Re: [PATCH 7/9] KVM: x86: simplify dr6 accessors in kvm_x86_ops

[Peter Xu]

On Wed, May 06, 2020 at 06:09:23PM +0200, Paolo Bonzini wrote:
> On 06/05/20 18:06, Peter Xu wrote:
> > On Wed, May 06, 2020 at 07:10:32AM -0400, Paolo Bonzini wrote:
> >> kvm_x86_ops.set_dr6 is only ever called with vcpu->arch.dr6 as the
> >> second argument, and for both SVM and VMX the VMCB value is kept
> >> synchronized with vcpu->arch.dr6 on #DB; we can therefore remove the
> >> read accessor.
> >>
> >> For the write accessor we can avoid the retpoline penalty on Intel
> >> by accepting a NULL value and just skipping the call in that case.
> >>
> >> Suggested-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> > (I think this patch and the previous one seem to be the same as the previous
> >  version.  Anyway...)
> 
> Yes, I placed them here because they are needed to solve the SVM bugs in
> patch 8.  Sorry for not adding your Reviewed-by.

That's not a problem to me. :) Instead I'm more afraid of not noticing some
trivial difference in the patch comparing to the last one.

Thanks,

-- 
Peter Xu