Re: [PATCH 1/2] docs/about: Deprecate 32-bit x86 hosts and qemu-system-i386

["Michael S. Tsirkin" <mst@xxxxxxxxxx>]

On Tue, Feb 28, 2023 at 09:40:49AM +0000, Daniel P. Berrangé wrote:
> On Tue, Feb 28, 2023 at 10:14:52AM +0100, Thomas Huth wrote:
> > On 28/02/2023 10.03, Michael S. Tsirkin wrote:
> > > On Tue, Feb 28, 2023 at 08:59:52AM +0000, Daniel P. Berrangé wrote:
> > > > On Tue, Feb 28, 2023 at 03:19:20AM -0500, Michael S. Tsirkin wrote:
> > > > > On Tue, Feb 28, 2023 at 08:49:09AM +0100, Thomas Huth wrote:
> > > > > > On 27/02/2023 21.12, Michael S. Tsirkin wrote:
> > > > > > > On Mon, Feb 27, 2023 at 11:50:07AM +0000, Daniel P. Berrangé 
> > > > > > > wrote:
> > > > > > > > I feel like we should have separate deprecation entries for the
> > > > > > > > i686 host support, and for qemu-system-i386 emulator binary, as
> > > > > > > > although they're related they are independant features with
> > > > > > > > differing impact. eg removing qemu-system-i386 affects all
> > > > > > > > host architectures, not merely 32-bit x86 host, so I think we
> > > > > > > > can explain the impact more clearly if we separate them.
> > > > > > > 
> > > > > > > Removing qemu-system-i386 seems ok to me - I think 
> > > > > > > qemu-system-x86_64 is
> > > > > > > a superset.
> > > > > > > 
> > > > > > > Removing support for building on 32 bit systems seems like a pity 
> > > > > > > - it's
> > > > > > > one of a small number of ways to run 64 bit binaries on 32 bit 
> > > > > > > systems,
> > > > > > > and the maintainance overhead is quite small.
> > > > > > 
> > > > > > Note: We're talking about 32-bit *x86* hosts here. Do you really 
> > > > > > think that
> > > > > > someone is still using QEMU usermode emulation
> > > > > > to run 64-bit binaries on a 32-bit x86 host?? ... If so, I'd be 
> > > > > > very surprised!
> > > > > 
> > > > > I don't know - why x86 specifically? One can build a 32 bit binary on 
> > > > > any host.
> > > > > I think 32 bit x86 environments are just more common in the cloud.
> > > > 
> > > > Can you point to anything that backs up that assertion. Clouds I've
> > > > seen always give you a 64-bit environment, and many OS no longer
> > > > even ship 32-bit installable media.
> > > 
> > > Sorry about being unclear. I meant that it seems easier to run CI in the
> > > cloud in a 32 bit x64 environment than get a 32 bit ARM environment.
> > 
> > It's still doable ... but for how much longer? We're currently depending on
> > Fedora, but they also slowly drop more and more support for this
> > environment, see e.g.:
> 
> FWIW, we should cull our fedora-i386-cross.docker dockerfile and
> replace it with a debian i686 dockerfile generated by lcitool.
> There's no compelling reason why i686 should be different from
> all our other cross builds which are based on Debian. The Debian
> lcitool generated container would have access to a wider range
> of deps than our hand written Fedora one.
> 
> >  https://www.theregister.com/2022/03/10/fedora_inches_closer_to_dropping/
> 
> With regards,
> Daniel

... and is closer to where 32 bit is likely to be deployed which is
systems like e.g. raspberry pi os which until recently was only
32 bit.

-- 
MST