Re: [PATCH v2 4/4] KVM: x86: Add VCPU substate for NMI states

[Gleb Natapov <gleb@redhat.com>]

On Tue, Oct 20, 2009 at 09:13:02AM -0200, Marcelo Tosatti wrote:
> On Tue, Oct 20, 2009 at 06:14:04PM +0900, Avi Kivity wrote:
> > On 10/20/2009 06:08 PM, Gleb Natapov wrote:
> >> On Tue, Oct 20, 2009 at 06:06:36PM +0900, Avi Kivity wrote:
> >>    
> >>> On 10/20/2009 05:56 PM, Jan Kiszka wrote:
> >>>      
> >>>> So save/restore kvm_vcpu_arch::exception? As another substate or as part
> >>>> of a generalized NMI substate?
> >>>>        
> >>> Yes.  It's not part of an nmi substate, but both can be part of an
> >>> exception substate (but need to look at the docs vewy cawefuwy to
> >>> make sure we don't screw up again).
> >>>
> >>>      
> >> What do you mean? How they can be both part of exception substate?
> >>
> >>    
> >
> > Sorry, nomenclature failure.  We need NMI state, Interrupt state  
> > (already provided), and pending exception state (which can be a fault or  
> > a trap).  There's also some extra state associated with pending debug  
> > exceptions (maybe we can copy it into dr6).
> 
> KVM_REQ_TRIPLE_FAULT can also be lost, but i don't think anybody cares?
> 
If pending exception will be migrated KVM_REQ_TRIPLE_FAULT will be restored
after guest will try to re-execute instruction that caused it. One more
reason to migrate pending exceptions. And why not migrate
KVM_REQ_TRIPLE_FAULT while we are at it.

> >
> > We can either put all of these into one substate, or into separate  
> > substates.  I'm not sure which is best.

--
			Gleb.