From: Michael Roth <mdroth@linux.vnet.ibm.com>

The 'dr_phb_enabled' field of that class can be set as part of
machine-specific init code. It will be used to conditionally
enable creation of DRC objects and device-tree description to
facilitate hotplug of PHBs.

Since we can't migrate this state to older machine types,
default the option to true and disable it for older machine
types.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/ppc/spapr.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index d94284f423be..2687b65798d7 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -4169,6 +4169,7 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     smc->default_caps.caps[SPAPR_CAP_NESTED_KVM_HV] = SPAPR_CAP_OFF;
     spapr_caps_add_properties(smc, &error_abort);
     smc->irq = &spapr_irq_xics;
+    smc->dr_phb_enabled = true;
 }
 
 static const TypeInfo spapr_machine_info = {
@@ -4234,6 +4235,7 @@ static void spapr_machine_3_1_class_options(MachineClass *mc)
     compat_props_add(mc->compat_props, hw_compat_3_1, hw_compat_3_1_len);
     mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("power8_v2.0");
     smc->update_dt_enabled = false;
+    smc->dr_phb_enabled = false;
 }
 
 DEFINE_SPAPR_MACHINE(3_1, "3.1", false);