3569dd07aa
The Intel IOMMU driver opportunistically skips a few top level page
tables from the domain paging directory while programming the IOMMU
context entry. However there is an implicit assumption in the code that
domain's adjusted guest address width (agaw) would always be greater
than IOMMU's agaw.
The IOMMU capabilities in an upcoming platform cause the domain's agaw
to be lower than IOMMU's agaw. The issue is seen when the IOMMU supports
both 4-level and 5-level paging. The domain builds a 4-level page table
based on agaw of 2. However the IOMMU's agaw is set as 3 (5-level). In
this case the code incorrectly tries to skip page page table levels.
This causes the IOMMU driver to avoid programming the context entry. The
fix handles this case and programs the context entry accordingly.
Fixes: de24e55395698 ("iommu/vt-d: Simplify domain_context_mapping_one")
Cc: <stable@vger.kernel.org>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reported-by: Ramos Falcon, Ernesto R <ernesto.r.ramos.falcon@intel.com>
Tested-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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.