Re: [Qemu-devel] [PATCH 8/8] qom: Make CPU a child of DeviceState

["Andreas Färber" <afaerber@suse.de>]

Am 05.12.2012 17:49, schrieb Eduardo Habkost:
> This finally makes the CPU class a child of DeviceState, allowing us to
> start using DeviceState properties on CPU subclasses.
> 
> It has no_user=1, as creating CPUs using -device doesn't work yet.
> 
> (based on a previous patch from Igor Mammedov)
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> ---
> Changes v1 (imammedo) -> v2 (ehabkost):
>  - Change CPU type declaration to hae TYPE_DEVICE as parent
> 
> Changes v2 -> v3 (ehabkost):
>  - Set no_user=1 on the CPU class
> ---
>  include/qemu/cpu.h | 6 +++---
>  qom/cpu.c          | 5 ++++-
>  2 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/include/qemu/cpu.h b/include/qemu/cpu.h
> index 61b7698..bc004fd 100644
> --- a/include/qemu/cpu.h
> +++ b/include/qemu/cpu.h
> @@ -20,7 +20,7 @@
>  #ifndef QEMU_CPU_H
>  #define QEMU_CPU_H
>  
> -#include "qemu/object.h"
> +#include "hw/qdev-core.h"
>  #include "qemu-thread.h"
>  
>  /**
> @@ -46,7 +46,7 @@ typedef struct CPUState CPUState;
>   */
>  typedef struct CPUClass {
>      /*< private >*/
> -    ObjectClass parent_class;
> +    DeviceClass parent_class;
>      /*< public >*/
>  
>      void (*reset)(CPUState *cpu);
> @@ -62,7 +62,7 @@ typedef struct CPUClass {
>   */
>  struct CPUState {
>      /*< private >*/
> -    Object parent_obj;
> +    DeviceState parent_obj;
>      /*< public >*/
>  
>      struct QemuThread *thread;
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 5b36046..d301f72 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -20,6 +20,7 @@
>  
>  #include "qemu/cpu.h"
>  #include "qemu-common.h"
> +#include "hw/qdev-core.h"
>  
>  void cpu_reset(CPUState *cpu)
>  {
> @@ -36,14 +37,16 @@ static void cpu_common_reset(CPUState *cpu)
>  
>  static void cpu_class_init(ObjectClass *klass, void *data)
>  {
> +    DeviceClass *dc = DEVICE_CLASS(klass);
>      CPUClass *k = CPU_CLASS(klass);
>  
>      k->reset = cpu_common_reset;
> +    dc->no_user = 1;
>  }
>  
>  static TypeInfo cpu_type_info = {
>      .name = TYPE_CPU,
> -    .parent = TYPE_OBJECT,
> +    .parent = TYPE_DEVICE,
>      .instance_size = sizeof(CPUState),
>      .abstract = true,
>      .class_size = sizeof(CPUClass),

This patch makes the CPU a device and looks good so far but does not
initialize the devices in cpu_*_init() like Anthony did in his previous
patch. I am unsure whether you forgot to do so or whether you wanted to
help keep our new CPU code clean of old-style qdev_init_nofail() calls?
Since you don't add a qdev initfn here the main difference will be the
devices internally staying in "created" rather than "initialized" state.

If we merge some patch that adds the "realized" property first (probably
not through qom-cpu tree then) we could avoid qdev_init*() but the end
result targetted by Paolo was not to have object creators worry about
realization at all through recursive realization. So either solution
needs to be changed later on.

Andreas

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