A DMAR table walk would typically follow the below process.
1. Bus number is used to index into root table which points to a context
table.
2. Device number and Function number are used together to index into
context table which then points to a pasid directory.
3. PASID[19:6] is used to index into PASID directory which points to a
PASID table.
4. PASID[5:0] is used to index into PASID table which points to all levels
of page tables.
Whenever a user opens the file
"/sys/kernel/debug/iommu/intel/dmar_translation_struct", the above
described DMAR table walk is performed and the contents of the table are
dumped into the file. The dump could be handy while dealing with devices
that use PASID.
Example of such dump:
cat /sys/kernel/debug/iommu/intel/dmar_translation_struct
(Please note that because of 80 char limit, entries that should have been
in the same line are broken into different lines)
IOMMU dmar0: Root Table Address: 0x436f7c000
B.D.F Root_entry Context_entry
PASID PASID_table_entry
00:0a.0 0x0000000000000000:0x000000044dd3f001 0x0000000000100000:0x0000000435460e1d
0 0x000000044d6e1089:0x0000000000000003:0x0000000000000001
00:0a.0 0x0000000000000000:0x000000044dd3f001 0x0000000000100000:0x0000000435460e1d
1 0x0000000000000049:0x0000000000000001:0x0000000003c0e001
Note that the above format is followed even for legacy DMAR table dump
which doesn't support PASID and hence in such cases PASID is defaulted to
-1 indicating that PASID and it's related fields are invalid.
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Presently, "/sys/kernel/debug/iommu/intel/dmar_translation_struct" file
dumps DMAR tables in the below format
IOMMU dmar2: Root Table Address:4362cc000
Root Table Entries:
Bus: 0 H: 0 L: 4362f0001
Context Table Entries for Bus: 0
Entry B:D.F High Low
160 00:14.0 102 4362ef001
184 00:17.0 302 435ec4001
248 00:1f.0 202 436300001
This format has few short comings like
1. When extended for dumping scalable mode DMAR table it will quickly be
very clumsy, making it unreadable.
2. It has information like the Bus number and Entry which are basically
part of B:D.F, hence are a repetition and are not so useful.
So, change it to a new format which could be easily extended to dump
scalable mode DMAR table. The new format looks as below:
IOMMU dmar2: Root Table Address: 0x436f7d000
B.D.F Root_entry Context_entry
00:14.0 0x0000000000000000:0x0000000436fbd001 0x0000000000000102:0x0000000436fbc001
00:17.0 0x0000000000000000:0x0000000436fbd001 0x0000000000000302:0x0000000436af4001
00:1f.0 0x0000000000000000:0x0000000436fbd001 0x0000000000000202:0x0000000436fcd001
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Sohil Mehta <sohil.mehta@intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Add a new config option CONFIG_INTEL_IOMMU_DEBUGFS and do the base
enabling for Intel IOMMU debugfs.
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Co-Developed-by: Gayatri Kammela <gayatri.kammela@intel.com>
Signed-off-by: Gayatri Kammela <gayatri.kammela@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Sai Praneeth Prakhya