diff --git a/hw/s390-virtio-bus.c b/hw/s390-virtio-bus.c
index bb49e39..d4a12f7 100644
--- a/hw/s390-virtio-bus.c
+++ b/hw/s390-virtio-bus.c
@@ -60,6 +60,9 @@ static const VirtIOBindings virtio_s390_bindings;
 
 static ram_addr_t s390_virtio_device_num_vq(VirtIOS390Device *dev);
 
+/* length of VirtIO device pages */
+const target_phys_addr_t virtio_size = S390_DEVICE_PAGES * TARGET_PAGE_SIZE;
+
 VirtIOS390Bus *s390_virtio_bus_init(ram_addr_t *ram_size)
 {
     VirtIOS390Bus *bus;
diff --git a/hw/s390-virtio-bus.h b/hw/s390-virtio-bus.h
index edf6d04..0c412d0 100644
--- a/hw/s390-virtio-bus.h
+++ b/hw/s390-virtio-bus.h
@@ -33,7 +33,7 @@
 #define VIRTIO_VQCONFIG_LEN		24
 
 #define VIRTIO_RING_LEN			(TARGET_PAGE_SIZE * 3)
-#define S390_DEVICE_PAGES		256
+#define S390_DEVICE_PAGES		512
 
 typedef struct VirtIOS390Device {
     DeviceState qdev;
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 79aa6c9..00939a3 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -310,6 +310,9 @@ static inline void kvm_s390_interrupt_internal(CPUState *env, int type,
 #endif
 CPUState *s390_cpu_addr2state(uint16_t cpu_addr);
 
+/* from s390-virtio-bus */
+extern const target_phys_addr_t virtio_size;
+
 #ifndef KVM_S390_SIGP_STOP
 #define KVM_S390_SIGP_STOP              0
 #define KVM_S390_PROGRAM_INT            0