Commit 12bf2d33 authored by Greg Kurz's avatar Greg Kurz Committed by David Gibson
Browse files

spapr: disintricate core-id from DT semantics 



The goal of this patch is to have a stable core-id which does not depend
on any DT related semantics, which involve non-obvious computations on
modern PowerPC server cpus.

With this patch, the DT core id is computed on-demand as:

       (core-id / smp_threads) * smt

where smt is the number of threads per core in the host.

This formula should be consolidated in a helper since it is needed in
several places.

Other uses for core-id includes: compute a stable cpu_index (which
allows random order hotplug/unplug without breaking migration) and
NUMA.

Signed-off-by: default avatarGreg Kurz <groug@kaod.org>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent 2fff4bad

hw/ppc/spapr.c

+5 −5
Original line number Diff line number Diff line
@@ -1815,10 +1815,11 @@ static void ppc_spapr_init(MachineState *machine) 


        spapr->cores = g_new0(Object *, spapr_max_cores);

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

            int core_dt_id = i * smt;

            int core_id = i * smp_threads;

            sPAPRDRConnector *drc =

                spapr_dr_connector_new(OBJECT(spapr),

                                       SPAPR_DR_CONNECTOR_TYPE_CPU, core_dt_id);

                                       SPAPR_DR_CONNECTOR_TYPE_CPU,

                                       (core_id / smp_threads) * smt);



            qemu_register_reset(spapr_drc_reset, drc);
@@ -1834,7 +1835,7 @@ static void ppc_spapr_init(MachineState *machine) 
                core  = object_new(type);

                object_property_set_int(core, smp_threads, "nr-threads",

                                        &error_fatal);

                object_property_set_int(core, core_dt_id, CPU_CORE_PROP_CORE_ID,

                object_property_set_int(core, core_id, CPU_CORE_PROP_CORE_ID,

                                        &error_fatal);

                object_property_set_bool(core, true, "realized", &error_fatal);

            }
@@ -2376,7 +2377,6 @@ static HotpluggableCPUList *spapr_query_hotpluggable_cpus(MachineState *machine) 
    HotpluggableCPUList *head = NULL;

    sPAPRMachineState *spapr = SPAPR_MACHINE(machine);

    int spapr_max_cores = max_cpus / smp_threads;

    int smt = kvmppc_smt_threads();



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

        HotpluggableCPUList *list_item = g_new0(typeof(*list_item), 1);
@@ -2386,7 +2386,7 @@ static HotpluggableCPUList *spapr_query_hotpluggable_cpus(MachineState *machine) 
        cpu_item->type = spapr_get_cpu_core_type(machine->cpu_model);

        cpu_item->vcpus_count = smp_threads;

        cpu_props->has_core_id = true;

        cpu_props->core_id = i * smt;

        cpu_props->core_id = i * smp_threads;

        /* TODO: add 'has_node/node' here to describe

           to which node core belongs */

hw/ppc/spapr_cpu_core.c

+11 −13
Original line number Diff line number Diff line
@@ -103,7 +103,6 @@ static void spapr_core_release(DeviceState *dev, void *opaque) 
    size_t size = object_type_get_instance_size(typename);

    sPAPRMachineState *spapr = SPAPR_MACHINE(qdev_get_machine());

    CPUCore *cc = CPU_CORE(dev);

    int smt = kvmppc_smt_threads();

    int i;



    for (i = 0; i < cc->nr_threads; i++) {
@@ -117,7 +116,7 @@ static void spapr_core_release(DeviceState *dev, void *opaque) 
        object_unparent(obj);

    }



    spapr->cores[cc->core_id / smt] = NULL;

    spapr->cores[cc->core_id / smp_threads] = NULL;



    g_free(sc->threads);

    object_unparent(OBJECT(dev));
@@ -128,18 +127,19 @@ void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev, 
{

    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));

    CPUCore *cc = CPU_CORE(dev);

    int smt = kvmppc_smt_threads();

    int index = cc->core_id / smp_threads;

    sPAPRDRConnector *drc =

        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id);

        spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);

    sPAPRDRConnectorClass *drck;

    Error *local_err = NULL;

    int smt = kvmppc_smt_threads();

    int index = cc->core_id / smt;

    int spapr_max_cores = max_cpus / smp_threads;

    int i;



    for (i = spapr_max_cores - 1; i > index; i--) {

        if (spapr->cores[i]) {

            error_setg(errp, "core-id %d should be removed first", i * smt);

            error_setg(errp, "core-id %d should be removed first",

                       i * smp_threads);

            return;

        }

    }
@@ -168,11 +168,10 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev, 
    Error *local_err = NULL;

    void *fdt = NULL;

    int fdt_offset = 0;

    int index;

    int index = cc->core_id / smp_threads;

    int smt = kvmppc_smt_threads();



    drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, cc->core_id);

    index = cc->core_id / smt;

    drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);

    spapr->cores[index] = OBJECT(dev);



    if (!smc->dr_cpu_enabled) {
@@ -226,7 +225,6 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, 
    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));

    int spapr_max_cores = max_cpus / smp_threads;

    int index, i;

    int smt = kvmppc_smt_threads();

    Error *local_err = NULL;

    CPUCore *cc = CPU_CORE(dev);

    char *base_core_type = spapr_get_cpu_core_type(machine->cpu_model);
@@ -247,12 +245,12 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, 
        goto out;

    }



    if (cc->core_id % smt) {

    if (cc->core_id % smp_threads) {

        error_setg(&local_err, "invalid core id %d\n", cc->core_id);

        goto out;

    }



    index = cc->core_id / smt;

    index = cc->core_id / smp_threads;

    if (index < 0 || index >= spapr_max_cores) {

        error_setg(&local_err, "core id %d out of range", cc->core_id);

        goto out;
@@ -266,7 +264,7 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, 
    for (i = 0; i < index; i++) {

        if (!spapr->cores[i]) {

            error_setg(&local_err, "core-id %d should be added first",

                       i * smt);

                       i * smp_threads);

            goto out;

        }

    }