Configuring Uplink MTU
To configure the port MTU while operating in DPU mode, users must restrict the external host port ownership by issuing the following command on the BlueField:
mlxprivhost -d /dev/mst/<pciconf0 device> r --disable_port_owner
Server cold reboot is required for this restriction to take effect.
Once the host is restricted, the port MTU is configured by changing the MTU of the uplink representor (p0 or p1).
To return the DPU to its default state and restore port ownership to the host, you must revert the host restriction to Privileged mode.
Run the following command on the BlueField DPU:
mlxprivhost -d /dev/mst/<pciconf0 device> p
The configuration takes effect immediately.
You must revert this configuration (restore the host to Privileged mode) before switching the BlueField DPU to NIC mode. Failure to do so may prevent the host from properly detecting or managing the network interfaces in NIC mode.