On Tue, 2015-11-10 at 11:27 +0100, Joerg Roedel wrote: > > You have the same problem when real PCIe devices appear that speak > virtio. I think the only real (still not very nice) solution is to add a > quirk to powerpc platform code that sets noop dma-ops for the existing > virtio vendor/device-ids and add a DT property to opt-out of that quirk. > > New vendor/device-ids (as for real devices) would just not be covered by > the quirk and existing emulated devices continue to work. Why woud real devices use new vendor/device IDs ? Also there are other cases such as using virtio between 2 partitions, which we could do under PowerVM ... that would require proper iommu usage with existing IDs. > The absence of the property just means that the quirk is in place and > the system assumes no translation for virtio devices. The only way that works forward for me (and possibly sparc & others, what about ARM ?) is if we *change* something in virtio qemu at the same time as we add some kind of property. For example the ProgIf field or revision ID field. That way I can key on that change. It's still tricky because I would have to somewhat tell my various firmwares (SLOF, OpenBIOS, OPAL, ...) so they can create the appropriate property, it's still hacky, but it would be workable. Ben. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
