iommu/amd: Move V2 page table support check to early_amd_iommu_init()

amd_iommu_pgtable validation has to be done before calling
iommu_snp_enable(). It can be done immediately after reading IOMMU
features. Hence move this check to early_amd_iommu_init().

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20241028093810.5901-7-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: hegdevasant

drivers/iommu/amd/init.c

@@ -2070,13 +2070,6 @@ static int __init iommu_init_pci(struct amd_iommu *iommu)
 
 	init_iommu_perf_ctr(iommu);
 
-	if (amd_iommu_pgtable == AMD_IOMMU_V2) {
-		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;
-		}
-	}
-
 	if (is_rd890_iommu(iommu->dev)) {
 		int i, j;
 
@@ -3090,6 +3083,13 @@ static int __init early_amd_iommu_init(void)
 	    FIELD_GET(FEATURE_GATS, amd_iommu_efr) == GUEST_PGTABLE_5_LEVEL)
 		amd_iommu_gpt_level = PAGE_MODE_5_LEVEL;
 
+	if (amd_iommu_pgtable == AMD_IOMMU_V2) {
+		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;
+		}
+	}
+
 	/* Disable any previously enabled IOMMUs */
 	if (!is_kdump_kernel() || amd_iommu_disabled)
 		disable_iommus();