Re: [Qemu-devel] [RFCv2 01/12] pseries: Always use core objects for CPU construction

[Greg Kurz <groug@kaod.org>]

On Wed, 16 Nov 2016 09:17:44 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> Currently the pseries machine has two paths for constructing CPUs.  On
> newer machine type versions, which support cpu hotplug, it constructs
> cpu core objects, which in turn construct CPU threads.  For older machine
> versions it individually constructs the CPU threads.
> 
> This division is going to make some future changes to the cpu construction
> harder, so this patch unifies them.  Now cpu core objects are always
> created.  This requires some updates to allow core objects to be created
> without a full complement of threads (since older versions allowed a
> number of cpus not a multiple of the threads-per-core).  Likewise it needs
> some changes to the cpu core hot/cold plug path so as not to choke on the
> old machine types without hotplug support.
> 
> For good measure, we move the cpu construction to its own subfunction,
> spapr_init_cpus().
> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  hw/ppc/spapr.c          | 125 +++++++++++++++++++++++++++---------------------
>  hw/ppc/spapr_cpu_core.c |  37 +++++++-------
>  include/hw/ppc/spapr.h  |   1 -
>  3 files changed, 90 insertions(+), 73 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 0cbab24..cbac537 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1687,11 +1687,80 @@ static void spapr_validate_node_memory(MachineState *machine, Error **errp)
>      }
>  }
>  
> +static void spapr_init_cpus(sPAPRMachineState *spapr)
> +{
> +    MachineState *machine = MACHINE(spapr);
> +    MachineClass *mc = MACHINE_GET_CLASS(machine);
> +    char *type = spapr_get_cpu_core_type(machine->cpu_model);
> +    int smt = kvmppc_smt_threads();
> +    int spapr_max_cores, spapr_cores;
> +    int i;
> +
> +    if (!type) {
> +        error_report("Unable to find sPAPR CPU Core definition");
> +        exit(1);
> +    }
> +
> +    if (mc->query_hotpluggable_cpus) {
> +        if (smp_cpus % smp_threads) {
> +            error_report("smp_cpus (%u) must be multiple of threads (%u)",
> +                         smp_cpus, smp_threads);
> +            exit(1);
> +        }
> +        if (max_cpus % smp_threads) {
> +            error_report("max_cpus (%u) must be multiple of threads (%u)",
> +                         max_cpus, smp_threads);
> +            exit(1);
> +        }
> +
> +        spapr_max_cores = max_cpus / smp_threads;
> +        spapr_cores = smp_cpus / smp_threads;
> +    } else {
> +        if (max_cpus != smp_cpus) {
> +            error_report("This machine version does not support CPU hotplug");
> +            exit(1);
> +        }
> +
> +        spapr_max_cores = QEMU_ALIGN_UP(smp_cpus, smp_threads) / smp_threads;
> +        spapr_cores = spapr_max_cores;
> +    }
> +
> +    spapr->cores = g_new0(Object *, spapr_max_cores);
> +    for (i = 0; i < spapr_max_cores; i++) {
> +        int core_id = i * smp_threads;
> +
> +        if (mc->query_hotpluggable_cpus) {
> +            sPAPRDRConnector *drc =
> +                spapr_dr_connector_new(OBJECT(spapr),
> +                                       SPAPR_DR_CONNECTOR_TYPE_CPU,
> +                                       (core_id / smp_threads) * smt);
> +
> +            qemu_register_reset(spapr_drc_reset, drc);
> +        }
> +
> +        if (i < spapr_cores) {
> +            Object *core  = object_new(type);
> +            int nr_threads = smp_threads;
> +
> +            /* Handle the partially filled core for older machine types */
> +            if ((i + 1) * smp_threads >= smp_cpus) {
> +                nr_threads = smp_cpus - i * smp_threads;
> +            }
> +
> +            object_property_set_int(core, nr_threads, "nr-threads",
