[PATCH 2/3] s390x: add have_virtio_ccw

[Gerd Hoffmann <kraxel@redhat.com>]

Introduce a symbol which can be used to prevent ccw modules
being loaded into system emulators without ccw support.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/s390x/virtio-ccw.h | 5 +++++
 hw/s390x/virtio-ccw.c | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/hw/s390x/virtio-ccw.h b/hw/s390x/virtio-ccw.h
index 49a2b8ca42df..0168232e3b8d 100644
--- a/hw/s390x/virtio-ccw.h
+++ b/hw/s390x/virtio-ccw.h
@@ -63,6 +63,11 @@ typedef struct VirtioBusClass VirtioCcwBusClass;
 DECLARE_OBJ_CHECKERS(VirtioCcwBusState, VirtioCcwBusClass,
                      VIRTIO_CCW_BUS, TYPE_VIRTIO_CCW_BUS)
 
+/*
+ * modules can reference this symbol to avoid being loaded
+ * into system emulators without ccw support
+ */
+extern bool have_virtio_ccw;
 
 struct VirtIOCCWDeviceClass {
     CCWDeviceClass parent_class;
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 06c06056814b..314ed7b24566 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -35,6 +35,8 @@
 
 #define NR_CLASSIC_INDICATOR_BITS 64
 
+bool have_virtio_ccw = true;
+
 static int virtio_ccw_dev_post_load(void *opaque, int version_id)
 {
     VirtioCcwDevice *dev = VIRTIO_CCW_DEVICE(opaque);
-- 
2.30.2