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

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 11 Apr 2013 16:06:58 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> 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 <imammedo@redhat.com>
> > Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> Why not implement this only after patch 21/22, and use
> "/machine/icc-bridge/cpu[ID]" for the lookup?
/machine/icc-bridge/cpu[ID] is target specific and optional so far,
+ it would require parsing links names.

While looking for all CPUs, regardless of where they are located
(each target could have its own notion about it) are generic.

BTW:
patches 10/19 and 11/19 use it as well.

> 
> > ---
> > 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


-- 
Regards,
  Igor