Re: [Qemu-devel] [PATCH v3 8/9] s390x/kvm: msi route fixup for non-pci

[Cornelia Huck <cohuck@redhat.com>]

On Wed, 26 Jul 2017 09:09:06 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 25.07.2017 17:33, Cornelia Huck wrote:
> > If we don't provide pci, we cannot have a pci device for which we
> > have to translate to adapter routes: just return -ENODEV.
> > 
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> > ---
> >  target/s390x/kvm.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> > index dc3f940b95..fb3e21a3a4 100644
> > --- a/target/s390x/kvm.c
> > +++ b/target/s390x/kvm.c
> > @@ -2424,6 +2424,11 @@ int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
> >      uint32_t idx = data >> ZPCI_MSI_VEC_BITS;
> >      uint32_t vec = data & ZPCI_MSI_VEC_MASK;
> >  
> > +    if (!s390_has_feat(S390_FEAT_ZPCI)) {
> > +        DPRINTF("fixup_msi_route on non-pci machine?!\n");
> > +        return -ENODEV;
> > +    }
> > +
> >      pbdev = s390_pci_find_dev_by_idx(s390_get_phb(), idx);
> >      if (!pbdev) {
> >          DPRINTF("add_msi_route no dev\n");
> >   
> 
> Is this additional check really needed here? I'd rather expect
> s390_pci_find_dev_by_idx() to return NULL here already, so we should
> already be fine, shouldn't we?

Yes, the end result is the same, but (1) better safe than sorry and (2)
I can add a debug print here.

I had actually considered throwing an error here, as this function
really should not be called for !pci. Opinions?