diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 5d630d5d1b..d3ca6b2ec4 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1375,6 +1375,7 @@ virBitmapParseUnlimited;
 virBitmapSetAll;
 virBitmapSetBit;
 virBitmapSetBitExpand;
+virBitmapShrink;
 virBitmapSize;
 virBitmapSubtract;
 virBitmapToData;
diff --git a/src/util/virbitmap.c b/src/util/virbitmap.c
index 7338f0255a..b2c5c7a6a5 100644
--- a/src/util/virbitmap.c
+++ b/src/util/virbitmap.c
@@ -1196,3 +1196,26 @@ virBitmapSubtract(virBitmapPtr a,
     for (i = 0; i < max; i++)
         a->map[i] &= ~b->map[i];
 }
+
+
+/**
+ * virBitmapShrink:
+ * @map: Pointer to bitmap
+ * @b: last bit position to be excluded from bitmap
+ *
+ * Resizes the bitmap so that no more than @b bits will fit into it.  Nothing
+ * will change if the size is already smaller than @b.
+ *
+ * NB: Does not adjust the map->map_len so that a subsequent virBitmapExpand
+ * doesn't necessarily need to reallocate.
+ */
+void
+virBitmapShrink(virBitmapPtr map,
+                size_t b)
+{
+    if (!map)
+        return;
+
+    if (map->max_bit >= b)
+        map->max_bit = b;
+}
diff --git a/src/util/virbitmap.h b/src/util/virbitmap.h
index 7b2bea8b53..2464814055 100644
--- a/src/util/virbitmap.h
+++ b/src/util/virbitmap.h
@@ -153,4 +153,6 @@ void virBitmapIntersect(virBitmapPtr a, virBitmapPtr b)
 void virBitmapSubtract(virBitmapPtr a, virBitmapPtr b)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
 
+void virBitmapShrink(virBitmapPtr map, size_t b);
+
 #endif