Quick wrapper script for lspci that lists devices by IOMMU group. Arguments (except -s and -d) are passed through to lspci.

lspci_by_iommu.py

#!/usr/bin/env python3

import os, subprocess, sys
from contextlib import suppress

if "-h" in sys.argv:
    with suppress(subprocess.CalledProcessError):
        print(subprocess.check_output(["lspci", "-h"], universal_newlines=True))
    exit(0)

if "-s" in sys.argv or "-d" in sys.argv:
    print("Do not use -s or -d selectors, the script does that for you.",
          file=sys.stderr)
    exit(1)

groups = sorted(os.scandir("/sys/kernel/iommu_groups"),
                key=lambda de: int(de.name))

for i, group in enumerate(groups):

    assert group.is_dir(follow_symlinks=False)

    if i > 0:
        print()
    print(f"Group {int(group.name):2d}:")

    devicespath = os.path.join(group, "devices")
    devices = sorted(os.scandir(devicespath),
                     key=lambda de: int(de.name.translate(str.maketrans("", "", ":.")), 16))

    for device in devices:

        assert device.is_symlink()
        assert device.is_dir(follow_symlinks=True)

        lspci = subprocess.check_output(["lspci", "-s", device.name] + sys.argv[1:],
                                        stderr=subprocess.STDOUT,
                                        universal_newlines=True)
        print(lspci.strip())

print()