SoC Management Interface

1.0

The SoC management interface, formerly known as RShim, allows an external agent such as the host CPU or BMC to operate the DPU and monitor its operational state. This interface allows provisioning of the DPU, resetting Arm cores, and obtaining logs.

Warning

For instructions for Windows support, please refer to page "Windows Support".

Please refer to section Updating Repo Package on Host Side.

Configuration File

The configuration file for the SoC management interface is located at /etc/rshim.conf and includes the parameters listed in the table below.

Parameter

Default

Description

BOOT_TIMEOUT

150

Timeout value in seconds when pushing BFB while Arm side is not reading the boot stream.

DROP_MODE

0

Once set to 1, the RShim driver ignores all RShim writes and returns 0 for RShim read.

This is used in cases such as during FW_RESET or bypassing the RShim PF to VM.

PCIE_RESET_DELAY

10

Delay in seconds for RShim over PCIe, which is added after chip reset and before pushing the boot stream.

PCIE_INTR_POLL_INTERVAL

10

Interrupt polling interval in seconds when running RShim over direct memory mapping.

PCIE_HAS_VFIO

1

Setting this parameter to 0 disallows RShim memory mapping via VFIO.

PCIE_HAS_UIO

1

Setting this parameter to 0 disallows RShim memory mapping via UIO.

Warning

Configuring RShim is optional. The default parameters are designed to support out-of-box deployment scenarios including multiple DPUs on a single host.

Users may control which RShim index maps to which device by following this procedure:

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# Uncomment the 'rshim<N>' line to configure the mapping. # # device-name pci-device rshim0      pcie-0000:21:00.2 rshim1      pcie-0000:81:00.2   # # Ignored devices. # Uncomment the 'none' line to configure the ignored devices. # #none         usb-1-1.4 #none         pcie-lf-0000:84:00.0

Warning

If any of these configurations are changed, then the SoC management interface must be restarted by running:

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systemctl restart rshim


The NVIDIA® BlueField® DPU registers on the host OS a "DMA controller" for DPU management over PCIe. This can be verified by running the following:

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#  lspci -d 15b3: | grep 'SoC Management Interface' 27:00.2 DMA controller: Mellanox Technologies MT42822 BlueField-2 SoC Management Interface (rev 01)

A special SoC management driver must be installed and run on the host OS to expose the various BlueField management interfaces to the OS. Currently, this driver is named RShim and is automatically installed as part of the DOCA installation. Refer to section "Install RShim on Host" for information on how to obtain and install the host-side SoC management interface driver .

When the SoC management interface driver runs properly on the host side, a sysfs device, /dev/rshim0/*, and a virtual Ethernet interface, tmfifo_net0, become available. The following is an example for querying the status of the SoC management interface driver on the host side:

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# systemctl status rshim ● rshim.service - rshim driver for BlueField SoC Loaded: loaded (/lib/systemd/system/rshim.service; disabled; vendor preset: enabled) Active: active (running) since Tue 2022-05-31 14:57:07 IDT; 1 day 1h ago Docs: man:rshim(8) Process: 90322 ExecStart=/usr/sbin/rshim $OPTIONS (code=exited, status=0/SUCCESS) Main PID: 90323 (rshim) Tasks: 11 (limit: 76853) Memory: 3.3M CGroup: /system.slice/rshim.service └─90323 /usr/sbin/rshim May 31 14:57:07 … systemd[1]: Starting rshim driver for BlueField SoC... May 31 14:57:07 … systemd[1]: Started rshim driver for BlueField SoC. May 31 14:57:07 … rshim[90323]: Probing pcie-0000:a3:00.2(vfio) May 31 14:57:07 … rshim[90323]: Create rshim pcie-0000:a3:00.2 May 31 14:57:07 … rshim[90323]: rshim pcie-0000:a3:00.2 enable May 31 14:57:08 … rshim[90323]: rshim0 attached

If the SoC management interface driver device does not appear, refer to section "RShim Troubleshooting and How-Tos".

Virtual Ethernet Interface

On the host, the SoC management interface driver exposes a virtual Ethernet device called tmfifo_net0. This virtual Ethernet can be thought of as a peer-to-peer tunnel connection between the host and the DPU OS. The DPU OS also configures a similar device. The DPU OS's BFB images are customized to configure the DPU side of this connection with a preset IP of 192.168.100.2/30. It is up to the user to configure the host side of this connection. Configuration procedures vary for different OSs.

The following example configures the host side of tmfifo_net0 with a static IP and enables IPv4-based communication to the DPU OS:

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#  ip addr add dev tmfifo_net0 192.168.100.1/30

Warning

For instructions on persistent IP configuration of the tmfifo_net0 interface, refer to step "Assign a static IP to tmfifo_net0" under "Updating Repo Package on Host Side".

