[Qemu-devel] [RFC PATCH v0 5/5] spapr: Prefer arch_id over cpu_index

[Bharata B Rao <bharata@linux.vnet.ibm.com>]

Starting from pseries-2.7, prefer the use of arch_id (cpu_dt_id) over
cpu_index for cpu vmstate registration and in XICS code.

This allows migration to work when CPU cores are not necessarily
unplugged in LIFO order.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr.c          | 2 ++
 hw/ppc/spapr_cpu_core.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 7f33a1b..caa6254 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -2426,6 +2426,7 @@ 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;
     mc->query_hotpluggable_cpus = spapr_query_hotpluggable_cpus;
+    mc->prefer_arch_id_over_cpu_index = true;
 
     smc->dr_lmb_enabled = true;
     smc->dr_cpu_enabled = true;
@@ -2512,6 +2513,7 @@ static void spapr_machine_2_6_class_options(MachineClass *mc)
     sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
 
     spapr_machine_2_7_class_options(mc);
+    mc->prefer_arch_id_over_cpu_index = false;
     smc->dr_cpu_enabled = false;
     SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_2_6);
 }
diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 70b6b0b..4bfd01e 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -281,6 +281,8 @@ static void spapr_cpu_core_realize_child(Object *child, Error **errp)
 
 static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
 {
+    MachineState *machine = MACHINE(qdev_get_machine());
+    MachineClass *mc = MACHINE_GET_CLASS(machine);
     sPAPRCPUCore *sc = SPAPR_CPU_CORE(OBJECT(dev));
     CPUCore *cc = CPU_CORE(OBJECT(dev));
     const char *typename = object_class_get_name(sc->cpu_class);
@@ -295,6 +297,9 @@ static void spapr_cpu_core_realize(DeviceState *dev, Error **errp)
         obj = sc->threads + i * size;
 
         object_initialize(obj, size, typename);
+        if (mc->prefer_arch_id_over_cpu_index) {
+            CPU(obj)->prefer_arch_id_over_cpu_index = true;
+        }
         snprintf(id, sizeof(id), "thread[%d]", i);
         object_property_add_child(OBJECT(sc), id, obj, &local_err);
         if (local_err) {
-- 
2.7.4