This is as done as lsiommu can ever be, or at least as far as I’m concerned so it’s a release time:

https://github.com/puavo-org/lsiommu/releases/tag/1.0.0

I.e. I spent last night making it do less from the almost nothing it was doing already ;-) That’s the point of these tools…

That enumerated to:

• Reverted back to heap sort.
• Carved 64 kB of data section for JSON builder.
• Hammered STRING_BUFFER() to migrate most of the strings to stack (except JSON builder
• Bunch of fixes…

This sums up to zero mallocs from the main application (while libudev probably does bunch of them when not compiled with make DISCOVER=sysfs).

Motivation to do was this shitty python script:

#!/usr/bin/env python3
#
# Copyright (c) 2022-2023 Jarkko Sakkinen <jarkko.sakkinen@iki.fi>

import os
import sys

IOMMU_SYSFS = '/sys/kernel/iommu_groups'
IOMMU_GROUP_MAX = 128 # an arbitrary choice

def get_iommu_devices():
    groups = [None for group in range(IOMMU_GROUP_MAX)]

    with os.scandir(IOMMU_SYSFS) as group_it:
        for group in group_it:
            devices = []

            group_sysfs = IOMMU_SYSFS + '/' + group.name + '/devices'
            with os.scandir(group_sysfs) as device_it:
                for device in device_it:
                    devices.append(device.name)

            index = int(group.name)
            if index >= IOMMU_GROUP_MAX:
                print('Overflow')
                sys.exit(1)

            groups[index] = devices

    return groups

if __name__ == "__main__":
    groups = get_iommu_devices()

    for i in range(len(groups)):
        group = groups[i]
        if group == None:
            break

        print('IOMMU Group %d' % (i))

        group.sort()

        for device in group:
            # FIXME: Replace with pure Python code:
            os.system('lspci -nns ' + device)

#linux #kernel #iommu #kvm