Re: [PATCH v2 00/14] meson: Deprecate 32-bit host support

[Daniel P. Berrangé <berrange@xxxxxxxxxx>]

On Mon, Feb 03, 2025 at 02:43:05PM -0800, Stefano Stabellini wrote:
> +Xen maintainers
> 
> 
> On Mon, 3 Feb 2025, Richard Henderson wrote:
> > On 2/3/25 04:54, Paolo Bonzini wrote:
> > > On 2/3/25 04:18, Richard Henderson wrote:
> > > > v1: 20250128004254.33442-1-richard.henderson@xxxxxxxxxx
> > > > 
> > > > For v2, immediately disable 64-on-32 TCG.
> > > > 
> > > > I *suspect* that we should disable 64-on-32 for *all* accelerators.
> > > > The idea that an i686 binary on an x86_64 host may be used to spawn
> > > > an x86_64 guest via kvm is silly and a bit more than niche.
> > > 
> > > At least Xen used to be commonly used with 32-bit dom0, because it saved
> > > memory and dom0 would map in guest buffers as needed.  I'm not sure how
> > > common that is these days, perhaps Stefano knows.
> > 
> > As a data-point, debian does not ship libxen-dev for i686.
> > We cannot build-test this configuration at all.
> > 
> > I can build-test Xen for armhf, and I guess it would use i386-softmmu; it's
> > unclear whether x86_64-softmmu and aarch64-softmmu are relevant or useful 
> > for
> > an armhf host, or as an armhf binary running on an aarch64 host.
> 
> 
> On the Xen side, there are two different use cases: x86 32-bit and ARM
> 32-bit.  
> 
> For x86 32-bit, while it was a very important use case in the past, I
> believe it is far less so now. I will let the x86 maintainers comment on
> how important it is today.

If the Xen project needs an excuse to justify stopping 32-bit host
support, QEMU would be happy to act as the excuse :-)

With regards,
Daniel
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