Re: [Qemu-devel] [RFC/PATCH 2] kvm: x86: handle KVM_SET_VCPU_EVENTS/KVM_VCPUEVENT_VALID_SMM properly

[Herongguang (Stephen)]

On 2016/9/22 17:29, Paolo Bonzini wrote:
> On 22/09/2016 09:51, Herongguang (Stephen) wrote:
> > After making memory consistent between source and destination
> > (https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03069.html),
> > there can
> > still reproduce instruction emulation failure in destination side if
> > migration when VM’s in grub stage:
>
> Hi!  Did you follow up on that patch, by the way?
Yes, I have some concern, see that post.

> > So I think there is some lacking in kvm-kmod’s
> > kvm_vcpu_ioctl_x86_set_vcpu_events that handles KVM_VCPUEVENT_VALID_SMM.
> > I tried following patch,
> > it seems works fine.
> >
> > Do you think this patch is appropriate or not enough? Thanks.
>
> Yes.  I would just call kvm_mmu_reset_context unconditionally at the end
> of kvm_vcpu_iocyl_x86_set_x86_vcpu_events.  Please send this patch as
> non-RFC.
>
> Patch 3 is also okay, please send it separately.
Ok, I will test and post it tomorrow, thanks!

> Thanks,
>
> Paolo
>
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 19f9f9e..f39e839 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -3013,8 +3013,10 @@ static int
> > kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
> >                  vcpu->arch.apic->sipi_vector = events->sipi_vector;
> >
> >          if (events->flags & KVM_VCPUEVENT_VALID_SMM) {
> > -               if (events->smi.smm)
> > +               if (events->smi.smm) {
> >                          vcpu->arch.hflags |= HF_SMM_MASK;
> > +                       kvm_mmu_reset_context(vcpu);
> > +               }
> >                  else
> >                          vcpu->arch.hflags &= ~HF_SMM_MASK;
> >                  vcpu->arch.smi_pending = events->smi.pending;
>
> .