Re: [PATCH 0/5] Reinstate ability to use Qemu on pre-SSE4.1 x86 hosts

[Daniel P . Berrangé]

On Wed, Jun 12, 2024 at 06:40:09PM +0300, Alexander Monakov wrote:
> 
> On Wed, 12 Jun 2024, Daniel P. Berrangé wrote:
> 
> > I learnt that FESCo approved a surprisingly loose rule saying
> > 
> >   "Libraries packaged in Fedora may require ISA extensions,
> >    however any packaged application must not crash on any
> >    officially supported architecture, either by providing
> >    a generic fallback implementation OR by cleanly exiting
> >    when the requisite hardware support is unavailable."
> > 
> > This might suggest we could put a runtime feature check in main(),
> > print a warning and then exit(1), however, QEMU has alot of code
> > that is triggered from ELF constructors. If we're building the
> > entire of QEMU codebase with extra features enabled, I worry that
> > the constructors could potentially cause a illegal instruction
> > crash before main() runs ?
> 
> Are you literally suggesting to find a solution that satisfies the letter
> of Fedora rules, and not what's good for the spirit of a wider community.

I'm interested in exploring what the options are. Personally I still
think QEMU ought to maintain compat with the original x86_64 ABI, since
very few distros have moved to requiring -v2, but if that doesn't happen
I want to understand the implications for Fedora since that's where I'm
a maintainer.

With regards,
Daniel
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