Re: [Qemu-devel] [PATCH 09/19] cpu: add helper cpu_exists(), to check if CPU with specified id exists

[Eduardo Habkost]

On Thu, Apr 11, 2013 at 04:51:48PM +0200, Igor Mammedov wrote:
> ... it should be used only on slow path since it does recursive search
>     on /machine QOM tree for objects of TYPE_CPU
> 
> Signed-off-by: Igor Mammedov <address@hidden>
> Reviewed-by: Paolo Bonzini <address@hidden>

Why not implement this only after patch 21/22, and use
"/machine/icc-bridge/cpu[ID]" for the lookup?


> ---
> v2:
>   * s/get_firmware_id()/get_arch_id()/ rebase fixup
>   * remove check for get_arch_id being NULL, since it's always defined
> ---
>  include/qom/cpu.h | 10 ++++++++++
>  qom/cpu.c         | 21 +++++++++++++++++++++
>  2 files changed, 31 insertions(+)
> 
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index b376416..cd7c4b5 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -225,6 +225,16 @@ void run_on_cpu(CPUState *cpu, void (*func)(void *data), 
> void *data);
>   */
>  CPUState *qemu_get_cpu(int index);
>  
> +/**
> + * cpu_exists:
> + * @id - guest exposed CPU ID to lookup
> + *
> + * Search for CPU with specified ID.
> + *
> + * Returns: true - CPU is found, false - CPU isn't found
> + */
> +bool cpu_exists(int64_t id);
> +
>  #ifndef CONFIG_USER_ONLY
>  
>  typedef void (*CPUInterruptHandler)(CPUState *, int);
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 90cbd77..c850d27 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -25,6 +25,27 @@
>  #include "qemu/notify.h"
>  #include "sysemu/sysemu.h"
>  
> +static int cpu_exist_cb(Object *obj, void *opaque)
> +{
> +    int64_t id = *(int64_t *)opaque;
> +    Object *cpu_obj = object_dynamic_cast(obj, TYPE_CPU);
> +
> +    if (cpu_obj) {
> +        CPUState *cpu = CPU(cpu_obj);
> +        CPUClass *klass = CPU_GET_CLASS(cpu);
> +
> +        if (klass->get_arch_id(cpu) == id) {
> +            return 1;
> +        }
> +    }
> +    return object_child_foreach(obj, cpu_exist_cb, opaque);
> +}
> +
> +bool cpu_exists(int64_t id)
> +{
> +   return cpu_exist_cb(qdev_get_machine(), &id) ? true : false;
> +}
> +
>  /* CPU hot-plug notifiers */
>  static NotifierList cpu_added_notifiers =
>      NOTIFIER_LIST_INITIALIZER(cpu_add_notifiers);
> -- 
> 1.8.2
> 

-- 
Eduardo