s390/sclp: rework sclp event facility initialization + device realization

The current code only works by chance. The event facility is a sysbus
device, but specifies in its class structure as parent the DeviceClass
(instead of a device class).

The init function in return lies therefore at the same position as
the init function of SysBusDeviceClass and gets triggered instead -
a very bad idea of doing that (e.g. the parameter types don't match).

Let's bring the initialization code up to date, initializing the event
facility + child events in .instance_init and moving the realization of
the child events out of the init call, into the realization step.

Device realization is now automatically performed when the event facility
itself is realized. That realization implicitly triggers realization of
the child bus, which in turn initializes the events.

Please note that we have to manually propagate the realization of the bus
children, common code still has a TODO set for that task.

Reviewed-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

hw/s390x/event-facility.c

@@ -27,12 +27,12 @@ typedef struct SCLPEventsBus {
 struct SCLPEventFacility {
     SysBusDevice parent_obj;
     SCLPEventsBus sbus;
+    SCLPEvent quiesce_event;
+    SCLPEvent cpu_hotplug_event;
     /* guest' receive mask */
     unsigned int receive_mask;
 };
 
-static SCLPEvent cpu_hotplug;
-
 /* return true if any child has event pending set */
 static bool event_pending(SCLPEventFacility *ef)
 {
@@ -287,8 +287,26 @@ out:
 
 #define TYPE_SCLP_EVENTS_BUS "s390-sclp-events-bus"
 
+static void sclp_events_bus_realize(BusState *bus, Error **errp)
+{
+    BusChild *kid;
+
+    /* TODO: recursive realization has to be done in common code */
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        DeviceState *dev = kid->child;
+
+        object_property_set_bool(OBJECT(dev), true, "realized", errp);
+        if (*errp) {
+            return;
+        }
+    }
+}
+
 static void sclp_events_bus_class_init(ObjectClass *klass, void *data)
 {
+    BusClass *bc = BUS_CLASS(klass);
+
+    bc->realize = sclp_events_bus_realize;
 }
 
 static const TypeInfo sclp_events_bus_info = {
@@ -325,26 +343,24 @@ static const VMStateDescription vmstate_event_facility = {
      }
 };
 
-static int init_event_facility(SCLPEventFacility *event_facility)
+static void init_event_facility(Object *obj)
 {
-    DeviceState *sdev = DEVICE(event_facility);
-    DeviceState *quiesce;
+    SCLPEventFacility *event_facility = EVENT_FACILITY(obj);
+    DeviceState *sdev = DEVICE(obj);
 
     /* Spawn a new bus for SCLP events */
     qbus_create_inplace(&event_facility->sbus, sizeof(event_facility->sbus),
                         TYPE_SCLP_EVENTS_BUS, sdev, NULL);
 
-    quiesce = qdev_create(&event_facility->sbus.qbus, "sclpquiesce");
-    if (!quiesce) {
-        return -1;
-    }
-    qdev_init_nofail(quiesce);
-
-    object_initialize(&cpu_hotplug, sizeof(cpu_hotplug), TYPE_SCLP_CPU_HOTPLUG);
-    qdev_set_parent_bus(DEVICE(&cpu_hotplug), BUS(&event_facility->sbus));
-    object_property_set_bool(OBJECT(&cpu_hotplug), true, "realized", NULL);
-
-    return 0;
+    object_initialize(&event_facility->quiesce_event, sizeof(SCLPEvent),
+                      "sclpquiesce");
+    qdev_set_parent_bus(DEVICE(&event_facility->quiesce_event),
+                        &event_facility->sbus.qbus);
+    object_initialize(&event_facility->cpu_hotplug_event, sizeof(SCLPEvent),
+                      TYPE_SCLP_CPU_HOTPLUG);
+    qdev_set_parent_bus(DEVICE(&event_facility->cpu_hotplug_event),
+                        &event_facility->sbus.qbus);
+    /* the facility will automatically realize the devices via the bus */
 }
 
 static void reset_event_facility(DeviceState *dev)
@@ -363,7 +379,6 @@ static void init_event_facility_class(ObjectClass *klass, void *data)
     dc->reset = reset_event_facility;
     dc->vmsd = &vmstate_event_facility;
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
-    k->init = init_event_facility;
     k->command_handler = command_handler;
     k->event_pending = event_pending;
 }
@@ -371,6 +386,7 @@ static void init_event_facility_class(ObjectClass *klass, void *data)
 static const TypeInfo sclp_event_facility_info = {
     .name          = TYPE_SCLP_EVENT_FACILITY,
     .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_init = init_event_facility,
     .instance_size = sizeof(SCLPEventFacility),
     .class_init    = init_event_facility_class,
     .class_size    = sizeof(SCLPEventFacilityClass),

include/hw/s390x/event-facility.h

@@ -191,8 +191,7 @@ typedef struct SCLPEventClass {
 typedef struct SCLPEventFacility SCLPEventFacility;
 
 typedef struct SCLPEventFacilityClass {
-    DeviceClass parent_class;
-    int (*init)(SCLPEventFacility *ef);
+    SysBusDeviceClass parent_class;
     void (*command_handler)(SCLPEventFacility *ef, SCCB *sccb, uint64_t code);
     bool (*event_pending)(SCLPEventFacility *ef);
 } SCLPEventFacilityClass;