Re: [kvm-devel] [Qemu-devel] [PATCH] [RFC] Fix time drift of rtc clock + general support

[Avi Kivity]

Paul Brook wrote:
> On Sunday 23 March 2008, Dor Laor wrote:
>   
> > --- a/qemu/hw/irq.c
> > +++ b/qemu/hw/irq.c
> > @@ -30,6 +30,8 @@ struct IRQState {
> >      int n;
> >  };
> >  
> > +uint32_t qemu_irq_acked[NR_IRQ_WORDS];
> >     
>
> This is absolute rubbish. The whole point of the IRQ framework is that it 
> doesn't assume a single flat IRQ controller.
>
>   

x86 does have a single irq space (even when using cascaded pics or 
multiple ioapics), called gsi (for generalized system interrupt, or 
something).  It is possible to enumerate all irqs on all platforms that 
have a finite number of them.

It may be better though to identify an irq by a (controller_id, 
irq_line) pair instead.

--
Do not meddle in the internals of kernels, for they are subtle and quick to 
panic.