Re: [PATCH v3 03/37] KVM: nVMX: Invalidate all EPTP contexts when emulating INVEPT for L1

[Sean Christopherson]

On Mon, Mar 23, 2020 at 05:12:04PM -0700, Jim Mattson wrote:
> On Mon, Mar 23, 2020 at 4:51 PM Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> >
> > On 23/03/20 17:44, Sean Christopherson wrote:
> > > So I think
> > >
> > >   Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
> > >
> > > would be appropriate?
> > >
> >
> > Yes.
> 
> I think it was actually commit efebf0aaec3d ("KVM: nVMX: Do not flush
> TLB on L1<->L2 transitions if L1 uses VPID and EPT").

Hmm, commit efebf0aaec3d it only changed flushing behavior, it didn't
affect KVM's behavior with respect to refreshing unsync'd SPTE, i.e.
reloading guest_mmu.

It's somewhat of a moot point, because _technically_ there is no bug since,
at the time of this fix, KVM always flushes and reloads on nested VM-Enter.