diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index b321722f0e..d708ef5f00 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -8025,7 +8025,7 @@ qemuDomainAgentAvailable(virDomainObjPtr vm,
 
 
 static unsigned long long
-qemuDomainGetMemorySizeAlignment(virDomainDefPtr def)
+qemuDomainGetMemorySizeAlignment(const virDomainDef *def)
 {
     /* PPC requires the memory sizes to be rounded to 256MiB increments, so
      * round them to the size always. */