Serialized DPU and Host Boot Sequence

Following a server power cycle, both the DPU and Host OSes begin boot at the same moment. On some servers, Host OS may complete boot before DPU services are fully operational.

By using serialized DPU and Host boot as described below, the boot flow can be serialized between DPU and Host. On every server power cycle, DPU initiates its boot sequence while holding Host OS from booting during its BIOS execution phase, until DPU Arm-OS is up. Once DPU Arm-OS is up, Host OS is released to start loading.

Prerequisite

This feature relies on the use of UEFI with expansion ROM enabled (by default it is enabled). Please verify the following:

• If you are using a host with Arm CPU:

  • Make sure EXP_ROM_UEFI_ARM_ENABLE is set to True (1)

• If you are using a host with x86 CPU:

  • Make sure EXP_ROM_UEFI_x86_ENABLE is set to True (1)

Enabling and Disabling Serialized DPU and Host Boot

To Enable:

From host or Arm-OS console, run:

            

            
#> sudo mlxconfig -d /dev/mst/<device> s DELAY_HOST_OS_INIT=1
        

For this configuration to take effect, BlueField reset should be applied.

To Disable:

From host or Arm-OS console, run:

            

            
#> sudo mlxconfig -d /dev/mst/<device> s DELAY_HOST_OS_INIT=2
        

For this configuration to take effect, BlueField reset should be applied.