[dpdk-dev] Question on documentation / Mellanox ConnectX-3

[Adrien Mazarguil]

On Tue, Apr 03, 2018 at 02:59:38PM -0300, Marcelo Ricardo Leitner wrote:
> Hi,
> 
> http://docs.openvswitch.org/en/latest/howto/dpdk/ says:
> 
> Some NICs (i.e. Mellanox ConnectX-3) have only one PCI address
> associated with multiple ports. Using a PCI device like above won’t
> work. Instead, below usage is suggested:
> 
> $ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
>     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:01"
> $ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
>     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55:02"
> 
> But these MACs are 7 bytes long. Seems the idea was to mention the two
> incremental MAC addresses that the ports have, and thus the ':55'
> should have been removed from there, right?
> 
> Reading the code, it doesn't seem prepared to handle the extra byte in
> any (special) way.

After a quick glance at the original patch [1], I confirm it looks like a
mistake in the OVS documentation. MAC addresses should be 6 bytes long, the
7th byte is not a workaround to identify a physical port like I initially
thought.

As you pointed out, since default MAC addresses on mlx4 ports are normally
incremental, documentation should read something like:

 $ ovs-vsctl add-port br0 dpdk-p0 -- set Interface dpdk-p0 type=dpdk \
     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:55"
 $ ovs-vsctl add-port br0 dpdk-p1 -- set Interface dpdk-p1 type=dpdk \
     options:dpdk-devargs="class=eth,mac=00:11:22:33:44:56"

[1] https://github.com/openvswitch/ovs/commit/5e7588186839

-- 
Adrien Mazarguil
6WIND