Re: [Qemu-devel] [PATCH 09/10] piix: do not raise irq while loading vmstate

[Michael S. Tsirkin]

On Tue, Sep 09, 2014 at 07:16:19PM +0200, Paolo Bonzini wrote:
> Il 09/09/2014 15:54, Michael S. Tsirkin ha scritto:
> > 
> > Hmm I don't understand.
> > You are removing call to piix3_update_irq_levels
> > this call is supposed to just sync up bus to
> > irq level.
> > 
> > How can this change system state? Saved state
> > is supposed to already be in sync.
> 
> i440FX/PIIX3 state is loaded before i8259, so the interrupt will never
> be in the i8259 ISR.  I am not sure why it is a problem for
> record/replay, but I think it's plausible to consider this a bug.  i8259
> state should not be affected by the load of PIIX3 state, since i8259 is
> migrated separately.
> 
> Paolo

Sorry I still don't understand. Why do stuff from vmstate callback then?
How is it different?

I'd like to see a description of a scenario where this patch makes
a difference.

-- 
MST