On 12.07.2017 17:04, Daniel P. Berrange wrote: > On Wed, Jul 12, 2017 at 10:22:33AM +0200, Thomas Huth wrote: >> We don't want to carry along old machine types forever. If we are able to >> remove the pc machines up to 0.13 one day for example, this would allow >> us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM >> BARs directly to low memory). Everything up to pc-1.2 is also known to >> have issues with migration. So let's start with a deprecation message >> for the old machine types so that the (hopefully) few users of these old >> systems start switching over to newer machine types instead. > > I think we must document & agree on our support policy for machine > types, before we start marking them as deprecated. eg please consider > the following document before accepting this deprecation patch: > > https://lists.gnu.org/archive/html/qemu-devel/2017-07/msg00652.html > > Note in that proposal there, I say we do *not* go through trouble of > explicitly marking machines as deprecated. We just document upfront > the intended lifecycle and then delete them when it is done. > > Just use deprecation warnings for things where there is no predictable > lifecycle upfront.
I'm still not 100% sure whether that auto-deprecation of machine types is such a good idea ... since we might need to maintain machines in downstream a little bit longer than specified there, it might be better to rather deprecate them manually from time to time. Anyway, concerning my patch - I'll stop here and won't send another version. There is too much bikeshed painting going on in this area for my taste, and since I'm rather a powerpc / s390x guy, I'm also fine if the pc-0.x machines stay around forever. If somebody else wants to push this topic instead, feel free to do so. Thomas
