iommu/amd: Make sure IOMMU interrupts are re-enabled on resume

commit 9ddd592a upstream.

Unfortunatly the interrupts for the event log and the
peripheral page-faults are only enabled at boot but not
re-enabled at resume. Fix that.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
[bwh: Backport to 3.0:
 - Drop change to PPR log which was added in 3.3
  - Source is under arch/x86/kernel]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/x86/kernel/amd_iommu_init.c

@@ -1031,8 +1031,9 @@ static int iommu_setup_msi(struct amd_iommu *iommu)
 {
 	int r;
 
-	if (pci_enable_msi(iommu->dev))
-		return 1;
+	r = pci_enable_msi(iommu->dev);
+	if (r)
+		return r;
 
 	r = request_threaded_irq(iommu->dev->irq,
 				 amd_iommu_int_handler,
@@ -1042,24 +1043,33 @@ static int iommu_setup_msi(struct amd_iommu *iommu)
 
 	if (r) {
 		pci_disable_msi(iommu->dev);
-		return 1;
+		return r;
 	}
 
 	iommu->int_enabled = true;
-	iommu_feature_enable(iommu, CONTROL_EVT_INT_EN);
 
 	return 0;
 }
 
 static int iommu_init_msi(struct amd_iommu *iommu)
 {
+	int ret;
+
 	if (iommu->int_enabled)
-		return 0;
+		goto enable_faults;
 
 	if (pci_find_capability(iommu->dev, PCI_CAP_ID_MSI))
-		return iommu_setup_msi(iommu);
+		ret = iommu_setup_msi(iommu);
+	else
+		ret = -ENODEV;
 
-	return 1;
+	if (ret)
+		return ret;
+
+enable_faults:
+	iommu_feature_enable(iommu, CONTROL_EVT_INT_EN);
+
+	return 0;
 }
 
 /****************************************************************************