Documentation / ABI / testing / debugfs-amd-iommu


Based on kernel version 6.17. Page generated on 2025-10-03 10:03 EST.

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What:		/sys/kernel/debug/iommu/amd/iommu<x>/mmio
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file provides read/write access for user input. Users specify the
		MMIO register offset for iommu<x>, and the file outputs the corresponding
		MMIO register value of iommu<x>

		Example::

		  $ echo "0x18" > /sys/kernel/debug/iommu/amd/iommu00/mmio
		  $ cat /sys/kernel/debug/iommu/amd/iommu00/mmio

		Output::

		  Offset:0x18 Value:0x000c22000003f48d

What:		/sys/kernel/debug/iommu/amd/iommu<x>/capability
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file provides read/write access for user input. Users specify the
		capability register offset for iommu<x>, and the file outputs the
		corresponding capability register value of iommu<x>.

		Example::

		  $ echo "0x10" > /sys/kernel/debug/iommu/amd/iommu00/capability
		  $ cat /sys/kernel/debug/iommu/amd/iommu00/capability

		Output::

		  Offset:0x10 Value:0x00203040

What:		/sys/kernel/debug/iommu/amd/iommu<x>/cmdbuf
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file is a read-only output file containing iommu<x> command
		buffer entries.

		Examples::

		  $ cat /sys/kernel/debug/iommu/amd/iommu<x>/cmdbuf

		Output::

		  CMD Buffer Head Offset:339 Tail Offset:339
		    0: 00835001 10000001 00003c00 00000000
		    1: 00000000 30000005 fffff003 7fffffff
		    2: 00835001 10000001 00003c01 00000000
		    3: 00000000 30000005 fffff003 7fffffff
		    4: 00835001 10000001 00003c02 00000000
		    5: 00000000 30000005 fffff003 7fffffff
		    6: 00835001 10000001 00003c03 00000000
		    7: 00000000 30000005 fffff003 7fffffff
		    8: 00835001 10000001 00003c04 00000000
		    9: 00000000 30000005 fffff003 7fffffff
		   10: 00835001 10000001 00003c05 00000000
		   11: 00000000 30000005 fffff003 7fffffff
		  [...]

What:		/sys/kernel/debug/iommu/amd/devid
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file provides read/write access for user input. Users specify the
		device ID, which can be used to dump IOMMU data structures such as the
		interrupt remapping table and device table.

		Example:

		1.
		  ::

		    $ echo 0000:01:00.0 > /sys/kernel/debug/iommu/amd/devid
		    $ cat /sys/kernel/debug/iommu/amd/devid

		  Output::

		    0000:01:00.0

		2.
		  ::

		    $ echo 01:00.0 > /sys/kernel/debug/iommu/amd/devid
		    $ cat /sys/kernel/debug/iommu/amd/devid

		  Output::

		    0000:01:00.0

What:		/sys/kernel/debug/iommu/amd/devtbl
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file is a read-only output file containing the device table entry
		for the device ID provided in /sys/kernel/debug/iommu/amd/devid.

		Example::

		  $ cat /sys/kernel/debug/iommu/amd/devtbl

		Output::

		  DeviceId             QWORD[3]         QWORD[2]         QWORD[1]         QWORD[0] iommu
		  0000:01:00.0 0000000000000000 20000001373b8013 0000000000000038 6000000114d7b603 iommu3

What:		/sys/kernel/debug/iommu/amd/irqtbl
Date:		January 2025
Contact:	Dheeraj Kumar Srivastava <dheerajkumar.srivastava@amd.com>
Description:
		This file is a read-only output file containing valid IRT table entries
		for the device ID provided in /sys/kernel/debug/iommu/amd/devid.

		Example::

		  $ cat /sys/kernel/debug/iommu/amd/irqtbl

		Output::

		  DeviceId 0000:01:00.0
		  IRT[0000] 0000000000000020 0000000000000241
		  IRT[0001] 0000000000000020 0000000000000841
		  IRT[0002] 0000000000000020 0000000000002041
		  IRT[0003] 0000000000000020 0000000000008041
		  IRT[0004] 0000000000000020 0000000000020041
		  IRT[0005] 0000000000000020 0000000000080041
		  IRT[0006] 0000000000000020 0000000000200041
		  IRT[0007] 0000000000000020 0000000000800041
		  [...]