iommu/amd: Add helper function to check GIOSUP/GTSUP

amd_iommu_gt_ppr_supported() only checks for GTSUP. To support PASID
with V2 page table we need GIOSUP as well. Hence add new helper function
to check GIOSUP/GTSUP.

Signed-off-by: Vasant Hegde <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: hegdevasant

drivers/iommu/amd/amd_iommu.h

@@ -118,9 +118,14 @@ static inline bool check_feature2(u64 mask)
 	return (amd_iommu_efr2 & mask);
 }
 
+static inline bool amd_iommu_v2_pgtbl_supported(void)
+{
+	return (check_feature(FEATURE_GIOSUP) && check_feature(FEATURE_GT));
+}
+
 static inline bool amd_iommu_gt_ppr_supported(void)
 {
-	return (check_feature(FEATURE_GT) &&
+	return (amd_iommu_v2_pgtbl_supported() &&
 		check_feature(FEATURE_PPR) &&
 		check_feature(FEATURE_EPHSUP));
 }

drivers/iommu/amd/init.c

@@ -2071,8 +2071,7 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 	init_iommu_perf_ctr(iommu);
 
 	if (amd_iommu_pgtable == AMD_IOMMU_V2) {
-		if (!check_feature(FEATURE_GIOSUP) ||
-		    !check_feature(FEATURE_GT)) {
+		if (!amd_iommu_v2_pgtbl_supported()) {
 			pr_warn("Cannot enable v2 page table for DMA-API. Fallback to v1.\n");
 			amd_iommu_pgtable = AMD_IOMMU_V1;
 		}