diff --git a/qemu-char.c b/qemu-char.c
index 18c42a3..800d6a6 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3115,7 +3115,7 @@
 
     backend->memory = g_new0(ChardevMemory, 1);
 
-    val = qemu_opt_get_number(opts, "size", 0);
+    val = qemu_opt_get_size(opts, "size", 0);
     if (val != 0) {
         backend->memory->has_size = true;
         backend->memory->size = val;