dd5142ca5d
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> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.