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Date: Wed, 10 Oct 2018 13:53:42 +0200
From: Cornelia Huck <cohuck@redhat.com>
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Subject: Re: [Qemu-devel] [qemu-s390x] [PATCH v10 3/6] s390x/kvm: enable AP
 instruction interpretation for guest
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To: Halil Pasic <pasic@linux.ibm.com>
Cc: Tony Krowiak <akrowiak@linux.vnet.ibm.com>, qemu-devel@nongnu.org, peter.maydell@linaro.org, david@redhat.com, pmorel@linux.vnet.ibm.com, fiuczy@linux.ibm.com, eskultet@redhat.com, agraf@suse.de, borntraeger@de.ibm.com, jjherne@linux.vnet.ibm.com, mimu@linux.ibm.com, Tony Krowiak <akrowiak@linux.ibm.com>, heiko.carstens@de.ibm.com, eric.auger@redhat.com, alex.williamson@redhat.com, bjsdjshi@linux.vnet.ibm.com, rth@twiddle.net, mjrosato@linux.vnet.ibm.com, pasic@linux.vnet.ibm.com, berrange@redhat.com, alifm@linux.vnet.ibm.com, qemu-s390x@nongnu.org, schwidefsky@de.ibm.com, pbonzini@redhat.com

On Wed, 10 Oct 2018 13:38:51 +0200
Halil Pasic <pasic@linux.ibm.com> wrote:

> On 10/09/2018 07:52 PM, Tony Krowiak wrote:

> > +static void kvm_s390_configure_apie(bool interpret)
> > +{
> > +    uint64_t attr = interpret ? KVM_S390_VM_CRYPTO_ENABLE_APIE :
> > +                                KVM_S390_VM_CRYPTO_DISABLE_APIE;
> > +
> > +    if (kvm_vm_check_attr(kvm_state, KVM_S390_VM_CRYPTO, attr)) {  
> 
> Not sure this check is necessary, and that the behavior if it fails
> is intuitive, but whatever.

It's not an uncommon pattern, and this is not a call where performance
matters, so it's fine with me.

> 
> > +        kvm_s390_set_attr(attr);
> > +    }
> > +}
> > +