Re: [PATCH 1/1] KVM: s390: index kvm->arch.idle_mask by vcpu_idx

From: Halil Pasic
Date: Fri Aug 27 2021 - 17:23:57 EST


On Fri, 27 Aug 2021 18:36:48 +0200
Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote:

> On 27.08.21 16:06, Claudio Imbrenda wrote:
> > On Fri, 27 Aug 2021 14:54:29 +0200
> > Halil Pasic <pasic@xxxxxxxxxxxxx> wrote:
> >
> >> While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true,

s/vcp_id/vcpu_id/

> >> it may not always be, and we must not rely on this.
> >
> > why?
> >
> > maybe add a simple explanation of why vcpu_idx and vcpu_id can be
> > different, namely:
> > KVM decides the vcpu_idx, userspace decides the vcpu_id, thus the two
> > might not match
> >
> >>
> >> Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies
> >> that code like
> >> for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) {
> >> vcpu = kvm_get_vcpu(kvm, vcpu_id);
> >
> > you can also add a sentence to clarify that kvm_get_vcpu expects an
> > vcpu_idx, not an vcpu_id.
> >
> >> do_stuff(vcpu);
>
> I will modify the patch description accordingly before sending to Paolo.
> Thanks for noticing.

Can you also please fix the typo I pointed out above (in the first line
of the long description).

Thanks!
Halil