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From: Yi Wang <up2wing@gmail.com>
Date: Wed, 24 Jan 2024 10:16:15 +0800
Message-ID: <CAN35MuR-t0THwSQa5ye8inLon3hMCZiHWnu5ofVNxmPJQ6+izg@mail.gmail.com>
Subject: Re: [v2 4/4] KVM: s390: don't setup dummy routing when KVM_CREATE_IRQCHIP
To: Oliver Upton <oliver.upton@linux.dev>
Cc: seanjc@google.com, pbonzini@redhat.com, tglx@linutronix.de, 
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, 
	hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, 
	wanpengli@tencent.com, foxywang@tencent.com, maz@kernel.org, 
	anup@brainfault.org, atishp@atishpatra.org, borntraeger@linux.ibm.com, 
	frankja@linux.ibm.com, imbrenda@linux.ibm.com
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On Wed, Jan 24, 2024 at 2:54=E2=80=AFAM Oliver Upton <oliver.upton@linux.de=
v> wrote:
>
> On Sun, Jan 21, 2024 at 07:17:30PM +0800, Yi Wang wrote:
> > As we have setup empty irq routing in kvm_create_vm(), there's
> > no need to setup dummy routing when KVM_CREATE_IRQCHIP.
> >
> > Signed-off-by: Yi Wang <foxywang@tencent.com>
> > ---
> >  arch/s390/kvm/kvm-s390.c | 13 +++++--------
> >  1 file changed, 5 insertions(+), 8 deletions(-)
> >
> > diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> > index acc81ca6492e..7c836c973b75 100644
> > --- a/arch/s390/kvm/kvm-s390.c
> > +++ b/arch/s390/kvm/kvm-s390.c
> > @@ -2999,14 +2999,11 @@ int kvm_arch_vm_ioctl(struct file *filp, unsign=
ed int ioctl, unsigned long arg)
> >               break;
> >       }
> >       case KVM_CREATE_IRQCHIP: {
> > -             struct kvm_irq_routing_entry routing;
> > -
> > -             r =3D -EINVAL;
> > -             if (kvm->arch.use_irqchip) {
> > -                     /* Set up dummy routing. */
> > -                     memset(&routing, 0, sizeof(routing));
> > -                     r =3D kvm_set_irq_routing(kvm, &routing, 0, 0);
> > -             }
> > +             /*
> > +              * As we have set up empty routing, there is no need to
> > +              * setup dummy routing here.
> > +              */
>
> Where exactly?
>
> In the context of this patch series it is rather obvious, but this
> comment does not stand on its own. You can either throw the reader a
> bone by mentioning where the dummy routing is created or just drop the
> comment altogether.

Yeap, you are right. I will drop this in the upcoming patch.

>
> > +             r =3D 0;
> >               break;
> >       }
> >       case KVM_SET_DEVICE_ATTR: {
> > --
> > 2.39.3
> >
>
> --
> Thanks,
> Oliver


--=20
---
Best wishes
Yi Wang