iommu/amd: Always enable GCR3TRPMode when supported.

The GCR3TRPMode feature allows the DTE[GCR3TRP] field to be configured
with GPA (instead of SPA). This simplifies the implementation, and is
a pre-requisite for nested translation support.

Therefore, always enable this feature if available.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

Author: ssuthiku-amd

drivers/iommu/amd/amd_iommu_types.h

@@ -108,6 +108,7 @@
 
 /* Extended Feature 2 Bits */
 #define FEATURE_SEVSNPIO_SUP	BIT_ULL(1)
+#define FEATURE_GCR3TRPMODE	BIT_ULL(3)
 #define FEATURE_SNPAVICSUP	GENMASK_ULL(7, 5)
 #define FEATURE_SNPAVICSUP_GAM(x) \
 	(FIELD_GET(FEATURE_SNPAVICSUP, x) == 0x1)
@@ -186,6 +187,7 @@
 #define CONTROL_EPH_EN		45
 #define CONTROL_XT_EN		50
 #define CONTROL_INTCAPXT_EN	51
+#define CONTROL_GCR3TRPMODE	58
 #define CONTROL_IRTCACHEDIS	59
 #define CONTROL_SNPAVIC_EN	61
 

drivers/iommu/amd/init.c

@@ -1122,6 +1122,14 @@ static void iommu_enable_gt(struct amd_iommu *iommu)
 		return;
 
 	iommu_feature_enable(iommu, CONTROL_GT_EN);
+
+	/*
+	 * This feature needs to be enabled prior to a call
+	 * to iommu_snp_enable(). Since this function is called
+	 * in early_enable_iommu(), it is safe to enable here.
+	 */
+	if (check_feature2(FEATURE_GCR3TRPMODE))
+		iommu_feature_enable(iommu, CONTROL_GCR3TRPMODE);
 }
 
 /* sets a specific bit in the device table entry. */