Re: [PATCH v6 4/8] kvm: x86: Emulate split-lock access as a write in emulator

[Xiaoyao Li]

On 3/25/2020 8:00 AM, Thomas Gleixner wrote:
> Xiaoyao Li <xiaoyao.li@xxxxxxxxx> writes:
> >   
> > +bool split_lock_detect_on(void)
> > +{
> > +	return sld_state != sld_off;
> > +}
> > +EXPORT_SYMBOL_GPL(split_lock_detect_on);
>
> 1) You export this function here
>
> 2) You change that in one of the next patches to something else
>
> 3) According to patch 1/8 X86_FEATURE_SPLIT_LOCK_DETECT is not set when
>     sld_state == sld_off. FYI, I did that on purpose.
>
> AFAICT #1 and #2 are just historical leftovers of your previous patch
> series and the extra step was just adding more changed lines per patch
> for no value.
>
> #3 changed the detection mechanism and at the same time the semantics of
> the feature flag.
>
> So what's the point of this exercise?

Right. In this series, setting X86_FEATURE_SPLIT_LOCK_DETECT flag means 
SLD is turned on. Need to remove split_lock_detect_on(). Thanks for 
pointing out this.

> Thanks,
>
>          tglx