iommu/amd: Move Stoney Ridge check to detect_ivrs()

The AMD IOMMU will not be enabled on AMD Stoney Ridge systems. Bail
out even earlier and refuse to even detect the IOMMU there.

References: https://bugzilla.kernel.org/show_bug.cgi?id=212133
References: https://bugzilla.suse.com/show_bug.cgi?id=1183132
Cc: stable@vger.kernel.org # v5.11
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Link: https://lore.kernel.org/r/20210317091037.31374-2-joro@8bytes.orgAcked-by: Huang Rui <ray.huang@amd.com>

drivers/iommu/amd/init.c

@@ -2714,7 +2714,6 @@ static int __init early_amd_iommu_init(void)
 	struct acpi_table_header *ivrs_base;
 	int i, remap_cache_sz, ret;
 	acpi_status status;
-	u32 pci_id;
 
 	if (!amd_iommu_detected)
 		return -ENODEV;
@@ -2804,16 +2803,6 @@ static int __init early_amd_iommu_init(void)
 	if (ret)
 		goto out;
 
-	/* Disable IOMMU if there's Stoney Ridge graphics */
-	for (i = 0; i < 32; i++) {
-		pci_id = read_pci_config(0, i, 0, 0);
-		if ((pci_id & 0xffff) == 0x1002 && (pci_id >> 16) == 0x98e4) {
-			pr_info("Disable IOMMU on Stoney Ridge\n");
-			amd_iommu_disabled = true;
-			break;
-		}
-	}
-
 	/* Disable any previously enabled IOMMUs */
 	if (!is_kdump_kernel() || amd_iommu_disabled)
 		disable_iommus();
@@ -2880,6 +2869,7 @@ static bool detect_ivrs(void)
 {
 	struct acpi_table_header *ivrs_base;
 	acpi_status status;
+	int i;
 
 	status = acpi_get_table("IVRS", 0, &ivrs_base);
 	if (status == AE_NOT_FOUND)
@@ -2892,6 +2882,17 @@ static bool detect_ivrs(void)
 
 	acpi_put_table(ivrs_base);
 
+	/* Don't use IOMMU if there is Stoney Ridge graphics */
+	for (i = 0; i < 32; i++) {
+		u32 pci_id;
+
+		pci_id = read_pci_config(0, i, 0, 0);
+		if ((pci_id & 0xffff) == 0x1002 && (pci_id >> 16) == 0x98e4) {
+			pr_info("Disable IOMMU on Stoney Ridge\n");
+			return false;
+		}
+	}
+
 	/* Make sure ACS will be enabled during PCI probe */
 	pci_request_acs();