Re: qemu polling KVM_IRQ_LINE_STATUS when stopped

[Andi Kleen <ak@linux.intel.com>]

On Fri, Oct 20, 2017 at 05:12:40PM +0200, Paolo Bonzini wrote:
> On 20/10/2017 16:09, Andi Kleen wrote:
> >> Unfortunately that's not possible in general.  Windows uses the periodic
> >> timer to track wall time (!), so if you do that your clock is going to
> >> be late when you resume the guest.
> > 
> > But when the guest cannot execute instructions 
> > it cannot see whatever the handler does.
> > 
> > So the handler could always catch up after stopping for longer,
> > without making any difference.
> 
> You may be right... you should get the interrupt storm *after
> continuing* the guest, but not while it's stopped.

Maybe be find to not have a storm, but only one. I belive real hardware
cannot have a storm because only one interrupt can be pending at a time.
The RTC driver should be able to figure it out from the actual time,
and it already needs to handle it because this can happen for other
reasons (e.g. a JTAG debugger)

-Andi