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304b3bde24
The Caching Mode (CM) of the Intel IOMMU indicates if the hardware
implementation caches not-present or erroneous translation-structure
entries except for the first-stage translation. The caching mode is
irrelevant to the device TLB, therefore there is no need to check it
before a device TLB invalidation operation.
Remove two caching mode checks before device TLB invalidation in the
driver. The removal of these checks doesn't change the driver's behavior
in critical map/unmap paths. Hence, there is no functionality or
performance impact, especially since commit <29b32839725f> ("iommu/vt-d:
Do not use flush-queue when caching-mode is on") has already disabled
flush-queue for caching mode. Therefore, caching mode will never call
intel_flush_iotlb_all().
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20240415013835.9527-1-baolu.lu@linux.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 reStructuredText 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.