[Qemu-devel] Re: [PATCH 8/8] kvm: Rework VCPU reset

[Avi Kivity]

Jan Kiszka wrote:
> Avi Kivity wrote:
>   
> > Jan Kiszka wrote:
> >     
> > > Avi Kivity wrote:
> > >  
> > >       
> > > > Jan Kiszka wrote:
> > > >    
> > > >         
> > > > > Use standard callback with highest order to synchronize VCPU on reset
> > > > > after all device callbacks were execute. This allows to remove the
> > > > > special kvm hook in qemu_system_reset.
> > > > >         
> > > > >           
> > > > Is this needed for the lapic reset callback?
> > > >
> > > > If so, we can express the dependency explicitly rather than with a
> > > > priority, by having cpu reset notifiers invoked when the cpu is
> > > > reset. In the case of the lapic, I don't think we need an abstract
> > > > mechanism;
> > > > the lapic is part of the cpu, not some random device.
> > > >
> > > > Maybe we should even save/load it as part of the cpu.
> > > >
> > > >     
> > > >         
> > > QEMU is not only providing the LAPIC, but also covering the old
> > > dedicated version. That makes at least HW instantiating a bit more
> > > complex.
> > >
> > >   
> > >       
> > What do you mean by 'old dedicated version'?
> >     
>
> Separate chip, not part of the CPU. Some 486 system used to have this IIRC.
>
>   

Yes, you're right.

Maybe we can have a vcpu reset callback for the lapic.

--
Do not meddle in the internals of kernels, for they are subtle and quick to 
panic.