Re: [Qemu-devel] [PATCH 1/5] apic: add global apic_get_class()

[Peter Xu <peterx@redhat.com>]

On Thu, Sep 22, 2016 at 11:04:28PM +0200, Radim Krčmář wrote:
> Every configuration has only up to one APIC class and we'll be extending
> the class with a function that can be called without an instanced
> object, so a direct access to the class is convenient.
> 
> Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
> ---
>  hw/intc/apic_common.c           | 14 ++++++++++++++
>  include/hw/i386/apic_internal.h |  3 +++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
> index 14ac43c18666..86ef9c43e6df 100644
> --- a/hw/intc/apic_common.c
> +++ b/hw/intc/apic_common.c
> @@ -18,6 +18,7 @@
>   * License along with this library; if not, see <http://www.gnu.org/licenses/>
>   */
>  #include "qemu/osdep.h"
> +#include "qemu/error-report.h"
>  #include "qapi/error.h"
>  #include "qemu-common.h"
>  #include "cpu.h"
> @@ -296,6 +297,13 @@ static int apic_load_old(QEMUFile *f, void *opaque, int version_id)
>  
>  static const VMStateDescription vmstate_apic_common;
>  
> +APICCommonClass *apic_class;
> +
> +APICCommonClass *apic_get_class(void)
> +{
> +    return apic_class;
> +}
> +
>  static void apic_common_realize(DeviceState *dev, Error **errp)
>  {
>      APICCommonState *s = APIC_COMMON(dev);
> @@ -306,6 +314,12 @@ static void apic_common_realize(DeviceState *dev, Error **errp)
>      info = APIC_COMMON_GET_CLASS(s);
>      info->realize(dev, errp);
>  
> +    if (apic_class && apic_class != info) {
> +        error_report("All APICs must be of the same class.");
> +        exit(1);
> +    }

Can user trigger this error? If not, I'd prefer:

  assert(!apic_class || apic_class == info);

Thanks,

-- peterx