Intelligent Platform Management Interface

IPMB requests can be initiated in 2 directions:

BlueField BMC-to-BlueField
BlueField-to-BlueField BMC

The NVIDIA® BlueField® networking platform's (DPU or SuperNIC) ipmb_dev_int driver is registered at the 7-bit I²C address 0x30 by default. The I²C address of the BlueField can be changed in the file /usr/bin/set_emu_param.sh.

BlueField Controller cards provide connection from the host server BMC to BlueField Arm I²C bus
BlueField devices provide connection from the host server BMC to the BlueField NC-SI port
BlueField Reference Platforms provide connection from its on-board BMC to BlueField Arm I²C bus

BlueField BMC IPMI Commands

The BlueField BMC is able to retrieve data from BlueField software over its Intelligent Platform Management Bus (IPMB).

For more details, please refer to the following sections of the NVIDIA BlueField BMC Software user manual under BMC SW tab.

Appendix - Generic IPMI Commands
Appendix - NVIDIA OEM IPMI Commands

BlueField IPMI Commands

The BlueField is able to retrieve data from the BlueField BMC over IPMB.

Issue a command with the following format from the BlueField to retrieve information from the BMC:

$ ipmitool <ipmitool command>

The BlueField may request information about itself using the following command format:

$ ipmitool -U ADMIN -P ADMIN -p 9001 -H localhost <ipmitool command>

The ipmb_host driver allows the BlueField to send requests to the BMC. Once set_emu_param.service is started, it will try to load the ipmb_host drivers. If the BMC is down or not responsive when BlueField tries to load the ipmb_host driver, the latter will not load successfully. In that case, make sure the BMC is up and operational, and run the following from BlueField's console:

echo 0x1011 > /sys/bus/i2c/devices/i2c-2/delete_device
rmmod ipmb_host

The set_emu_param.service script will try to load the driver again.

I²C Addresses for BMC-initiated Requests

Device	I²C Address
BlueField `ipmb_dev_int`	0x30
BMC `ipmb_host`	0x20

I²C Addresses for BlueField-initiated Requests

Device	I²C Address
BlueField `ipmb_host`	0x11
BMC `ipmb_dev_int`	0x10

Changing I²C Addresses

To use a different BlueField or BMC I²C address, you must make changes to the following files' variables.

Filename Path	Parameter Change
`/usr/bin/set_emu_param.sh`	The `ipmb_dev_int` and `ipmb_host` drivers are registered at the following I²C addresses: `IPMB_DEV_INT_ADD=<BlueField I`²`C Address 1>` `IPMB_HOST_ADD=<BlueField I`²`C Address 2>` These addresses must be different from one another. Otherwise, one of the drives will fail to register. To change the BMC I²C address: `IPMB_HOST_CLIENTADDR=<BMC I2C Address> <I2C Address> must be equal to: 0x1000+<7-bit I2C address>`

Filename Path

Parameter Change

/usr/bin/set_emu_param.sh

The ipmb_dev_int and ipmb_host drivers are registered at the following I²C addresses:

IPMB_DEV_INT_ADD=<BlueField I²C Address 1>
IPMB_HOST_ADD=<BlueField I²C Address 2>

These addresses must be different from one another. Otherwise, one of the drives will fail to register.

To change the BMC I²C address:

IPMB_HOST_CLIENTADDR=<BMC I2C Address>
<I2C Address> must be equal to: 0x1000+<7-bit I2C address>

Disabling IPMI from BlueField Arm to BMC

The BlueField SoC features two I2C channels connecting BlueField Arm and the BMC:

I2C-1 sends IPMI commands from BlueField Arm to the BMC
I2C-5 sends IPMI commands from the BMC to BlueField Arm

In cases where the BlueField Arm is not trusted, it may be desirable to block IPMI commands from the BlueField Arm to the BMC as it could grant a malicious actor root-level access to the BMC. This can be done via Redfish or the UEFI menu.

Disabling IPMI Using Redfish

Disable I2C-1:

curl -k -u root:'bmc_password' -H 'content-type: application/json' -d '{ "Attributes": { "DisableI2c1": true } }' -X PATCH https://<bmc_ip>/redfish/v1/Systems/Bluefield/Bios/Settings

Make sure the configuration is saved in the BMC's data base:

# curl -k -u root:'bmc_password' -H 'content-type: application/json' X GET https://<bmc_ip>/redfish/v1/Systems/Bluefield/Bios/Settings{
  "@odata.id": "/redfish/v1/Systems/Bluefield/Bios/Settings",
  "@odata.type": "#Bios.v1_2_0.Bios",
  "Attributes": {
    "DisableI2c1": true
  },
  "Description": "BIOS Settings",
  "Id": "BIOS_Settings",
  "Name": "BIOS Configuration"
}

Perform warm reset (e.g., SW_RESET) and wait for Redfish to run.
Perform warm reset (e.g., SW_RESET) and wait for Linux to boot.
Verify that i2c-1 has successfully been disabled:
```
root@localhost:~# ls /sys/bus/i2c/devices/
```
Expected output:
```
i2c-5
```
i2c-1 device should not appear.

Disabling IPMI Using UEFI Menu

Select Device Manager:
Select System Configuration:
Select Disable I2C1 (make sure it is marked with an X):
Press ESC key and type Y to save your changes.
Perform a warm reset (e.g., SW_RESET or via the reset option in the main menu of the UEFI menu) and wait for Linux to boot.
Verify that i2c-1 has successfully been disabled:
```
root@localhost:~# ls /sys/bus/i2c/devices/
```
Expected output:
```
i2c-5
```
i2c-1 device should not appear.

External Host IPMI Commands

It is possible for the external host to retrieve data from the BlueField via the IPMI LAN interface (either OOB or ConnectX).