> +                                    &error_fatal);
> +            object_property_set_int(core, core_id, CPU_CORE_PROP_CORE_ID,
> +                                    &error_fatal);
> +            object_property_set_bool(core, true, "realized", &error_fatal);
> +        }
> +    }
> +    g_free(type);
> +}
> +
>  /* pSeries LPAR / sPAPR hardware init */
>  static void ppc_spapr_init(MachineState *machine)
>  {
>      sPAPRMachineState *spapr = SPAPR_MACHINE(machine);
> -    MachineClass *mc = MACHINE_GET_CLASS(machine);
>      sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(machine);
>      const char *kernel_filename = machine->kernel_filename;
>      const char *initrd_filename = machine->initrd_filename;
> @@ -1706,21 +1775,6 @@ static void ppc_spapr_init(MachineState *machine)
>      long load_limit, fw_size;
>      char *filename;
>      int smt = kvmppc_smt_threads();
> -    int spapr_cores = smp_cpus / smp_threads;
> -    int spapr_max_cores = max_cpus / smp_threads;
> -
> -    if (mc->query_hotpluggable_cpus) {
> -        if (smp_cpus % smp_threads) {
> -            error_report("smp_cpus (%u) must be multiple of threads (%u)",
> -                         smp_cpus, smp_threads);
> -            exit(1);
> -        }
> -        if (max_cpus % smp_threads) {
> -            error_report("max_cpus (%u) must be multiple of threads (%u)",
> -                         max_cpus, smp_threads);
> -            exit(1);
> -        }
> -    }
>  
>      msi_nonbroken = true;
>  
> @@ -1800,44 +1854,7 @@ static void ppc_spapr_init(MachineState *machine)
>  
>      ppc_cpu_parse_features(machine->cpu_model);
>  
> -    if (mc->query_hotpluggable_cpus) {
> -        char *type = spapr_get_cpu_core_type(machine->cpu_model);
> -
> -        if (type == NULL) {
> -            error_report("Unable to find sPAPR CPU Core definition");
> -            exit(1);
> -        }
> -
> -        spapr->cores = g_new0(Object *, spapr_max_cores);
> -        for (i = 0; i < spapr_max_cores; i++) {
> -            int core_id = i * smp_threads;
> -            sPAPRDRConnector *drc =
> -                spapr_dr_connector_new(OBJECT(spapr),
> -                                       SPAPR_DR_CONNECTOR_TYPE_CPU,
> -                                       (core_id / smp_threads) * smt);
> -
> -            qemu_register_reset(spapr_drc_reset, drc);
> -
> -            if (i < spapr_cores) {
> -                Object *core  = object_new(type);
> -                object_property_set_int(core, smp_threads, "nr-threads",
> -                                        &error_fatal);
> -                object_property_set_int(core, core_id, CPU_CORE_PROP_CORE_ID,
> -                                        &error_fatal);
> -                object_property_set_bool(core, true, "realized", &error_fatal);
> -            }
> -        }
> -        g_free(type);
> -    } else {
> -        for (i = 0; i < smp_cpus; i++) {
> -            PowerPCCPU *cpu = cpu_ppc_init(machine->cpu_model);
> -            if (cpu == NULL) {
> -                error_report("Unable to find PowerPC CPU definition");
> -                exit(1);
> -            }
> -            spapr_cpu_init(spapr, cpu, &error_fatal);
> -       }
> -    }
> +    spapr_init_cpus(spapr);
>  
>      if (kvm_enabled()) {
>          /* Enable H_LOGICAL_CI_* so SLOF can talk to in-kernel devices */
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index e0c14f6..424d275 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -46,7 +46,8 @@ static void spapr_cpu_destroy(PowerPCCPU *cpu)
>      qemu_unregister_reset(spapr_cpu_reset, cpu);
>  }
>  
> -void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu, Error **errp)
> +static void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu,
> +                           Error **errp)
