Re: [PATCH] KVM: x86: optimize PKU branching in kvm_load_{guest|host}_xsave_state

[Sean Christopherson]

On Mon, Mar 28, 2022, Jon Kohler wrote:
> 
> 
> > On Mar 27, 2022, at 6:43 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> > 
> > On 3/26/22 02:37, Jon Kohler wrote:
> >>>>    Flip the ordering of the || condition so that XFEATURE_MASK_PKRU is
> >>>>    checked first, which when instrumented in our environment appeared
> >>>>    to be always true and less overall work than kvm_read_cr4_bits.
> >>> 
> >>> If it's always true, then it should be checked last, not first.  And if
> >> Sean thanks for the review. This would be a left handed || short circuit, so
> >> wouldn’t we want always true to be first?
> > 
> > Yes.
> 
> Ack, thanks.

Yeah, I lost track of whether it was a || or &&.