pseries: Restructure class_options functions

Currently each of the *_class_options() functions for the pseries-2.1 ..
pseries-2.5 machine types are standalone.  This will become harder to
maintain as new versions are added.

This patch restructures them similarly to x86 where each function calls
the one from the next version, then overrides anything necessary for
compatibility with the specific version and older.

The default behaviour - that for the most recent machine are set up in
the base class initializer spapr_machine_class_init().  Previously it had
some things set up to default to older behaviour with the more recent
machines overriding it.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: NAlexey Kardashevskiy <aik@ozlabs.ru>

hw/ppc/spapr.c

@@ -2266,6 +2266,12 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
 
     mc->desc = "pSeries Logical Partition (PAPR compliant)";
+
+    /*
+     * We set up the default / latest behaviour here.  The class_init
+     * functions for the specific versioned machine types can override
+     * these details for backwards compatibility
+     */
     mc->init = ppc_spapr_init;
     mc->reset = ppc_spapr_reset;
     mc->block_default_type = IF_SCSI;
@@ -2281,7 +2287,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     hc->unplug = spapr_machine_device_unplug;
     mc->cpu_index_to_socket_id = spapr_cpu_index_to_socket_id;
 
-    smc->dr_lmb_enabled = false;
+    smc->dr_lmb_enabled = true;
     fwc->get_dev_path = spapr_get_fw_dev_path;
     nc->nmi_monitor_handler = spapr_nmi;
 }
@@ -2335,11 +2341,9 @@ static void spapr_machine_2_5_instance_options(MachineState *machine)
 
 static void spapr_machine_2_5_class_options(MachineClass *mc)
 {
-    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
-
+    /* Defaults for the latest behaviour inherited from the base class */
     mc->alias = "pseries";
     mc->is_default = 1;
-    smc->dr_lmb_enabled = true;
 }
 
 DEFINE_SPAPR_MACHINE(2_5, "2.5");
@@ -2357,6 +2361,12 @@ static void spapr_machine_2_4_instance_options(MachineState *machine)
 
 static void spapr_machine_2_4_class_options(MachineClass *mc)
 {
+    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
+
+    spapr_machine_2_5_class_options(mc);
+    mc->alias = NULL;
+    mc->is_default = 0;
+    smc->dr_lmb_enabled = false;
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_4);
 }
 
@@ -2383,6 +2393,7 @@ static void spapr_machine_2_3_instance_options(MachineState *machine)
 
 static void spapr_machine_2_3_class_options(MachineClass *mc)
 {
+    spapr_machine_2_4_class_options(mc);
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_3);
 }
 DEFINE_SPAPR_MACHINE(2_3, "2.3");
@@ -2407,6 +2418,7 @@ static void spapr_machine_2_2_instance_options(MachineState *machine)
 
 static void spapr_machine_2_2_class_options(MachineClass *mc)
 {
+    spapr_machine_2_3_class_options(mc);
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_2);
 }
 DEFINE_SPAPR_MACHINE(2_2, "2.2");
@@ -2425,6 +2437,7 @@ static void spapr_machine_2_1_instance_options(MachineState *machine)
 
 static void spapr_machine_2_1_class_options(MachineClass *mc)
 {
+    spapr_machine_2_2_class_options(mc);
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_1);
 }
 DEFINE_SPAPR_MACHINE(2_1, "2.1");