NVIDIA/mctp-utils

NVIDIA/mctp-utils

Description: MCTP tool running on Host to communicate with devices via USB and other transport layers.

Language: Python

License: NOASSERTION

Stars: 1

Forks: 1

Open issues: 0

Created: 2026-05-28T03:29:31Z

Pushed: 2026-07-24T09:34:08Z

Default branch: main

Fork: no

Archived: no

README:

Table of Contents

• [Setup](#setup)
• [Prerequisites](#prerequisites)
• [Linux udev rules](#linux-udev-rules-for-usb-devices)
• [Usage](#usage)
• [Run via uv](#run-via-uv)
• [Direct file invocation](#direct-file-invocation)
• [Subcommands](#subcommands)
• [Fuse validation](#fuse-validation)
• [Debug](#debug)
• [ModuleNotFoundError when running directly](#modulenotfounderror-when-running-directly)
• [cffi build fails during uv sync](#cffi-build-fails-during-uv-sync)

Setup

Prerequisites

• Require Python ≥ 3.10
• Require uv

$ curl -LsSf https://astral.sh/uv/install.sh | sh

• Install Python dependencies at the root of mctp-utils:

$ uv sync

💡 Notes:

• If you encounter pyproject.toml not found error, check your working directory — run uv sync at the root of mctp-utils.
• uv sync creates .venv/ and installs every dependency exactly as pinned in uv.lock.
• Install libusb (Linux: preinstalled on most distros; install only if missing):

$ sudo apt-get update && sudo apt-get install -y libusb-1.0-0

Linux udev rules (for USB devices)

Required for non-root access to MCU devices over USB:

echo 'SUBSYSTEM=="usb", ENV{DEVTYPE}=="usb_device", ATTR{idVendor}=="0955", MODE="0666"' | sudo tee /etc/udev/rules.d/99-nv-mcu.rules
sudo udevadm control --reload-rules
sudo udevadm trigger

Usage

Option1: Run via uv (Recommended)

uv run python -m mctp_utils # list subcommands
uv run python -m mctp_utils mctp_cmd_utils --help

Option2: Direct file invocation

uv run python mctp_utils/mctp_cmd_utils.py --help

Useful for debugging a single utility in isolation.

Subcommands

| Subcommand | Purpose | |---|---| | mctp_cmd_utils | MCTP raw commands, EID management, routing | | mctp_nsm_utils | NVIDIA Server Management MCTP utility | | mctp_pldm_utils | PLDM transport over MCTP | | mctp_spdm_utils | SPDM (certificates, measurements) over MCTP | | mctp_vdm_utils | Vendor Defined Messages over MCTP | | mfghelper | Manufacturing helper |

Fuse validation

Use etc/fuses_mcxn556_pqc_no_rotkh.json as a sanitized reference for the fuse JSON format. The file keeps the measured MCXN556 fuse order, but addresses 11 through 22 contain zero ROTKH placeholders. Replace those words with the project/keyset ROTKH values from the matching provisioning package before using the file to validate a real device.

To calculate the expected fuse measurement from a JSON file:

uv run python -m mctp_utils mfghelper measure_fuse \
--fuse_cfg etc/fuses_mcxn556_pqc_no_rotkh.json

To verify a device over USB/MCTP:

uv run python -m mctp_utils mfghelper \
--bus_num \
--dev_num \
--tcp_port 5000 \
--context spdm_context_status.json \
verify_fuse \
--fuse_cfg

Mechanism: mfghelper reads the top-level fuses array in order, applies the helper fuse mask, serializes each 32-bit value as little-endian bytes, and computes a SHA384 digest. verify_fuse reads SPDM measurement index 13 from the device and compares that device digest with the expected digest from the JSON; firmware patch 215 and newer use the masked calculation.

Debug

ModuleNotFoundError when running directly

Use uv run python ... rather than bare python ... — uv run activates the venv so the package can find its dependencies. Applies to both -m mctp_utils invocation and direct file invocation.

cffi build fails during uv sync

On Ubuntu/Debian: sudo apt install libffi-dev. On Fedora: sudo dnf install libffi-devel. Re-run uv sync.