iommu/amd: Get the maximum number of PASIDs supported
Read the number of PASIDs supported by each IOMMU in the
system and take the smallest number as the maximum value
supported by the IOMMU driver.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 17e0f77..fb4afd6 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -141,6 +141,8 @@
bool amd_iommu_np_cache __read_mostly;
bool amd_iommu_iotlb_sup __read_mostly = true;
+u32 amd_iommu_max_pasids __read_mostly = ~0;
+
/*
* The ACPI table parsing functions set this variable on an error
*/
@@ -699,6 +701,17 @@
iommu->features = ((u64)high << 32) | low;
+ if (iommu_feature(iommu, FEATURE_GT)) {
+ u32 pasids;
+ u64 shift;
+
+ shift = iommu->features & FEATURE_PASID_MASK;
+ shift >>= FEATURE_PASID_SHIFT;
+ pasids = (1 << shift);
+
+ amd_iommu_max_pasids = min(amd_iommu_max_pasids, pasids);
+ }
+
if (!is_rd890_iommu(iommu->dev))
return;