diff mbox series

[v1,2/4] iommu/io-pgtable-arm: Force outer cache for page-level MAIR via user flag

Message ID 20240826071641.2691374-3-manojvishy@google.com (mailing list archive)
State New, archived
Headers show
Series vfio/iommu: Flag to allow userspace to set DMA buffers system cacheable | expand

Commit Message

Manoj Vishwanathan Aug. 26, 2024, 7:16 a.m. UTC 
This change introduces a user-accessible flag that allows controlling
the system-level outer cache behavior for mapped buffers.

By setting this flag, the page-level MAIR attribute will be forced to
use the outer cache, potentially improving performance for frequently
accessed data.

Signed-off-by: Manoj Vishwanathan <manojvishy@google.com>
---
 drivers/iommu/io-pgtable-arm.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index f5d9fd1f45bf..31dd6203db96 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -471,6 +471,9 @@  static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
 		else if (prot & IOMMU_CACHE)
 			pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
 				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
+		else if (prot & IOMMU_SYS_CACHE)
+			pte |= (ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE
+				<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
 	}
 
 	/*