Re: [Qemu-devel] [PATCH v4 08/10] s390x/pci: fence off instructions for non-pci

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 23 Aug 2017 16:10:55 +0200
Halil Pasic <pasic@linux.vnet.ibm.com> wrote:

> On 08/21/2017 11:16 AM, Cornelia Huck wrote:
> > If a guest running on a machine without zpci issues a pci instruction,
> > throw them an exception.
> > 
> > Reviewed-by: Thomas Huth <thuth@redhat.com>
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> > ---
> >  target/s390x/kvm.c | 54 +++++++++++++++++++++++++++++++++++++++++-------------
> >  1 file changed, 41 insertions(+), 13 deletions(-)
> > 
> > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> > index bc62bba5b7..9de165d8b1 100644
> > --- a/target/s390x/kvm.c
> > +++ b/target/s390x/kvm.c
> > @@ -1191,7 +1191,11 @@ static int kvm_clp_service_call(S390CPU *cpu, struct kvm_run *run)
> >  {
> >      uint8_t r2 = (run->s390_sieic.ipb & 0x000f0000) >> 16;
> > 
> > -    return clp_service_call(cpu, r2);
> > +    if (s390_has_feat(S390_FEAT_ZPCI)) {
> > +        return clp_service_call(cpu, r2);
> > +    } else {
> > +        return -1;
> > +    }  
> 
> According to the AR the clp instruction ain't zPCI
> only. OTOH if I read the AR correctly it might be
> the only relevant one at the moment. To be more
> precise, the CLP instruction is installed if one or
> more of certain tree conditions are met. One of the
> conditions is zPCI facility installed, and the other
> two I don't really understand based on what I've
> looked into.

Thx for the info. This sounds like it's ok to leave the check as-is.

> 
> >  }

(...)

> The rest is directly tied to the zPCI facility.
> 
> Reviewed-by: Halil Pasic <pasic@linux.vnet.ibm.com>

Thanks!