>  {
>      CPUPPCState *env = &cpu->env;
>      CPUState *cs = CPU(cpu);
> @@ -166,11 +167,11 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>                       Error **errp)
>  {
>      sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
> +    MachineClass *mc = MACHINE_GET_CLASS(spapr);
>      sPAPRCPUCore *core = SPAPR_CPU_CORE(OBJECT(dev));
>      CPUCore *cc = CPU_CORE(dev);
>      CPUState *cs = CPU(core->threads);
>      sPAPRDRConnector *drc;
> -    sPAPRDRConnectorClass *drck;
>      Error *local_err = NULL;
>      void *fdt = NULL;
>      int fdt_offset = 0;
> @@ -180,7 +181,7 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>      drc = spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_CPU, index * smt);
>      spapr->cores[index] = OBJECT(dev);
>  
> -    g_assert(drc);
> +    g_assert(drc || !mc->query_hotpluggable_cpus);
>  
>      /*
>       * Setup CPU DT entries only for hotplugged CPUs. For boot time or
> @@ -190,13 +191,15 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>          fdt = spapr_populate_hotplug_cpu_dt(cs, &fdt_offset, spapr);
>      }
>  
> -    drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> -    drck->attach(drc, dev, fdt, fdt_offset, !dev->hotplugged, &local_err);
> -    if (local_err) {
> -        g_free(fdt);
> -        spapr->cores[index] = NULL;
> -        error_propagate(errp, local_err);
> -        return;
> +    if (drc) {
> +        sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> +        drck->attach(drc, dev, fdt, fdt_offset, !dev->hotplugged, &local_err);
> +        if (local_err) {
> +            g_free(fdt);
> +            spapr->cores[index] = NULL;
> +            error_propagate(errp, local_err);
> +            return;
> +        }
>      }
>  
>      if (dev->hotplugged) {
> @@ -209,8 +212,11 @@ void spapr_core_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>          /*
>           * Set the right DRC states for cold plugged CPU.
>           */
> -        drck->set_allocation_state(drc, SPAPR_DR_ALLOCATION_STATE_USABLE);
> -        drck->set_isolation_state(drc, SPAPR_DR_ISOLATION_STATE_UNISOLATED);
> +        if (drc) {
> +            sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
> +            drck->set_allocation_state(drc, SPAPR_DR_ALLOCATION_STATE_USABLE);
> +            drck->set_isolation_state(drc, SPAPR_DR_ISOLATION_STATE_UNISOLATED);
> +        }
>      }
>  }
>  
> @@ -227,7 +233,7 @@ 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 (!mc->query_hotpluggable_cpus) {
> +    if (dev->hotplugged && !mc->query_hotpluggable_cpus) {
>          error_setg(&local_err, "CPU hotplug not supported for this machine");
>          goto out;
>      }
> @@ -237,11 +243,6 @@ void spapr_core_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>          goto out;
>      }
>  
> -    if (cc->nr_threads != smp_threads) {
> -        error_setg(&local_err, "threads must be %d", smp_threads);
> -        goto out;
> -    }
> -
>      if (cc->core_id % smp_threads) {
>          error_setg(&local_err, "invalid core id %d", cc->core_id);
>          goto out;
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index bd5bcf7..f8d444d 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -614,7 +614,6 @@ void spapr_hotplug_req_add_by_count_indexed(sPAPRDRConnectorType drc_type,
>                                              uint32_t count, uint32_t index);
>  void spapr_hotplug_req_remove_by_count_indexed(sPAPRDRConnectorType drc_type,
>                                                 uint32_t count, uint32_t index);
> -void spapr_cpu_init(sPAPRMachineState *spapr, PowerPCCPU *cpu, Error **errp);
>  void *spapr_populate_hotplug_cpu_dt(CPUState *cs, int *fdt_offset,
>                                      sPAPRMachineState *spapr);
>