[PATCH 0/2] Deprecate support for 32-bit x86 and arm hosts

[Daniel P. Berrangé]

On Tue, Feb 28, 2023 at 08:39:49AM +0100, Thomas Huth wrote:
> On 27/02/2023 19.38, Daniel P. Berrangé wrote:
> > On Mon, Feb 27, 2023 at 12:10:48PM +0100, Thomas Huth wrote:
> > > We're struggling quite badly with our CI minutes on the shared
> > > gitlab runners, so we urgently need to think of ways to cut down
> > > our supported build and target environments. qemu-system-i386 and
> > > qemu-system-arm are not really required anymore, since nobody uses
> > > KVM on the corresponding systems for production anymore, and the
> > > -x86_64 and -arch64 variants are a proper superset of those binaries.
> > > So it's time to deprecate them and the corresponding 32-bit host
> > > environments now.
> > > 
> > > This is a follow-up patch series from the previous discussion here:
> > > 
> > >   https://lore.kernel.org/qemu-devel/20230130114428.1297295-1-thuth@redhat.com/
> > > 
> > > where people still mentioned that there is still interest in certain
> > > support for 32-bit host hardware. But as far as I could see, there is
> > > no real need for 32-bit host support for system emulation on x86 and
> > > arm anymore, so it should be fine if we drop these host environments
> > > now (these are also the two architectures that contribute the most to
> > > the long test times in our CI, so we would benefit a lot by dropping
> > > those).
> > 
> > Your description here is a little ambiguous about what's being
> > proposed. When you say dropping 32-bit host support do you mean
> > just for the system emulator binaries, or for QEMU entirely ?
> 
> Just for system emulation. Some people said that user emulation still might
> be useful for some 32-bit environments.
> 
> > And when the deprecation period is passed, are you proposing
> > to actively prevent 32-bit builds, or merely stopping CI testing
> > and leave 32-bit builds still working if people want them ?
> 
> CI is the main pain point, so that's the most important thing. So whether we
> throw a warning or a hard error while configuring the build, I don't care
> too much.

If we're merely wanting to drop CI support, we can do that any time and
deprecation is not required/expected.  We should only be using deprecation
where we're explicitly intending that the code will cease to work.


With regards,
Daniel
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