Re: [PATCH] docs/about: Automatically deprecate versioned machine types older than 6 years

[Cédric Le Goater]

On 4/30/24 11:45, Daniel P. Berrangé wrote:
> On Tue, Apr 30, 2024 at 08:45:29AM +0200, Thomas Huth wrote:
> > Old machine types often have bugs or work-arounds that affect our
> > possibilities to move forward with the QEMU code base (see for example
> > https://gitlab.com/qemu-project/qemu/-/issues/2213 for a bug that likely
> > cannot be fixed without breaking live migration with old machine types,
> > or https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg04516.html or
> > commit ea985d235b86). So instead of going through the process of manually
> > deprecating old machine types again and again, let's rather add an entry
> > that can stay, which declares that machine types older than 6 years are
> > considered as deprecated automatically. Six years should be sufficient to
> > support the release cycles of most Linux distributions.
>
> If anyone thinks 6 years is not very long, consider that this implies
> QEMU will be maintaining *18* versions for each versioned machine type.
>
> So across aarch64 'virt', x86 'pc' & 'q35', ppc 'spapr', s390x 'ccw',
> and m68k 'virt', that's upto 108 machines we're keeping ABI preserved
> for in the worst case...

We will probably have RISC-V machines to support also. Anyhow, 6 years
looks good to me.

Thanks,

C.