diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index d12968c07c25..5a53fc920c58 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -2933,6 +2933,30 @@ resource_list_busy(struct resource_list *rl, int type, int rid)
 	return (1);
 }
 
+/**
+ * @brief Determine if a resource entry is reserved.
+ *
+ * Returns true if a resource entry is reserved meaning that it has an
+ * associated "reserved" resource.  The resource can either be
+ * allocated or unallocated.
+ *
+ * @param rl		the resource list to search
+ * @param type		the resource entry type (e.g. SYS_RES_MEMORY)
+ * @param rid		the resource identifier
+ *
+ * @returns Non-zero if the entry is reserved, zero otherwise.
+ */
+int
+resource_list_reserved(struct resource_list *rl, int type, int rid)
+{
+	struct resource_list_entry *rle;
+
+	rle = resource_list_find(rl, type, rid);
+	if (rle != NULL && rle->flags & RLE_RESERVED)
+		return (1);
+	return (0);
+}
+
 /**
  * @brief Find a resource entry by type and rid.
  *
diff --git a/sys/sys/bus.h b/sys/sys/bus.h
index 88a0f60cd7e3..ec3be645f79e 100644
--- a/sys/sys/bus.h
+++ b/sys/sys/bus.h
@@ -256,6 +256,7 @@ int	resource_list_add_next(struct resource_list *rl,
 			  u_long start, u_long end, u_long count);
 int	resource_list_busy(struct resource_list *rl,
 			   int type, int rid);
+int	resource_list_reserved(struct resource_list *rl, int type, int rid);
 struct resource_list_entry*
 	resource_list_find(struct resource_list *rl,
 			   int type, int rid);