iommu/vt-d: Remove caching mode check before device TLB flush

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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 <29b3283972> ("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>

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This commit is contained in:

Lu Baolu 2024-04-24 15:16:32 +08:00 • committed by Joerg Roedel

parent 621b7e54f2

commit 304b3bde24

1 changed files with 2 additions and 7 deletions

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drivers/iommu/intel/iommu.c

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