diff --git a/src/xenconfig/xen_xl.c b/src/xenconfig/xen_xl.c
index 05146d7db4e375597eace3018cf7784c8b7b18e6..984024bbafb57e5a1582cd3ccc7c29b1c14450dc 100644
--- a/src/xenconfig/xen_xl.c
+++ b/src/xenconfig/xen_xl.c
@@ -1261,11 +1261,11 @@ xenFormatXLVnuma(virConfValuePtr list,
     numaVnode->list = NULL;
 
     /* pnode */
-    virBufferAsprintf(&buf, "pnode=%ld", node);
+    virBufferAsprintf(&buf, "pnode=%zu", node);
     xenFormatXLVnode(numaVnode, &buf);
 
     /* size */
-    virBufferAsprintf(&buf, "size=%ld", nodeSize);
+    virBufferAsprintf(&buf, "size=%zu", nodeSize);
     xenFormatXLVnode(numaVnode, &buf);
 
     /* vcpus */