linux-kernel - Re: [PATCH 11/19] KVM: SVM: Add helper to perform final AVIC "kick" of single vCPU

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Date:   Wed, 31 Aug 2022 21:12:56 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>
Cc:     Paolo Bonzini <pbonzini@...hat.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Li RongQing <lirongqing@...du.com>
Subject: Re: [PATCH 11/19] KVM: SVM: Add helper to perform final AVIC "kick"
 of single vCPU

On Wed, 2022-08-31 at 15:08 +0000, Sean Christopherson wrote:
> On Wed, Aug 31, 2022, Maxim Levitsky wrote:
> > On Wed, 2022-08-31 at 00:34 +0000, Sean Christopherson wrote:
> > > @@ -455,13 +461,8 @@ static void avic_kick_target_vcpus(struct kvm *kvm, struct kvm_lapic *source,
> > >  	 */
> > >  	kvm_for_each_vcpu(i, vcpu, kvm) {
> > >  		if (kvm_apic_match_dest(vcpu, source, icrl & APIC_SHORT_MASK,
> > > -					dest, icrl & APIC_DEST_MASK)) {
> > > -			vcpu->arch.apic->irr_pending = true;
> > > -			svm_complete_interrupt_delivery(vcpu,
> > > -							icrl & APIC_MODE_MASK,
> > > -							icrl & APIC_INT_LEVELTRIG,
> > > -							icrl & APIC_VECTOR_MASK);
> > > -		}
> > > +					dest, icrl & APIC_DEST_MASK))
> > > +			avic_kick_vcpu(vcpu, icrl);
> > >  	}
> > >  }
> > >  
> > 
> > I don't know what I think about this, sometimes *minor* code duplication
> > might actually be a good thing, as it is easier to read the code, but I don't
> > have much against this as well.
> > 
> > I am not sure if before or after this code is more readable.
> 
> I don't have a strong opinion either.  I think I prefer having the helper, but
> have no objection to leaving things as is.  Originally I was thinking there was
> going to be a third call site, but that didn't happen.
> 

Yep - when something is duplicated 3 times, it is really rare to not want to have a helper,
Anyway I don't have a strong opinion about this either.

I mostly was unsure about the fact that helper receives icrl and not icrh, kind of wierd,
but anyway let it be.

Best regards,
	Maxim Levitsky