diff --git a/kvm-all.c b/kvm-all.c
index 91d3cbd43e..1a02076bfd 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -21,6 +21,7 @@
 #include <linux/kvm.h>
 
 #include "qemu-common.h"
+#include "qemu-barrier.h"
 #include "sysemu.h"
 #include "hw/hw.h"
 #include "gdbstub.h"
@@ -730,7 +731,7 @@ void kvm_flush_coalesced_mmio_buffer(void)
             ent = &ring->coalesced_mmio[ring->first];
 
             cpu_physical_memory_write(ent->phys_addr, ent->data, ent->len);
-            /* FIXME smp_wmb() */
+            smp_wmb();
             ring->first = (ring->first + 1) % KVM_COALESCED_MMIO_MAX;
         }
     }
diff --git a/qemu-barrier.h b/qemu-barrier.h
new file mode 100644
index 0000000000..3bd1075d66
--- /dev/null
+++ b/qemu-barrier.h
@@ -0,0 +1,7 @@
+#ifndef __QEMU_BARRIER_H
+#define __QEMU_BARRIER_H 1
+
+/* FIXME: arch dependant, x86 version */
+#define smp_wmb()   asm volatile("" ::: "memory")
+
+#endif