Re: [Qemu-devel] [PULL 4/4] hw/acpi/vmgenid: prevent more than one vmgenid device

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 22, 2017 at 05:21:32PM +0100, Laszlo Ersek wrote:
> On 03/22/17 17:01, Michael S. Tsirkin wrote:
> > From: Laszlo Ersek <lersek@redhat.com>
> > 
> > A system with multiple VMGENID devices is undefined in the VMGENID spec by
> > omission.
> > 
> > Cc: "Michael S. Tsirkin" <mst@redhat.com>
> > Cc: Ben Warren <ben@skyportsystems.com>
> > Cc: Igor Mammedov <imammedo@redhat.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> > Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> 
> Can you please add the feedback tags from Igor and Ben?
> 
> http://mid.mail-archive.com/23205322-903E-42E2-99D7-ED8351E62694@skyportsystems.com
> http://mid.mail-archive.com/20170321131414.08cc6bfa@nial.brq.redhat.com
> 
> > Binary file /tmp/tmp.IaAwzHwwsQ matches
> 
> I'm not sure what this means.
> 
> Thanks,
> Laszlo

Fixed, thanks for paying attention.

> > ---
> >  include/hw/acpi/vmgenid.h | 1 +
> >  hw/acpi/vmgenid.c         | 8 ++++++++
> >  2 files changed, 9 insertions(+)
> > 
> > diff --git a/include/hw/acpi/vmgenid.h b/include/hw/acpi/vmgenid.h
> > index 8578476..7beb959 100644
> > --- a/include/hw/acpi/vmgenid.h
> > +++ b/include/hw/acpi/vmgenid.h
> > @@ -24,6 +24,7 @@ typedef struct VmGenIdState {
> >      bool write_pointer_available;
> >  } VmGenIdState;
> >  
> > +/* returns NULL unless there is exactly one device */
> >  static inline Object *find_vmgenid_dev(void)
> >  {
> >      return object_resolve_path_type("", VMGENID_DEVICE, NULL);
> > diff --git a/hw/acpi/vmgenid.c b/hw/acpi/vmgenid.c
> > index c3ddcc8..a32b847 100644
> > --- a/hw/acpi/vmgenid.c
> > +++ b/hw/acpi/vmgenid.c
> > @@ -221,6 +221,14 @@ static void vmgenid_realize(DeviceState *dev, Error **errp)
> >          return;
> >      }
> >  
> > +    /* Given that this function is executing, there is at least one VMGENID
> > +     * device. Check if there are several.
> > +     */
> > +    if (!find_vmgenid_dev()) {
> > +        error_setg(errp, "at most one %s device is permitted", VMGENID_DEVICE);
> > +        return;
> > +    }
> > +
> >      qemu_register_reset(vmgenid_handle_reset, vms);
> >  }
> >  
> >