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

[Michael S. Tsirkin]

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.

> > In fact, keeping this support around forces correct use of
> > posix APIs such as e.g. PRIx64 which makes the code base
> > more future-proof.
> 
> If you're concerned about PRIx64 and friends: We still continue to do
> compile testing with 32-bit MIPS cross-compilers and Windows 32-bit
> cross-compilers for now. The only thing we'd lose is the 32-bit "make check"
> run in the CI.
> 
>  Thomas

Yes - fundamentally 32 bit does not seem that different from e.g.
windows builds - we presumably support these but AFAIK CI does not
test these.


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MST