Re: [Qemu-devel] Re: [Bug 599958] Re: Timedrift problems with Win7: hpet missing time drift fixups

[Gleb Natapov]

On Mon, Jul 05, 2010 at 11:07:56AM +0200, Jan Kiszka wrote:
> Avi Kivity wrote:
> > On 07/05/2010 10:36 AM, Jan Kiszka wrote:
> >>
> >>> Assumes that CPU with
> >>> lowest index is BSP (that one we can actually guaranty if we want
> >>> to).
> >>>      
> >> Well, the generic solution would be returning a bitmap of the CPUs that
> >> were affected, but this is impractical. However, at least x86 should be
> >> fine with the information "state change also on BSP", e.g. like this:
> >>   0 - state change on one or more CPUs, none of them is the BSP
> >>   1 - state change on BSP (and possible more CPUs)
> >>    
> > 
> > What about ack notifiers?  Ask the APIC to notify you when an interrupt
> > is acked.  That allows you to track the BSP, all cpus, or some subset. 
> > Masking can be seen at the irq controller level.
> 
> So, if I understand you correctly, an IRQ state change that is ignored
> due to masking would invoke the ack notifier chain as well?
> 
Ack notifiers go with mask notifiers.

> > 
> > It's more involved, but provides more information.
> 
> Well, it requires to establish ack notifier chains in parallel to the
> existing IRQ delivery routes. Definitely more invasive.
> 
> Jan
> 



--
                        Gleb.