On Tue, Nov 10, 2015 at 2:27 PM, Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 2015-11-10 at 10:54 -0800, Andy Lutomirski wrote: >> >> Does that work on powerpc on existing kernels? >> >> Anyway, here's another crazy idea: make the quirk assume that the >> IOMMU is bypasses if and only if the weak barriers bit is set on >> systems that are missing the new DT binding. > > "New DT bindings" doesn't mean much ... how do we change DT bindings on > existing machines with a FW in flash ? > > What about partition <-> partition virtio such as what we could do on > PAPR systems. That would have the weak barrier bit. > Is it partition <-> partition, bypassing IOMMU? I think I'd settle for just something that doesn't regress non-experimental setups that actually work today and that allow new setups (x86 with fixed QEMU and maybe something more complicated on powerpc and/or sparc) to work in all cases. We could certainly just make powerpc and sparc continue bypassing the IOMMU until someone comes up with a way to fix it. I'll send out some patches that do that, and maybe that'll help this make progress. --Andy -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
