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

[Paolo Bonzini]

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.

Paolo

> Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>