iommu/amd: Add support for Guest IO protection

AMD IOMMU introduces support for Guest I/O protection where the request
from the I/O device without a PASID are treated as if they have PASID 0.

Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20220825063939.8360-8-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd/amd_iommu_types.h

@@ -94,6 +94,7 @@
 #define FEATURE_HE		(1ULL<<8)
 #define FEATURE_PC		(1ULL<<9)
 #define FEATURE_GAM_VAPIC	(1ULL<<21)
+#define FEATURE_GIOSUP		(1ULL<<48)
 #define FEATURE_EPHSUP		(1ULL<<50)
 #define FEATURE_SNP		(1ULL<<63)
 
@@ -378,6 +379,7 @@
 #define DTE_FLAG_IW (1ULL << 62)
 
 #define DTE_FLAG_IOTLB	(1ULL << 32)
+#define DTE_FLAG_GIOV	(1ULL << 54)
 #define DTE_FLAG_GV	(1ULL << 55)
 #define DTE_FLAG_MASK	(0x3ffULL << 32)
 #define DTE_GLX_SHIFT	(56)
@@ -436,6 +438,7 @@
 #define PD_PASSTHROUGH_MASK	(1UL << 2) /* domain has no page
 					      translation */
 #define PD_IOMMUV2_MASK		(1UL << 3) /* domain has gcr3 table */
+#define PD_GIOV_MASK		(1UL << 4) /* domain enable GIOV support */
 
 extern bool amd_iommu_dump;
 #define DUMP_printk(format, arg...)				\

drivers/iommu/amd/init.c

@@ -2068,6 +2068,17 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 
 	init_iommu_perf_ctr(iommu);
 
+	if (amd_iommu_pgtable == AMD_IOMMU_V2) {
+		if (!iommu_feature(iommu, FEATURE_GIOSUP) ||
+		    !iommu_feature(iommu, FEATURE_GT)) {
+			pr_warn("Cannot enable v2 page table for DMA-API. Fallback to v1.\n");
+			amd_iommu_pgtable = AMD_IOMMU_V1;
+		} else if (iommu_default_passthrough()) {
+			pr_warn("V2 page table doesn't support passthrough mode. Fallback to v1.\n");
+			amd_iommu_pgtable = AMD_IOMMU_V1;
+		}
+	}
+
 	if (is_rd890_iommu(iommu->dev)) {
 		int i, j;
 
@@ -2146,6 +2157,8 @@ static void print_iommu_info(void)
 		if (amd_iommu_xt_mode == IRQ_REMAP_X2APIC_MODE)
 			pr_info("X2APIC enabled\n");
 	}
+	if (amd_iommu_pgtable == AMD_IOMMU_V2)
+		pr_info("V2 page table enabled\n");
 }
 
 static int __init amd_iommu_init_pci(void)

drivers/iommu/amd/iommu.c

@@ -1597,6 +1597,9 @@ static void set_dte_entry(struct amd_iommu *iommu, u16 devid,
 
 		tmp = DTE_GCR3_VAL_C(gcr3) << DTE_GCR3_SHIFT_C;
 		flags    |= tmp;
+
+		if (domain->flags & PD_GIOV_MASK)
+			pte_root |= DTE_FLAG_GIOV;
 	}
 
 	flags &= ~DEV_DOMID_MASK;