Re: [Qemu-devel] [PATCH V4 4/8] pc: add cpu hotplug handler to PC_MACHINE

[Igor Mammedov <imammedo@redhat.com>]

On Mon, 29 Sep 2014 18:52:33 +0800
Gu Zheng <guz.fnst@cn.fujitsu.com> wrote:

> Add cpu hotplug handler to PC_MACHINE, which will perform the acpi
> cpu hotplug callback via hotplug_handler API.
> 
> v3:
>  -deal with start up cpus in a more neat way as Igor suggested.
> v2:
>  -just rebase.
> 
> Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
> ---
>  hw/i386/pc.c |   26 +++++++++++++++++++++++++-
>  1 files changed, 25 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 82a7daa..dcb9332 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1616,11 +1616,34 @@ out:
>      error_propagate(errp, local_err);
>  }
>  
> +static void pc_cpu_plug(HotplugHandler *hotplug_dev,
> +                        DeviceState *dev, Error **errp)
> +{
> +    HotplugHandlerClass *hhc;
> +    Error *local_err = NULL;
> +    PCMachineState *pcms = PC_MACHINE(hotplug_dev);
> +
> +    if (!pcms->acpi_dev) {
> +        if (dev->hotplugged) {
it could be better to move this check out of acpi_dev block
so it wouldn't rely on acpi_dev being uninitialized for
initial CPUs.
 
> +            error_setg(&local_err,
> +                       "cpu hotplug is not enabled: missing acpi device");
> +        }
> +        goto out;
> +    }

something like this:

    if (!pcms->acpi_dev) {
        error_setg(&local_err, "missing acpi device");
        goto out;
    }

    if (!dev->hotplugged) {
        goto out;
    }

> +    hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
> +    hhc->plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
> +out:
> +    error_propagate(errp, local_err);
> +}
> +
>  static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev,
>                                        DeviceState *dev, Error **errp)
>  {
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
>          pc_dimm_plug(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> +        pc_cpu_plug(hotplug_dev, dev, errp);
>      }
>  }
>  
> @@ -1629,7 +1652,8 @@ static HotplugHandler *pc_get_hotpug_handler(MachineState *machine,
>  {
>      PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(machine);
>  
> -    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
> +        object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
>          return HOTPLUG_HANDLER(machine);
>      }
>