Re: [PATCH v10 2/3] KVM: s390: guest support for topology function

[Pierre Morel]

On 6/24/22 08:56, Nico Boehr wrote:
> Quoting Pierre Morel (2022-06-20 14:54:36)
> [...]
> > diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
> > index 766028d54a3e..bb54196d4ed6 100644
> > --- a/arch/s390/include/asm/kvm_host.h
> > +++ b/arch/s390/include/asm/kvm_host.h
> [...]
> > @@ -3403,6 +3426,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
> >          rc = kvm_s390_vcpu_setup(vcpu);
> >          if (rc)
> >                  goto out_ucontrol_uninit;
> > +
> > +       kvm_s390_sca_set_mtcr(vcpu->kvm);
>
> We set the MTCR in the vcpu create. Does it also make sense to set it in kvm_arch_vcpu_destroy?
>
> [...]
> > diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c
> > index 12c464c7cddf..77a692238585 100644
> > --- a/arch/s390/kvm/priv.c
> > +++ b/arch/s390/kvm/priv.c
> > @@ -873,10 +873,13 @@ static int handle_stsi(struct kvm_vcpu *vcpu)
> [...]
> > +       case 15:
> > +               trace_kvm_s390_handle_stsi(vcpu, fc, sel1, sel2, operand2);
> > +               insert_stsi_usr_data(vcpu, operand2, ar, fc, sel1, sel2);
> > +               return -EREMOTE;
>
> Maybe the API documentation should clearly note that once you turn on KVM_CAP_S390_CPU_TOPOLOGY, you will get exits to userspace for STSI 15.x.y, regardless of whether KVM_CAP_S390_USER_STSI is on or off.

Humm, right, I must change this, it is not right to have STSI(15) but 
not STSI([123])

I will also have two other changes in this patch, the locking and add a 
check for PV on STSI(15)

So I will respin in a short time.


> Other than that, looks good, hence:
>
> Reviewed-by: Nico Boehr <nrb@xxxxxxxxxxxxx>

--
Pierre Morel
IBM Lab Boeblingen