To do that:

Set the network interface address properly in progconf. For example, if the OOB IP address is 192.168.101.2, edit the OOB_IP variable in the /etc/ipmi/progconf file as follows:
```
root@localhost:~# cat /etc/ipmi/progconf
SUPPORT_IPMB="NONE"
LOOP_PERIOD=3
BF_FAMILY=$(/usr/bin/bffamily | tr -d '[:space:]')
OOB_IP="192.168.101.2"
```
Then reboot or restart the IPMI service as follows:
```
systemctl restart mlx_ipmid
```
To get information from the BlueField, issue commands from the external host in the following format:
```
ipmitool -I lanplus -H 192.168.101.2 -U ADMIN -P ADMIN <ipmitool command>
```

Loading and Using IPMI on BlueField Running CentOS

Load the BlueField CentOS image:
The following steps are performed from the BlueField CentOS prompt. The BlueField is running CentOS 7.6 with kernel 5.4. The CentOS installation was done using the CentOS everything ISO image.

The following drivers need to be loaded on the BlueField running CentOS:
- jc42.ko
- ee1004.ko
- at24.ko
- eeprom.ko
- i2c-dev.ko
Example of loading ee1004.ko, at24.ko, and eeprom.ko:
```
modprobe ee1004
modprobe at24
modprobe eeprom
```
The i2c-dev module is built into the kernel 5.4.60 on CentOS 7.6.

(Optional) Update the i2c-mlx driver if the installed version is older than i2c-mlx-1.0-0.gab579c6.src.rpm.

Re-compile i2c-mlx. Run:

$ yum remove -y kmod-i2c-mlx
$ modprobe -rv i2c-mlx

Transfer the i2c-mlx RPM from the BlueField software tarball under distro/SRPM onto the Arm. Run:

$ rpmbuild --rebuild /root/i2c-mlx-1.0-0.g422740c.src.rpm
$ yum install -y /root/rpmbuild/RPMS/aarch64/i2c-mlx-1.0-0.g422740c_5.4.17_mlnx.9.ga0bea68.aarch64.rpm
$ ls -l /lib/modules/$(uname -r)/extra/i2c-mlx/i2c-mlx.ko

Load i2c-mlx. Run:
```
$ modprobe i2c-mlx
```

Install the following packages:

$ yum install ipmitool lm_sensors

If the above operation fails for ipmitool, run the following to install it:

wget http://sourceforge.net/projects/ipmitool/files/ipmitool/1.8.18/ipmitool-1.8.18.tar.gz 
tar -xvzf ipmitool-1.8.18.tar.gz 
cd ipmitool-1.8.18
./bootstrap
./configure
make
make install DESTDIR=/tmp/package-ipmitool

The i2c-tools package is also required, but the version contained in the CentOS Yum repository is old and does not work with BlueField. Therefore, please download i2c-tools version 4.1, and then build and install it.

# Build i2c-tools from a newer source
wget http://mirrors.edge.kernel.org/pub/software/utils/i2c-tools/i2c-tools-4.1.tar.gz
tar -xvzf i2c-tools-4.1.tar.gz
cd i2c-tools-4.1
make
make install PREFIX=/usr

# create a link to the libraries
ln -sfn /usr/lib/libi2c.so.0.1.1 /lib64/libi2c.so
ln -sfn /usr/lib/libi2c.so.0.1.1 /lib64/libi2c.so.0

Generate an RPM binary from the BlueField's mlx-OpenIPMI-2.0.25 source RPM.

The following packages might be needed to build the binary RPM depending on which version of CentOS you are using.
```
$ yum install libtool rpm-devel rpmdevtools rpmlint wget ncurses-devel automake
$ rpmbuild --rebuild mlx-OpenIPMI-2.0.25-0.g581ebbb.src.rpm
```
You may obtain this rpm file by means of scp from the server host's Bluefield Distribution folder. For example:
$ scp <BF_INST_DIR>/distro/SRPMS/mlx-OpenIPMI-2.0.25-0.g4fdc53d.src.rpm <ip-address>:/<target_directory>/
If there are issues with building the OpenIPMI RPM, verify that the swig package is not installed.
```
$ yum remove -y swig
```
Generate a binary RPM from the ipmb-dev-int source RPM and install it. Run:
```
$ rpmbuild --rebuild ipmb-dev-int-1.0-0.g304ea0c.src.rpm
```
Generate a binary RPM from the ipmb-host source RPM and install it. Run:
```
$ rpmbuild --rebuild ipmb-host-1.0-0.g304ea0c.src.rpm
```

Load OpenIPMI, ipmb-host, and ipmb-dev-int RPM packages. Run:

$ yum install -y /root/rpmbuild/RPMS/aarch64/mlx-OpenIPMI-2.0.25-0.g581ebbb_5.4.0_49.el7a.aarch64.aarch64.rpm
$ yum install -y /root/rpmbuild/RPMS/aarch64/ipmb-dev-int-1.0-0.g304ea0c_5.4.0_49.el7a.aarch64.aarch64.rpm
$ yum install -y /root/rpmbuild/RPMS/aarch64/ipmb-host-1.0-0.g304ea0c_5.4.0_49.el7a.aarch64.aarch64.rpm

Load the IPMB driver. Run:
```
$ modprobe ipmb-dev-int
```

Install and start rasdaemon package. Run:

yum install rasdaemon
systemctl enable rasdaemon
systemctl start rasdaemon

Start the IPMI daemon. Run:

$ systemctl enable mlx_ipmid
$ systemctl start mlx_ipmid
$ systemctl enable set_emu_param
$ systemctl start set_emu_param

Last updated: February 05, 2025