spapr: Correctly set query_hotpluggable_cpus hook based on machine version

Prior to c8721d3 "spapr: Error out when CPU hotplug is attempted on older
pseries machines", attempting to use query-hotpluggable-cpus on pseries-2.6
and earlier machine types would SEGV.

That change fixed that, but due to some unexpected interactions in init
order and a brown-paper-bag worthy failure to test, it accidentally
disabled query-hotpluggable-cpus for all pseries machine types, including
the current one which should allow it.

In fact, query_hotpluggable_cpus needs to be non-NULL when and only when
the dr_cpu_enabled flag in sPAPRMachineClass is set, which makes
dr_cpu_enabled itself redundant.

This patch removes dr_cpu_enabled, instead directly setting
query_hotpluggable_cpus from the machine class_init functions, and using
that to determine the availability of CPU hotplug when necessary.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 2 insertions, 5 deletions

diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 170ed154a6..704803ac23 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -153,7 +153,6 @@ void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
 void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
                      Error **errp)
 {
-    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(OBJECT(hotplug_dev));
     sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
     sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev));
     CPUCore *cc = CPU_CORE(dev);
@@ -166,8 +165,6 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
     int index = cc->core_id / smp_threads;
     int smt = kvmppc_smt_threads();
 
-    g_assert(smc->dr_cpu_enabled);
-
     drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);
     spapr->cores[index] = OBJECT(dev);
 
@@ -209,7 +206,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
                          Error **errp)
 {
     MachineState *machine = MACHINE(OBJECT(hotplug_dev));
-    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(OBJECT(hotplug_dev));
+    MachineClass *mc = MACHINE_GET_CLASS(hotplug_dev);
     sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
     int spapr_max_cores = max_cpus / smp_threads;
     int index;
@@ -218,7 +215,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
     char *base_core_type = spapr_get_cpu_core_type(machine->cpu_model);
     const char *type = object_get_typename(OBJECT(dev));
 
-    if (!smc->dr_cpu_enabled) {
+    if (!mc->query_hotpluggable_cpus) {
         error_setg(&local_err, "CPU hotplug not supported for this machine");
         goto out;
     }