iommu/vt-d: Cache max domain ID to avoid redundant calculation

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The cap_ndoms() helper calculates the maximum available domain ID from
the value of capability register, which can be inefficient if called
repeatedly. Cache the maximum supported domain ID in max_domain_id field
during initialization to avoid redundant calls to cap_ndoms() throughout
the IOMMU driver.

No functionality change.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

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Lu Baolu 2026-08-05 07:43:08 +08:00 • committed by Joerg Roedel

parent 1c677d8a2c

commit 5b3ba0a002

3 changed files with 7 additions and 5 deletions

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1

drivers/iommu/intel/dmar.c

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10

drivers/iommu/intel/iommu.c

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1

drivers/iommu/intel/iommu.h

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