Re: [Qemu-devel] [PATCH 16/27] acpi: ich9: allow guest to clear SCI rised by GPE

[Li Guang]

Igor Mammedov wrote:
> On Thu, 21 Nov 2013 16:32:27 +0800
> Li Guang<address@hidden>  wrote:
>
>    
> > Michael S. Tsirkin wrote:
> >      
> > > On Thu, Nov 21, 2013 at 04:18:45PM +0800, Li Guang wrote:
> > >
> > >        
> > > > Hu Tao wrote:
> > > >
> > > >          
> > > > > On Thu, Nov 21, 2013 at 09:14:18AM +0200, Michael S. Tsirkin wrote:
> > > > >
> > > > >            
> > > > > > On Thu, Nov 21, 2013 at 03:38:37AM +0100, Igor Mammedov wrote:
> > > > > >
> > > > > >              
> > > > > > > it fixes IRQ storm since guest isn't able to lower SCI IRQ
> > > > > > > after it has been handled when it clears GPE event.
> > > > > > >
> > > > > > > Signed-off-by: Igor Mammedov<address@hidden>
> > > > > > >
> > > > > > >                
> > > > > > The storm is only on memory hotplug right?
> > > > > >
> > > > > >              
> > > > > IIRC, it happens on cpu hotplug, too.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >            
> > > > :-), that made remember EC implementation,
> > > > with EC, SCI will be safer, I think.
> > > >
> > > >          
> > > Hmm you are saying let's use EC for memory hotplug?
> > >
> > >
> > >
> > >        
> > It can be a bridge between guest and QEMU,
> > with it, we may don't have to bother ASL writing
> > and south-bridge hardware related work(or very
> > little) if we implement EC correctly.
> >
> >      
> Wouldn't it require guest driver though?
> Beauty of ASL/GPE it's that it supported by Windows and Linux
> out of box.
>
>    

it did require guest driver, but as a ACPI standard device,
the driver is natively implemented by ACPI compatible OS.