Commit c8721d35 authored by Bharata B Rao's avatar Bharata B Rao Committed by David Gibson
Browse files

spapr: Error out when CPU hotplug is attempted on older pseries machines 



CPU hotplug and coldplug aren't supported prior to pseries-2.7.  Further,
earlier machine types don't use CPU core objects at all.  These mean that
query-hotpluggable-cpus and coldplug on older pseries machines will crash
QEMU.  It also means that hotpluggable_cpus flag in query-machines will
be incorrectly set to true for pseries < 2.7, since it is based on the
presence of the query_hotpluggable_cpus hook.

- Don't assign the query_hotpluggable_cpus hook for pseries < 2.7
- query_hotpluggable_cpus should therefore never be called on pseries <
  2.7, so add an assert
- spapr_core_pre_plug() should fail hot/cold plug attempts for pseries <
  2.7, since core objects are never used there
- spapr_core_plug() should therefore never be called for pseries < 2.7, so
  add an assert.

Signed-off-by: default avatarBharata B Rao <bharata@linux.vnet.ibm.com>
[dwg: Change from query_hotpluggable_cpus returning NULL for pseries < 2.7
 to not being called at all, reword commit message for accuracy]
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 8b54a6a6

hw/ppc/spapr.c

+6 −1
Original line number Diff line number Diff line
@@ -2376,8 +2376,11 @@ static HotpluggableCPUList *spapr_query_hotpluggable_cpus(MachineState *machine) 
    int i;

    HotpluggableCPUList *head = NULL;

    sPAPRMachineState *spapr = SPAPR_MACHINE(machine);

    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(machine);

    int spapr_max_cores = max_cpus / smp_threads;



    g_assert(smc->dr_cpu_enabled);



    for (i = 0; i < spapr_max_cores; i++) {

        HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1);

        HotpluggableCPU *cpu_item = g_new0(typeof(*cpu_item), 1);
@@ -2432,7 +2435,9 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data) 
    hc->plug = spapr_machine_device_plug;

    hc->unplug = spapr_machine_device_unplug;

    mc->cpu_index_to_socket_id = spapr_cpu_index_to_socket_id;

    if (smc->dr_cpu_enabled) {

        mc->query_hotpluggable_cpus = spapr_query_hotpluggable_cpus;

    }



    smc->dr_lmb_enabled = true;

    smc->dr_cpu_enabled = true;

hw/ppc/spapr_cpu_core.c

+6 −13
Original line number Diff line number Diff line
@@ -166,18 +166,11 @@ 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);



    if (!smc->dr_cpu_enabled) {

        /*

         * This is a cold plugged CPU core but the machine doesn't support

         * DR. So skip the hotplug path ensuring that the core is brought

         * up online with out an associated DR connector.

         */

        return;

    }



    g_assert(drc);



    /*
@@ -225,13 +218,13 @@ 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 (strcmp(base_core_type, type)) {

        error_setg(&local_err, "CPU core type should be %s", base_core_type);

    if (!smc->dr_cpu_enabled) {

        error_setg(&local_err, "CPU hotplug not supported for this machine");

        goto out;

    }



    if (!smc->dr_cpu_enabled && dev->hotplugged) {

        error_setg(&local_err, "CPU hotplug not supported for this machine");

    if (strcmp(base_core_type, type)) {

        error_setg(&local_err, "CPU core type should be %s", base_core_type);

        goto out;

    }