What:		/sys/kernel/debug/iommu/intel/iommu_regset
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file dumps all the register contents for each IOMMU device.

		Example in Kabylake:

		::

		 $ sudo cat /sys/kernel/debug/iommu/intel/iommu_regset

		 IOMMU: dmar0 Register Base Address: 26be37000

		 Name                    Offset          Contents
		 VER                     0x00            0x0000000000000010
		 GCMD                    0x18            0x0000000000000000
		 GSTS                    0x1c            0x00000000c7000000
		 FSTS                    0x34            0x0000000000000000
		 FECTL                   0x38            0x0000000000000000

		 [...]

		 IOMMU: dmar1 Register Base Address: fed90000

		 Name                    Offset          Contents
		 VER                     0x00            0x0000000000000010
		 GCMD                    0x18            0x0000000000000000
		 GSTS                    0x1c            0x00000000c7000000
		 FSTS                    0x34            0x0000000000000000
		 FECTL                   0x38            0x0000000000000000

		 [...]

		 IOMMU: dmar2 Register Base Address: fed91000

		 Name                    Offset          Contents
		 VER                     0x00            0x0000000000000010
		 GCMD                    0x18            0x0000000000000000
		 GSTS                    0x1c            0x00000000c7000000
		 FSTS                    0x34            0x0000000000000000
		 FECTL                   0x38            0x0000000000000000

		 [...]

What:		/sys/kernel/debug/iommu/intel/ir_translation_struct
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file dumps the table entries for Interrupt
		remapping and Interrupt posting.

		Example in Kabylake:

		::

		 $ sudo cat /sys/kernel/debug/iommu/intel/ir_translation_struct

		 Remapped Interrupt supported on IOMMU: dmar0
		 IR table address:100900000

		 Entry SrcID   DstID    Vct IRTE_high           IRTE_low
		 0     00:0a.0 00000080 24  0000000000040050    000000800024000d
		 1     00:0a.0 00000001 ef  0000000000040050    0000000100ef000d

		 Remapped Interrupt supported on IOMMU: dmar1
		 IR table address:100300000
		 Entry SrcID   DstID    Vct IRTE_high           IRTE_low
		 0     00:02.0 00000002 26  0000000000040010    000000020026000d

		 [...]

		 ****

		 Posted Interrupt supported on IOMMU: dmar0
		 IR table address:100900000
		 Entry SrcID   PDA_high PDA_low  Vct IRTE_high          IRTE_low

What:		/sys/kernel/debug/iommu/intel/dmar_translation_struct
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file dumps Intel IOMMU DMA remapping tables, such
		as root table, context table, PASID directory and PASID
		table entries in debugfs. For legacy mode, it doesn't
		support PASID, and hence PASID field is defaulted to
		'-1' and other PASID related fields are invalid.

		Example in Kabylake:

		::

		 $ sudo cat /sys/kernel/debug/iommu/intel/dmar_translation_struct

		 IOMMU dmar1: Root Table Address: 0x103027000
		 B.D.F   Root_entry
		 00:02.0 0x0000000000000000:0x000000010303e001

		 Context_entry
		 0x0000000000000102:0x000000010303f005

		 PASID   PASID_table_entry
		 -1      0x0000000000000000:0x0000000000000000:0x0000000000000000

		 IOMMU dmar0: Root Table Address: 0x103028000
		 B.D.F   Root_entry
		 00:0a.0 0x0000000000000000:0x00000001038a7001

		 Context_entry
		 0x0000000000000000:0x0000000103220e7d

		 PASID   PASID_table_entry
		 0       0x0000000000000000:0x0000000000800002:0x00000001038a5089

		 [...]

What:		/sys/kernel/debug/iommu/intel/invalidation_queue
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file exports invalidation queue internals of each
		IOMMU device.

		Example in Kabylake:

		::

		 $ sudo cat /sys/kernel/debug/iommu/intel/invalidation_queue

		 Invalidation queue on IOMMU: dmar0
		 Base: 0x10022e000      Head: 20        Tail: 20
		 Index          qw0                    qw1                     qw2
		     0   0000000000000014        0000000000000000        0000000000000000
		     1   0000000200000025        0000000100059c04        0000000000000000
		     2   0000000000000014        0000000000000000        0000000000000000

				qw3                  status
			 0000000000000000        0000000000000000
			 0000000000000000        0000000000000000
			 0000000000000000        0000000000000000

		 [...]

		 Invalidation queue on IOMMU: dmar1
		 Base: 0x10026e000      Head: 32        Tail: 32
		 Index           qw0                     qw1                   status
		     0   0000000000000004        0000000000000000         0000000000000000
		     1   0000000200000025        0000000100059804         0000000000000000
		     2   0000000000000011        0000000000000000         0000000000000000

		 [...]

