On Wed, Apr 13, 2016 at 06:17:29PM +0200, Markus Armbruster wrote: > "Michael S. Tsirkin" <m...@redhat.com> writes: > > > On Wed, Apr 13, 2016 at 10:59:35AM +0200, Markus Armbruster wrote: > >> I have a hard time coming up with realistic unclean breakage. > > > > The issue is that Linux is now exposing fw cfg to userspace. > > So it's use is about to expand significantly. > > > > This is what I am trying to prevent: > > - in 2016, users build a guest using a path XXX outside opt. > > there's a warning on host, but it is not noticed. > > Amend: > > The guest treats path XXX as optional. > > > - in 2020, qemu starts using path XXX for internal purposes. > > - using guest from 2016 now breaks uncleanly on this new qemu > > Amend: > > when we're not specifying the optional path XXX with -fw_cfg. > > > since guest thinks it's talking to the external tool. > > Okay, that's a much more plausible scenario. The question remains > whether preventing it justifies the compat break and the additional > interface complexity.
there is no break as long as people follow the rules.
