[Qemu-devel] [PULL 12/40] s390x: add helper get_machine_class

[Christian Borntraeger <borntraeger@de.ibm.com>]

From: Halil Pasic <pasic@linux.vnet.ibm.com>

We will need the machine class at machine initialization time, so the
usual way via qdev won't do. Let's cache the machine class and also use
the default values of the base machine for capability discovery.

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Message-Id: <20170711145441.33925-2-pasic@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c | 46 +++++++++++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 23 deletions(-)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 0c8f758..df2b055 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -255,36 +255,35 @@ static inline void machine_set_dea_key_wrap(Object *obj, bool value,
     ms->dea_key_wrap = value;
 }
 
+static S390CcwMachineClass *current_mc;
+
+static S390CcwMachineClass *get_machine_class(void)
+{
+    if (unlikely(!current_mc)) {
+        /*
+        * No s390 ccw machine was instantiated, we are likely to
+        * be called for the 'none' machine. The properties will
+        * have their after-initialization values.
+        */
+        current_mc = S390_MACHINE_CLASS(
+                     object_class_by_name(TYPE_S390_CCW_MACHINE));
+    }
+    return current_mc;
+}
+
 bool ri_allowed(void)
 {
-    if (kvm_enabled()) {
-        MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
-        if (object_class_dynamic_cast(OBJECT_CLASS(mc),
-                                      TYPE_S390_CCW_MACHINE)) {
-            S390CcwMachineClass *s390mc = S390_MACHINE_CLASS(mc);
-
-            return s390mc->ri_allowed;
-        }
-        /*
-         * Make sure the "none" machine can have ri, otherwise it won't * be
-         * unlocked in KVM and therefore the host CPU model might be wrong.
-         */
-        return true;
+    if (!kvm_enabled()) {
+        return false;
     }
-    return 0;
+    /* for "none" machine this results in true */
+    return get_machine_class()->ri_allowed;
 }
 
 bool cpu_model_allowed(void)
 {
-    MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
-    if (object_class_dynamic_cast(OBJECT_CLASS(mc),
-                                  TYPE_S390_CCW_MACHINE)) {
-        S390CcwMachineClass *s390mc = S390_MACHINE_CLASS(mc);
-
-        return s390mc->cpu_model_allowed;
-    }
-    /* allow CPU model qmp queries with the "none" machine */
-    return true;
+    /* for "none" machine this results in true */
+    return get_machine_class()->cpu_model_allowed;
 }
 
 static char *machine_get_loadparm(Object *obj, Error **errp)
@@ -394,6 +393,7 @@ static const TypeInfo ccw_machine_info = {
     static void ccw_machine_##suffix##_instance_init(Object *obj)             \
     {                                                                         \
         MachineState *machine = MACHINE(obj);                                 \
+        current_mc = S390_MACHINE_CLASS(MACHINE_GET_CLASS(machine));          \
         ccw_machine_##suffix##_instance_options(machine);                     \
     }                                                                         \
     static const TypeInfo ccw_machine_##suffix##_info = {                     \
-- 
2.7.4