Logging in from the host to the DPU OS is now possible over the virtual Ethernet. For example:

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ssh ubuntu@192.168.100.2


SoC Management Interface Driver Support for Multiple DPUs

Multiple DPUs may connect to the same host machine. When the SoC management interface driver is loaded and operating correctly, each BlueField device is expected to have its own device directory on sysfs, /dev/rshim<N>, and a virtual Ethernet device, tmfifo_net<N>.

Note

<N> correlates to the number of BlueField DPUs used where the SoC management interfaces of the first DPU is 0, incrementing by 1 for each added BlueField.

The following are some guidelines on how to set up the SoC management virtual Ethernet interfaces properly if multiple DPUs are installed in the host system.

There are two methods to manage multiple tmfifo_net interfaces on a Linux platform:

  • Using a bridge, with all tmfifo_net<N> interfaces on the bridge – the bridge device bares a single IP address on the host while each DPU has unique IP in the same subnet as the bridge

  • Directly over the individual tmfifo_net<N> – each interface has a unique subnet IP and each DPU has a corresponding IP per subnet

Whichever method is selected, the host-side tmfifo_net interfaces should have different MAC addresses, which can be:

  • Configured using ifconfig. For example:

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    $ ifconfig tmfifo_net0 192.168.100.1/24 hw ether 02:02:02:02:02:02

  • Or saved in configuration via the /udev/rules as can be seen later in this section.

In addition, each Arm-side tmfifo_net interface must have a unique MAC and IP address configuration, as BlueField OS comes uniformly pre-configured with a generic MAC, and 192.168.100.2. The latter must be configured in each DPU manually or by DPU customization scripts during BlueField OS installation.

Multi-board Management Example

This example deals with two BlueField DPUs installed on the same server (the process is similar for more DPUs). The example assumes that the RShim package has been installed on the host server.

Configuring Management Interface on Host

Warning

This example is relevant for CentOS/RHEL operating systems only.

  1. Create a bf_tmfifo interface under /etc/sysconfig/network-scripts. Run:

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    vim /etc/sysconfig/network-scripts/ifcfg-br_tmfifo

  2. Inside ifcfg-br_tmfifo, insert the following content:

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    DEVICE="br_tmfifo" BOOTPROTO="static" IPADDR="192.168.100.1" NETMASK="255.255.255.0" ONBOOT="yes" TYPE="Bridge"

  3. Create a configuration file for the first BlueField DPU, tmfifo_net0. Run:

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    vim /etc/sysconfig/network-scripts/ifcfg-tmfifo_net0

  4. Inside ifcfg-tmfifo_net0, insert the following content:

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    DEVICE=tmfifo_net0 BOOTPROTO=none ONBOOT=yes NM_CONTROLLED=no BRIDGE=br_tmfifo

  5. Create a configuration file for the second BlueField DPU, tmfifo_net1. Run:

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    DEVICE=tmfifo_net1 BOOTPROTO=none ONBOOT=yes NM_CONTROLLED=no BRIDGE=br_tmfifo

  6. Create the rules for the tmfifo_net interfaces. Run:

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    vim /etc/udev/rules.d/91-tmfifo_net.rules

  7. Restart the network for the changes to take effect. Run:

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    # /etc/init.d/network restart Restarting network (via systemctl): [ OK ]

Configuring BlueField DPU Side

BlueField DPUs arrive with the following factory default configurations for tmfifo_net0.

Address

Value

MAC

00:1a:ca:ff:ff:01

IP

192.168.100.2

Therefore, if you are working with more than one DPU, you must change the default MAC and IP addresses.

Updating RShim Network MAC Address

Warning

This procedure is relevant for Ubuntu/Debian (sudo needed), and CentOS BFBs. The procedure only affects the tmfifo_net0 on the Arm side.

  1. Use a Linux console application (e.g. screen or minicom) to log into each BlueField. For example:

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    # sudo screen /dev/rshim<0|1>/console 115200

  2. Create a configuration file for tmfifo_net0 MAC address. Run:

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    # sudo vi /etc/bf.cfg

  3. Inside bf.cfg, insert the new MAC:

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    NET_RSHIM_MAC=00:1a:ca:ff:ff:03

  4. Apply the new MAC address. Run:

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    sudo bfcfg

  5. Repeat this procedure for the second BlueField DPU (using a different MAC address).

    Note

    Arm must be rebooted for this configuration to take effect. It is recommended to update the IP address before you do that to avoid unnecessary reboots.

Warning

For comprehensive list of the supported parameters to customize bf.cfg during BFB installation, refer to section "bf.cfg Parameters".


