On Thu, Aug 09, 2018 at 08:13:32AM +1000, Benjamin Herrenschmidt wrote:

quoted

quoted

-	if (xen_domain())
+	if (xen_domain() || pseries_secure_vm())
		return true;

I don't think it's pseries specific actually. E.g. I suspect AMD SEV
might benefit from the same kind of hack.

As long as they can provide the same guarantee that the DMA ops are
completely equivalent between virtio and other PCI devices, at least on
the same bus, ie, we don't have to go hack special DMA ops.

I think the latter is really what Christoph wants to avoid for good
reasons.

Yes.  I also generally want to avoid too much arch specific magic.

FYI, I'm off to a week-long vacation today, don't expect quick replies.