[Qemu-ppc] [PATCH] spapr: Don't support query-hotpluggable-cpus on earlier pseries machine types

[David Gibson]

On Power, support for vCPU hotplug is new in qemu 2.7.  However, we
currently implement the query_hotpluggable_cpus hook the same for all
pseries machine type versions.

However, the old-style CPU initialization doesn't work with the new query
code, meaning that attempting to use query-hotpluggable-cpus on a
pseries-2.6 or earlier VM will cause qemu to SEGV.

This fixes the problem by simply disabling the hook for earlier machine
types.

Signed-off-by: David Gibson <address@hidden>
---
 hw/ppc/spapr.c | 1 +
 1 file changed, 1 insertion(+)

This is a bugfix, so once I have a review from someone, I intend send
a pull request for qemu-2.7.

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index fbbd051..4746a60 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2521,6 +2521,7 @@ static void spapr_machine_2_6_class_options(MachineClass 
*mc)
     spapr_machine_2_7_class_options(mc);
     smc->dr_cpu_enabled = false;
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_6);
+    mc->query_hotpluggable_cpus = NULL; /* No vCPU hotplug on 2.6 and earlier 
*/
 }
 
 DEFINE_SPAPR_MACHINE(2_6, "2.6", false);
-- 
2.7.4