diff --git a/hw/sparc/sun4m_iommu.c b/hw/sparc/sun4m_iommu.c
index eb40f93..06703b1 100644
--- a/hw/sparc/sun4m_iommu.c
+++ b/hw/sparc/sun4m_iommu.c
@@ -331,7 +331,7 @@
     .name = "iommu",
     .version_id = 2,
     .minimum_version_id = 2,
-    .fields = (VMStateField[]) {
+    .fields = (const VMStateField[]) {
         VMSTATE_UINT32_ARRAY(regs, IOMMUState, IOMMU_NREGS),
         VMSTATE_UINT64(iostart, IOMMUState),
         VMSTATE_END_OF_LIST()