Re: [Qemu-devel] [PATCH v1 4/5] s390x/pci: Refuse to realize VFIO-PCI if AIS needed but supported

[Pierre Morel]

On 11/10/2017 14:20, Cornelia Huck wrote:
> On Tue, 10 Oct 2017 18:01:53 +0200
> Pierre Morel <address@hidden> wrote:
>
> > Since in the case we have no AIS in KVM only PCI is impacted, do you
> > think we can fence IRQFD for MSI with
> >
> > kvm_msi_via_irqfd_allowed = false;
> >
> > in kvm_arch_init_irq_routing() ?
>
> Hm, it seems we never set that for s390x... does that imply that we
> never support irqfd for pci anyway?

... yes, we never supported irqfd for virtio-pci anyway.
This explains a lot of things to me.
:)

> > In fact, if we also verify the AIS availability in the same routine we
> > can avoid the ugly include of vfio/pci.h
>
> If we can get the serialization right (and setting that value to false
> does indeed have the desired effect), that's probably the way to go.

So now, in v2, we will be able to **enable** irqfd if we detect that we 
handle AIS in kernel. :)


--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany