Commit 6e6c6d6b authored Oct 26, 2023 by Lu Baolu Committed by Joerg Roedel Oct 27, 2023

iommu: Avoid unnecessary cache invalidations

The iommu_create_device_direct_mappings() only needs to flush the caches
when the mappings are changed in the affected domain. This is not true
for non-DMA domains, or for devices attached to the domain that have no
reserved regions. To avoid unnecessary cache invalidations, add a check
before iommu_flush_iotlb_all().

Fixes: a48ce36e ("iommu: Prevent RESV_DIRECT devices from blocking domains")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Henry Willard <henry.willard@oracle.com>
Link: https://lore.kernel.org/r/20231026084942.17387-1-baolu.lu@linux.intel.com

Signed-off-by: Joerg Roedel <jroedel@suse.de>

parent 05d3ef8b

drivers/iommu/iommu.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1108,6 +1108,7 @@ static int iommu_create_device_direct_mappings(struct iommu_domain *domain,

		}

		if (!list_empty(&mappings) && iommu_is_dma_domain(domain))
		iommu_flush_iotlb_all(domain);

		out: