Re: [PATCH 2/3] x86/split_lock: Bits in IA32_CORE_CAPABILITIES are not architectural

[Luck, Tony]

On Fri, Apr 17, 2020 at 12:04:36PM +0200, Thomas Gleixner wrote:
> Tony Luck <tony.luck@xxxxxxxxx> writes:
> > +	m = x86_match_cpu(split_lock_cpu_ids);
> > +	if (!m)
> > +		return;
> > +
> > +	if (m->driver_data && cpu_has(c, X86_FEATURE_CORE_CAPABILITIES))
> > {
> 
> This condition results in the following:
> 
>     driver_data     MSR_CORE_CAPS	 MSR_CORE_CAPS_SLD	SLD available
> 
> 1       0             Don't care          Don't care               Y
> 2       1                N                Don't care               Y
> 3       1                Y                    Y                    Y
> 4       1                Y                    N                    N
> 
> #2 does not make any sense to me.

Nor to me :-(

I got too clever trying to combine tests.

New version taking cases one at a time so my "stuck inside the
house for six weeks now" brain can follow the steps.

-Tony