[Qemu-devel] [PATCH v2 2/6] s390x/vfio: ap: Use the APdevice as a child of the APBus

[Pierre Morel]

Two good reasons to use the base device as a child of the
AP BUS:
- We can easily find the device without traversing the qtree.
- In case we have different APdevice instantiation, VFIO with
  interception or emulation, we will need the APDevice as
  a parent device.

Signed-off-by: Pierre Morel <pmo...@linux.ibm.com>
---
 hw/s390x/ap-device.c         | 22 ++++++++++++++++++++++
 hw/vfio/ap.c                 | 16 ++++++----------
 include/hw/s390x/ap-device.h |  2 ++
 3 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/hw/s390x/ap-device.c b/hw/s390x/ap-device.c
index f5ac8db..554d5aa 100644
--- a/hw/s390x/ap-device.c
+++ b/hw/s390x/ap-device.c
@@ -11,13 +11,35 @@
 #include "qemu/module.h"
 #include "qapi/error.h"
 #include "hw/qdev.h"
+#include "hw/s390x/ap-bridge.h"
 #include "hw/s390x/ap-device.h"
 
+APDevice *s390_get_ap(void)
+{
+    static DeviceState *apb;
+    BusState *bus;
+    BusChild *child;
+    static APDevice *ap;
+
+    if (ap) {
+        return ap;
+    }
+
+    apb = s390_get_ap_bridge();
+    /* We have only a single child on the BUS */
+    bus = qdev_get_child_bus(apb, TYPE_AP_BUS);
+    child = QTAILQ_FIRST(&bus->children);
+    assert(child != NULL);
+    ap = DO_UPCAST(APDevice, parent_obj, child->child);
+    return ap;
+}
+
 static void ap_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
     dc->desc = "AP device class";
+    dc->bus_type = TYPE_AP_BUS;
     dc->hotpluggable = false;
 }
 
diff --git a/hw/vfio/ap.c b/hw/vfio/ap.c
index 65de952..94e5a1a 100644
--- a/hw/vfio/ap.c
+++ b/hw/vfio/ap.c
@@ -35,9 +35,6 @@ typedef struct VFIOAPDevice {
     VFIODevice vdev;
 } VFIOAPDevice;
 
-#define VFIO_AP_DEVICE(obj) \
-        OBJECT_CHECK(VFIOAPDevice, (obj), VFIO_AP_DEVICE_TYPE)
-
 static void vfio_ap_compute_needs_reset(VFIODevice *vdev)
 {
     vdev->needs_reset = false;
@@ -90,8 +87,8 @@ static void vfio_ap_realize(DeviceState *dev, Error **errp)
     char *mdevid;
     Error *local_err = NULL;
     VFIOGroup *vfio_group;
-    APDevice *apdev = AP_DEVICE(dev);
-    VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
+    APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
+    VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);
 
     vfio_group = vfio_ap_get_group(vapdev, &local_err);
     if (!vfio_group) {
@@ -120,8 +117,8 @@ out_err:
 
 static void vfio_ap_unrealize(DeviceState *dev, Error **errp)
 {
-    APDevice *apdev = AP_DEVICE(dev);
-    VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
+    APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
+    VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);
     VFIOGroup *group = vapdev->vdev.group;
 
     vfio_ap_put_device(vapdev);
@@ -136,8 +133,8 @@ static Property vfio_ap_properties[] = {
 static void vfio_ap_reset(DeviceState *dev)
 {
     int ret;
-    APDevice *apdev = AP_DEVICE(dev);
-    VFIOAPDevice *vapdev = VFIO_AP_DEVICE(apdev);
+    APDevice *apdev = DO_UPCAST(APDevice, parent_obj, dev);
+    VFIOAPDevice *vapdev = DO_UPCAST(VFIOAPDevice, apdev, apdev);
 
     ret = ioctl(vapdev->vdev.fd, VFIO_DEVICE_RESET);
     if (ret) {
@@ -163,7 +160,6 @@ static void vfio_ap_class_init(ObjectClass *klass, void 
*data)
     dc->unrealize = vfio_ap_unrealize;
     dc->hotpluggable = false;
     dc->reset = vfio_ap_reset;
-    dc->bus_type = TYPE_AP_BUS;
 }
 
 static const TypeInfo vfio_ap_info = {
diff --git a/include/hw/s390x/ap-device.h b/include/hw/s390x/ap-device.h
index 765e908..5f3c840 100644
--- a/include/hw/s390x/ap-device.h
+++ b/include/hw/s390x/ap-device.h
@@ -19,4 +19,6 @@ typedef struct APDevice {
 #define AP_DEVICE(obj) \
     OBJECT_CHECK(APDevice, (obj), AP_DEVICE_TYPE)
 
+APDevice *s390_get_ap(void);
+
 #endif /* HW_S390X_AP_DEVICE_H */
-- 
2.7.4