Re: [Qemu-devel] [PATCH 06/12] kvmvapic: fixing loading vmstate

[Pavel Dovgaluk]

> From: Paolo Bonzini [mailto:address@hidden
> Il 27/08/2014 14:16, Pavel Dovgaluk ha scritto:
> >> > Can you use a vm_change_state_handler, or a QEMU_CLOCK_VIRTUAL timer
> >> > with expiration time in the past (e.g. at time zero) to run the sync
> >> > code as soon as possible?  Then you can preserve the current migration
> >> > format and avoid using the invalid APIC state.
> > Does this method guarantee, that nobody (like other timers) will access
> > APIC between loading the vmstate and invocation of the timer?
> 
> Hmm, probably not.  The bug would not be other timers accessing the
> APIC, because that would also call apic_sync_vapic and the only effect
> would be an extra useless synchronization.  The bug would happen if the
> APIC is accessed by the CPU before the timer has the occasion to run.

Sorry, but I don't understand which problem we will solve with apic_sync_vapic.
All fields that were added to vmstate are not affected by this function.
Could you explain your idea?

Pavel Dovgalyuk