On Sun, Dec 11, 2016 at 10:52:25PM +0000, Peter Maydell wrote: > On 11 December 2016 at 16:35, Christoffer Dall > <christoffer.d...@linaro.org> wrote: > > On Fri, Dec 09, 2016 at 04:30:20PM +0000, Peter Maydell wrote: > >> + * For backwards-compatibility, virt-2.8 and earlier will continue > >> + * to say these are edge-triggered, but later machines will report > >> + * the correct information. > >> */ > > > > Is this really necessary? > > It's being conservative -- from the guest's point of view > (any guest, not necessarily just Linux) "virt-2.8" should behave > like the "virt" machine in the 2.8 QEMU release, including bugs, > not providing newer devices, and so on. > > Andrew would be the expert on whether this is being unnecessarily > conservative in this specific case.
I agree that all DT and ACPI (we need the equivalent change to the GTDT) changes should require compatibility code. We should document a list of mach-virt change types that require machine version consideration somewhere. I can ask our migration experts to help me pull a list together. Thanks, drew
