Index: sys/dev/iommu/iommu_gas.c
===================================================================
--- sys/dev/iommu/iommu_gas.c
+++ sys/dev/iommu/iommu_gas.c
@@ -398,21 +398,12 @@
 	 * requirements, or violates lowaddr address requirement.
 	 */
 	entry = first;
-	while (entry != NULL) {
-		if ((first = RB_LEFT(entry, rb_entry)) != NULL) {
-			if (first->last >= a->common->lowaddr) {
-				/* All remaining ranges >= lowaddr */
-				break;
-			}
-			if (iommu_gas_match_one(a, first->last, entry->start,
-			    a->common->lowaddr)) {
-				iommu_gas_match_insert(a);
-				return (0);
-			}
-		}
-		if (entry->end >= a->common->lowaddr) {
-			/* All remaining ranges >= lowaddr */
-			break;
+	while (entry != NULL && entry->end < a->common->lowaddr) {
+		if ((first = RB_LEFT(entry, rb_entry)) != NULL &&
+		    iommu_gas_match_one(a, first->last, entry->start,
+		    a->common->lowaddr)) {
+			iommu_gas_match_insert(a);
+			return (0);
 		}
 		if ((first = RB_RIGHT(entry, rb_entry)) != NULL &&
 		    iommu_gas_match_one(a, entry->end, first->first,
@@ -435,6 +426,16 @@
 			entry = first;
 		}
 	}
+	if (entry == NULL)
+		return (ENOMEM);
+
+	if ((first = RB_LEFT(entry, rb_entry)) != NULL &&
+	    first->last < a->common->lowaddr &&
+	    iommu_gas_match_one(a, first->last, entry->start,
+	    a->common->lowaddr)) {
+		iommu_gas_match_insert(a);
+		return (0);
+	}
 	return (ENOMEM);
 }