What:		/sys/kernel/debug/iommu/intel/dmar_perf_latency
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file is used to control and show counts of
		execution time ranges for various types per DMAR.

		Firstly, write a value to
		/sys/kernel/debug/iommu/intel/dmar_perf_latency
		to enable sampling.

		The possible values are as follows:

		* 0 - disable sampling all latency data

		* 1 - enable sampling IOTLB invalidation latency data

		* 2 - enable sampling devTLB invalidation latency data

		* 3 - enable sampling intr entry cache invalidation latency data

		Next, read /sys/kernel/debug/iommu/intel/dmar_perf_latency gives
		a snapshot of sampling result of all enabled monitors.

		Examples in Kabylake:

		::

		 1) Disable sampling all latency data:

		 $ sudo echo 0 > /sys/kernel/debug/iommu/intel/dmar_perf_latency

		 2) Enable sampling IOTLB invalidation latency data

		 $ sudo echo 1 > /sys/kernel/debug/iommu/intel/dmar_perf_latency

		 $ sudo cat /sys/kernel/debug/iommu/intel/dmar_perf_latency

		 IOMMU: dmar0 Register Base Address: 26be37000
				 <0.1us   0.1us-1us    1us-10us  10us-100us   100us-1ms
		 inv_iotlb           0           0           0           0           0

				 1ms-10ms      >=10ms     min(us)     max(us) average(us)
		 inv_iotlb           0           0           0           0           0

		 [...]

		 IOMMU: dmar2 Register Base Address: fed91000
				 <0.1us   0.1us-1us    1us-10us  10us-100us   100us-1ms
		 inv_iotlb           0           0          18           0           0

				 1ms-10ms      >=10ms     min(us)     max(us) average(us)
		 inv_iotlb           0           0           2           2           2

		 3) Enable sampling devTLB invalidation latency data

		 $ sudo echo 2 > /sys/kernel/debug/iommu/intel/dmar_perf_latency

		 $ sudo cat /sys/kernel/debug/iommu/intel/dmar_perf_latency

		 IOMMU: dmar0 Register Base Address: 26be37000
				 <0.1us   0.1us-1us    1us-10us  10us-100us   100us-1ms
		 inv_devtlb           0           0           0           0           0

				 >=10ms     min(us)     max(us) average(us)
		 inv_devtlb           0           0           0           0

		 [...]

What:		/sys/kernel/debug/iommu/intel/<bdf>/domain_translation_struct
Date:		December 2023
Contact:	Jingqi Liu <Jingqi.liu@intel.com>
Description:
		This file dumps a specified page table of Intel IOMMU
		in legacy mode or scalable mode.

		For a device that only supports legacy mode, dump its
		page table by the debugfs file in the debugfs device
		directory. e.g.
		/sys/kernel/debug/iommu/intel/0000:00:02.0/domain_translation_struct.

		For a device that supports scalable mode, dump the
		page table of specified pasid by the debugfs file in
		the debugfs pasid directory. e.g.
		/sys/kernel/debug/iommu/intel/0000:00:02.0/1/domain_translation_struct.

		Examples in Kabylake:

		::

		 1) Dump the page table of device "0000:00:02.0" that only supports legacy mode.

		 $ sudo cat /sys/kernel/debug/iommu/intel/0000:00:02.0/domain_translation_struct

		 Device 0000:00:02.0 @0x1017f8000
		 IOVA_PFN                PML5E                   PML4E
		 0x000000008d800 |       0x0000000000000000      0x00000001017f9003
		 0x000000008d801 |       0x0000000000000000      0x00000001017f9003
		 0x000000008d802 |       0x0000000000000000      0x00000001017f9003

		 PDPE                    PDE                     PTE
		 0x00000001017fa003      0x00000001017fb003      0x000000008d800003
		 0x00000001017fa003      0x00000001017fb003      0x000000008d801003
		 0x00000001017fa003      0x00000001017fb003      0x000000008d802003

		 [...]

		 2) Dump the page table of device "0000:00:0a.0" with PASID "1" that
		 supports scalable mode.

		 $ sudo cat /sys/kernel/debug/iommu/intel/0000:00:0a.0/1/domain_translation_struct

		 Device 0000:00:0a.0 with pasid 1 @0x10c112000
		 IOVA_PFN                PML5E                   PML4E
		 0x0000000000000 |       0x0000000000000000      0x000000010df93003
		 0x0000000000001 |       0x0000000000000000      0x000000010df93003
		 0x0000000000002 |       0x0000000000000000      0x000000010df93003

		 PDPE                    PDE                     PTE
		 0x0000000106ae6003      0x0000000104b38003      0x0000000147c00803
		 0x0000000106ae6003      0x0000000104b38003      0x0000000147c01803
		 0x0000000106ae6003      0x0000000104b38003      0x0000000147c02803

		 [...]