Pawel Moll <pawel.moll@xxxxxxx> writes: > On Mon, 2013-10-14 at 11:46 +0100, Michael S. Tsirkin wrote: >> What I meant is that under the proposed scheme, users with >> existing v1 drivers must configure a v1 device explicitly. >> >> According to the plan, drivers will be updated so they can >> work with both v1 devices and new v2 devices. >> >> But if you configure a v2 device, old drivers >> will not work. > > That's correct, yes. If qemu 2015(16? 17?).01 will provide v2 devices > only, kernel 3.11 is not going to recognize any of them. > > What will happen in reality, though, is that the implementation of the > Linux v1/v2 driver will pre-date *any* v2 device by far. First > implementation of v1 devices appeared almost 2 years after the driver > appeared. It will take year for people to upgrade to v2, and probably > only after they experience problems with page-based addressing mode. > > I think I can live with this. Yes, this makes sense. In particular, MMIO doesn't have any users you don't control at this point. I expect it to be less than 2 years to get into qemu, but there'll be no compelling reason to use v2 devices for at least that long. Cheers, Rusty. -- 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
