Re: [PATCH 01/15] x86/split_lock: Add CONFIG and enumerate #AC exception for split locked access feature

[Fenghua Yu]

On Tue, May 15, 2018 at 08:36:35AM -0700, Dave Hansen wrote:
> On 05/14/2018 11:52 AM, Fenghua Yu wrote:
> > +#include <linux/printk.h>
> > +#include <asm/msr.h>
> > +
> > +static bool split_lock_ac_supported;
> 
> Was there a reason not to use an X86_FEATURE* bit for this?

The feature is not enumerated in cpuid. It's detected by writing 1
to bit 29 in MSR 0x33.

So it can't fit in X86_FEATURE, right?

Thanks.

-Fenghua