Re: ioapic/msi interrupt delivery consolidation.

[Sheng Yang <sheng@linux.intel.com>]

On Wednesday 11 March 2009 00:54:37 Mike Day wrote:
> On 05/03/09 16:34 +0200, Gleb Natapov wrote:
> > ioapic_deliver() and kvm_set_msi() have code duplication. Move
> > the code into ioapic_deliver_entry() function and call it from
> > both places.
> >
> >
> > +static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
> > +{
> > +	union kvm_ioapic_redirect_entry entry = ioapic->redirtbl[irq];
> > +
> > +	ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
> > +		     "vector=%x trig_mode=%x\n",
> > +		     entry.fields.dest, entry.fields.dest_mode,
> > +		     entry.fields.delivery_mode, entry.fields.vector,
> > +		     entry.fields.trig_mode);
> > +
> > +#ifdef CONFIG_X86
> > +	/* Always delivery PIT interrupt to vcpu 0 */
> > +	if (irq == 0) {
> > +		entry.fields.dest_mode = 0; /* Physical mode. */
> > +		entry.fields.dest_id = ioapic->kvm->vcpus[0]->vcpu_id;
> > +	}
> > +#endif
> > +	return ioapic_deliver_entry(ioapic->kvm, &entry);
> > +}
> > +
>
> Why is the PIT always handled by vcpu 0?
>
> thanks,

Hi Mike

This due to a timer bug, please google "The SMP RHEL 5.1 PAE guest can't boot 
up issue". (should be http://www.mail-archive.com/kvm-
devel@lists.sourceforge.net/msg13250.html but damn it, seems I've blocked by 
Chinese GFW to get the page...)

-- 
regards
Yang, Sheng