ppc/xics: rework the ICS classes inheritance tree

With the previous changes, we can now let the ICS_KVM class inherit
directly from ICS_BASE class and not from the intermediate ICS_SIMPLE.
It makes the class hierarchy much cleaner.

What is left in the top classes is the low level interface to access
the KVM XICS device in ICS_KVM and the XICS emulating handlers in
ICS_SIMPLE.

This should not break migration compatibility.
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/intc/xics_kvm.c

@@ -359,12 +359,10 @@ static void ics_kvm_class_init(ObjectClass *klass, void *data)
     ICSStateClass *icsc = ICS_BASE_CLASS(klass);
     DeviceClass *dc = DEVICE_CLASS(klass);
 
-    /*
-     * Use device_class_set_parent_realize() when ics-kvm inherits
-     * directly from ics-base and not from ics-simple anymore.
-     */
-    dc->realize = ics_kvm_realize;
-    dc->reset = ics_kvm_reset;
+    device_class_set_parent_realize(dc, ics_kvm_realize,
+                                    &icsc->parent_realize);
+    device_class_set_parent_reset(dc, ics_kvm_reset,
+                                  &icsc->parent_reset);
 
     icsc->pre_save = ics_get_kvm_state;
     icsc->post_load = ics_set_kvm_state;
@@ -373,7 +371,7 @@ static void ics_kvm_class_init(ObjectClass *klass, void *data)
 
 static const TypeInfo ics_kvm_info = {
     .name = TYPE_ICS_KVM,
-    .parent = TYPE_ICS_SIMPLE,
+    .parent = TYPE_ICS_BASE,
     .instance_size = sizeof(ICSState),
     .class_init = ics_kvm_class_init,
 };

hw/ppc/spapr.c

@@ -137,7 +137,7 @@ static ICSState *spapr_ics_create(sPAPRMachineState *spapr,
         goto error;
     }
 
-    return ICS_SIMPLE(obj);
+    return ICS_BASE(obj);
 
 error:
     error_propagate(errp, local_err);