diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 1dc3718..2883ac3 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -127,7 +127,8 @@ static inline int get_acpihid_device_id(struct device *dev,
 		return -ENODEV;
 
 	list_for_each_entry(p, &acpihid_map, list) {
-		if (acpi_dev_hid_uid_match(adev, p->hid, p->uid)) {
+		if (acpi_dev_hid_uid_match(adev, p->hid,
+					   p->uid[0] ? p->uid : NULL)) {
 			if (entry)
 				*entry = p;
 			return p->devid;
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 2b9a67e..5b81fd1 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1329,8 +1329,8 @@ static int __init init_iommu_from_acpi(struct amd_iommu *iommu,
 		}
 		case IVHD_DEV_ACPI_HID: {
 			u16 devid;
-			u8 hid[ACPIHID_HID_LEN] = {0};
-			u8 uid[ACPIHID_UID_LEN] = {0};
+			u8 hid[ACPIHID_HID_LEN];
+			u8 uid[ACPIHID_UID_LEN];
 			int ret;
 
 			if (h->type != 0x40) {
@@ -1347,6 +1347,7 @@ static int __init init_iommu_from_acpi(struct amd_iommu *iommu,
 				break;
 			}
 
+			uid[0] = '\0';
 			switch (e->uidf) {
 			case UID_NOT_PRESENT:
 
@@ -1361,8 +1362,8 @@ static int __init init_iommu_from_acpi(struct amd_iommu *iommu,
 				break;
 			case UID_IS_CHARACTER:
 
-				memcpy(uid, (u8 *)(&e->uid), ACPIHID_UID_LEN - 1);
-				uid[ACPIHID_UID_LEN - 1] = '\0';
+				memcpy(uid, &e->uid, e->uidl);
+				uid[e->uidl] = '\0';
 
 				break;
 			default:
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 7b37542..1faa08c 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -693,6 +693,15 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group,
 	return ret;
 }
 
+static bool iommu_is_attach_deferred(struct iommu_domain *domain,
+				     struct device *dev)
+{
+	if (domain->ops->is_attach_deferred)
+		return domain->ops->is_attach_deferred(domain, dev);
+
+	return false;
+}
+
 /**
  * iommu_group_add_device - add a device to an iommu group
  * @group: the group into which to add the device (reference should be held)
@@ -747,7 +756,7 @@ int iommu_group_add_device(struct iommu_group *group, struct device *dev)
 
 	mutex_lock(&group->mutex);
 	list_add_tail(&device->list, &group->devices);
-	if (group->domain)
+	if (group->domain  && !iommu_is_attach_deferred(group->domain, dev))
 		ret = __iommu_attach_device(group->domain, dev);
 	mutex_unlock(&group->mutex);
 	if (ret)
@@ -1653,9 +1662,6 @@ static int __iommu_attach_device(struct iommu_domain *domain,
 				 struct device *dev)
 {
 	int ret;
-	if ((domain->ops->is_attach_deferred != NULL) &&
-	    domain->ops->is_attach_deferred(domain, dev))
-		return 0;
 
 	if (unlikely(domain->ops->attach_dev == NULL))
 		return -ENODEV;
@@ -1727,8 +1733,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid);
 static void __iommu_detach_device(struct iommu_domain *domain,
 				  struct device *dev)
 {
-	if ((domain->ops->is_attach_deferred != NULL) &&
-	    domain->ops->is_attach_deferred(domain, dev))
+	if (iommu_is_attach_deferred(domain, dev))
 		return;
 
 	if (unlikely(domain->ops->detach_dev == NULL))