DPDK-enabled interfaces is slightly less
+     straightforward: see [INSTALL.DPDK.md].
+
    - Perhaps you don't actually need eth0 and eth1 to be on the
      same bridge.  For example, if you simply want to be able to
      connect each of them to virtual machines, then you can put
@@ -1897,3 +1919,4 @@ http://openvswitch.org/
 [WHY-OVS.md]:WHY-OVS.md
 [INSTALL.md]:INSTALL.md
 [OPENFLOW-1.1+.md]:OPENFLOW-1.1+.md
+[INSTALL.DPDK.md]:INSTALL.DPDK.md

INSTALL.DPDK.md

@@ -187,6 +187,14 @@ Using the DPDK with ovs-vswitchd:
    polls dpdk device in continuous loop. Therefore CPU utilization
    for that thread is always 100%.
 
+   Note: creating bonds of DPDK interfaces is slightly different to creating
+   bonds of system interfaces.  For DPDK, the interface type must be explicitly
+   set, for example:
+
+   ```
+   ovs-vsctl add-bond br0 dpdkbond dpdk0 dpdk1 -- set Interface dpdk0 type=dpdk -- set Interface dpdk1 type=dpdk
+   ```
+
 7. Add test flows
 
    Test flow script across NICs (assuming ovs in /usr/src/ovs):

utilities/ovs-vsctl.8.in

@@ -282,7 +282,9 @@ is an error.  With \fB\-\-may\-exist\fR, this command does nothing if
 .IP "[\fB\-\-fake\-iface\fR] \fBadd\-bond \fIbridge port iface\fR\&... [\fIcolumn\fR[\fB:\fIkey\fR]\fR=\fIvalue\fR]\&...\fR"
 Creates on \fIbridge\fR a new port named \fIport\fR that bonds
 together the network devices given as each \fIiface\fR.  At least two
-interfaces must be named.
+interfaces must be named.  If the interfaces are DPDK enabled then
+the transaction will need to include operations to explicitly set the
+interface type to 'dpdk'.
 .IP
 Optional arguments set values of column in the Port record created by
 the command.  The syntax is the same as that for the \fBset\fR command