Re: [Qemu-devel] [PATCH 57/61] ioapic: add callback when entry is set or ioapic is reset

[Avi Kivity]

On 10/01/2009 03:37 PM, Gleb Natapov wrote:
> On Wed, Sep 30, 2009 at 07:18:33PM +0900, Isaku Yamahata wrote:
>    
> > Add hooks to ioapic.
> > This is necessary for pci interrupt routing mode from
> > PIC mode to IO APIC mode.
> >      
> According to my very brief looking at ICH9 spec switching from PIC mode
> to IO APIC mode is done separately for each PIRQ by setting bit 7 of
> PIRQ[n]_ROUT register to 1. This callback looks completely out of place.
>    

Disassembling the _PIC and _PRT methods of a Q35 machine will probably 
yield how this is done on real hardware.

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