While they haven't announced any of it in public, it does seem hard to believe they'd be migrating running applications. It's much more likely that they're targeting nx page sharing, you'd still have build the os for both isas, but it'd allow you to run many tasks on the low poer cores and only spin up the hot ones when the application required the performance or binary compatibility. Think more like switchable graphics than big.little, though the low power architecture would stay usable all the time.