Re: [Qemu-devel] [libvirt] ARM KVM GICv3 Support

[Peter Maydell]

On 2 February 2016 at 14:04, Andrew Jones <address@hidden> wrote:
> I agree we should have a good argument to justify messing with it, but
> until we start versioning mach-virt, then I don't think anybody should
> depend on mach-virt command lines working everywhere. Every time we add
> a new property, and a user adds it to their command line, then they've
> just broken that command line for older QEMU. Yes, I know the upgrade
> path is a bit different, but still... Anyway, properties are changeable
> with versioned machines.

Clearly command lines that use options added in newer QEMU won't
work on older QEMU, but we do make a serious effort to continue
to support older commandlines on newer QEMU, even if there is no
versioned migration support. Upgrading QEMU and expecting your old
configs to keep working is a reasonable user expectation.

thanks
-- PMM