Updating IP Address

For Ubuntu:

  1. Access the file 50-cloud-init.yaml and modify the tmfifo_net0 IP address:

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    sudo vim /etc/netplan/50-cloud-init.yaml   tmfifo_net0: addresses: - 192.168.100.2/30 ===>>> 192.168.100.3/30

  2. Reboot the Arm. Run:

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    sudo reboot

  3. Repeat this procedure for the second BlueField DPU (using a different IP address).

    Note

    Arm must be rebooted for this configuration to take effect. It is recommended to update the MAC address before you do that to avoid unnecessary reboots.

For CentOS:

  1. Access the file ifcfg-tmfifo_net0. Run:

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    # vim /etc/sysconfig/network-scripts/ifcfg-tmfifo_net0

  2. Modify the value for IPADDR:

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    IPADDR=192.168.100.3

  3. Reboot the Arm. Run:

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    reboot

    Or perform netplan apply.

  4. Repeat this procedure for the second BlueField DPU (using a different IP address).

    Note

    Arm must be rebooted for this configuration to take effect. It is recommended to update the MAC address before you do that to avoid unnecessary reboots.

Permanently Changing Arm-side MAC Address

Warning

It is assumed that the commands in this section are executed with root (or sudo) permission.

The default MAC address is 00:1a:ca:ff:ff:01. It can be changed using ifconfig or by updating the UEFI variable as follows:

  1. Log into Linux from the Arm console.

  2. Run:

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    $ "ls /sys/firmware/efi/efivars".

  3. If not mounted, run:

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    $ mount -t efivarfs none /sys/firmware/efi/efivars $ chattr -i /sys/firmware/efi/efivars/RshimMacAddr-8be4df61-93ca-11d2-aa0d-00e098032b8c $ printf "\x07\x00\x00\x00\x00\x1a\xca\xff\xff\x03" > \ /sys/firmware/efi/efivars/RshimMacAddr-8be4df61-93ca-11d2-aa0d-00e098032b8c

The printf command sets the MAC address to 00:1a:ca:ff:ff:03 (the last six bytes of the printf value). Either reboot the device or reload the tmfifo driver for the change to take effect.

The MAC address can also be updated from the server host side while the Arm-side Linux is running:

  1. Enable the configuration. Run:

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    # echo "DISPLAY_LEVEL 1" > /dev/rshim0/misc

  2. Display the current setting. Run:

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    # cat /dev/rshim0/misc DISPLAY_LEVEL 1 (0:basic, 1:advanced, 2:log) BOOT_MODE 1 (0:rshim, 1:emmc, 2:emmc-boot-swap) BOOT_TIMEOUT 300 (seconds) DROP_MODE 0 (0:normal, 1:drop) SW_RESET 0 (1: reset) DEV_NAME pcie-0000:04:00.2 DEV_INFO BlueField-2(Rev 1) PEER_MAC 00:1a:ca:ff:ff:01 (rw) PXE_ID 0x00000000 (rw) VLAN_ID 0 0 (rw)

  3. Modify the MAC address. Run:

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    $ echo "PEER_MAC xx:xx:xx:xx:xx:xx" > /dev/rshim0/misc

For more information and an example of the script that covers multiple DPU installation and configuration, refer to section "Installing Full DOCA Image on Multiple DPUs" of the NVIDIA DOCA Installation Guide.

Function

Command

Comments

1

Push BFB

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bfb-install –r rshim<N> -b <bfb> [-c bf.cfg]

Using bf.cfg in the command is optional. For more details about bf.cfg, refer to section "DPU Configuration File".

2

Open console

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screen /dev/rshim<N>/console 115200 minicom -D /dev/rshim<N>/console

The N index depends on the number of DPUs in your setup.

Use Linux's screen or minicom console applications to access the BlueField console.

3

Configure a virtual network interface

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ip addr add dev tmfifo_net<N> 192.168.100.1/30

The N index depends on the number of DPUs in your setup. Refer to section "SoC Management Interface Driver Support for Multiple DPUs" for more information.

The default IP address for the DPU is 192.168.100.2/30.

The IP used in the command (192.168.100.1/30) is for example purposes only.

4

Log into the DPU

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ssh -6  user@fe80::21a:caff:feff:ff01%tmfifo_net<N>

The N index depends on the number of DPUs in your setup. Refer to section "SoC Management Interface Driver Support for Multiple DPUs" for more information.

5

PXE boot over RShim

N/A

Please refer to section "Deploying BlueField Software Using BFB with PXE" for more information.

6

Issue Arm software reset

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echo "SW_RESERT 1" > /dev/rshim<N>/misc

7

Expose log messages

N/A

For more information, please refer to section "Logging".

The bf.cfg file contains configuration that can be pushed to customize the installation of the BFB.

Please see section "bf.cfg Parameters" for the bf.cfg file contents.

© Copyright 2023, NVIDIA. Last updated on Nov 21, 2023.