Re: [Qemu-devel] [PATCH v2 1/5] acpi, pc: Add hotunplug request cb for pc machine.

[Zhu Guihua <zhugh.fnst@cn.fujitsu.com>]

On Wed, 2015-01-28 at 10:02 +0200, Michael S. Tsirkin wrote:
> On Wed, Jan 28, 2015 at 03:45:37PM +0800, Zhu Guihua wrote:
> > From: Tang Chen <tangchen@cn.fujitsu.com>
> > 
> > Memory and CPU hot unplug are both asynchronous procedures.
> > They both need unplug request callback to initiate unplug operation.
> > 
> > Add unplug handler to pc machine that will be used by following
> > CPU and memory unplug patches.
> > 
> > Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> > Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
> > Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
> > ---
> >  hw/i386/pc.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> > index c7af6aa..15ee10a 100644
> > --- a/hw/i386/pc.c
> > +++ b/hw/i386/pc.c
> > @@ -1680,6 +1680,13 @@ static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev,
> >      }
> >  }
> >  
> > +static void pc_machine_device_unplug_request_cb(HotplugHandler *hotplug_dev,
> > +                                                DeviceState *dev, Error **errp)
> > +{
> > +    error_setg(errp, "acpi: device unplug request for not supported device"
> > +               " type: %s", object_get_typename(OBJECT(dev)));
> > +}
> > +
> >  static HotplugHandler *pc_get_hotpug_handler(MachineState *machine,
> >                                               DeviceState *dev)
> >  {
> 
> 
> So this is just a stub, your follow-up patches replace it with
> something more useful?
> 
> Why do we need the stub stage though?
> Why not just add whatever's going to be there eventually?
> 

This function will be used in memory hot-unplug
[RESEND PATCH v1 07/13] pc-dimm: Add memory hot unplug request support
for pc-dimm.
https://lists.nongnu.org/archive/html/qemu-devel/2015-01/msg00592.html

and cpu hot-unplug
[PATCH v2 05/11] pc: add cpu hot unplug request callback support
https://lists.nongnu.org/archive/html/qemu-devel/2015-01/msg01562.html

Regards,
Zhu

> 
> > @@ -1809,6 +1816,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
> >      pcmc->get_hotplug_handler = mc->get_hotplug_handler;
> >      mc->get_hotplug_handler = pc_get_hotpug_handler;
> >      hc->plug = pc_machine_device_plug_cb;
> > +    hc->unplug_request = pc_machine_device_unplug_request_cb;
> >  }
> >  
> >  static const TypeInfo pc_machine_info = {
> > -- 
> > 1.9.3