Re: [Qemu-devel] [PATCH v4 8/9] s390x/kvm: msi route fixup for non-pci

[Cornelia Huck <cohuck@redhat.com>]

On Fri, 4 Aug 2017 15:18:14 +0200
David Hildenbrand <david@redhat.com> wrote:

> On 04.08.2017 13:29, 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 | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c
> > index 9de165d8b1..d8db1cbf6e 100644
> > --- a/target/s390x/kvm.c
> > +++ b/target/s390x/kvm.c
> > @@ -2424,6 +2424,12 @@ 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)) {
> > +        /* How can we get here without pci enabled? */
> > +        g_assert(false);
> > +        return -ENODEV;
> > +    }
> > +  
> 
> /* How can we get here without pci enabled? */
> g_assert(s390_has_feat(S390_FEAT_ZPCI));
> 
> ?

What I don't like about this is that it implicitly relies on
s390_pci_find_dev_by_idx() doing the correct thing if asserts are off -
and it is non-obvious that we'll get pbdev == NULL in that case.

> 
> >      pbdev = s390_pci_find_dev_by_idx(s390_get_phb(), idx);
> >      if (!pbdev) {
> >          DPRINTF("add_msi_route no dev\n");
> >   
> 
>