Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge

[Peter Zijlstra <peterz@infradead.org>]

On Fri, 2012-06-08 at 15:51 +0200, Borislav Petkov wrote:
> 
> In these cases, you already have PEBS fixed but since you're not loading
> any ucode, you won't run intel_snb_verify_ucode().
> 
> So, you want to check for PEBS twice (and for all other features fixed
> by ucode and tested for earlier than the ucode loader, for that matter):
> 
> * once when perf inits
> 
> * twice, a bit later when the ucode loader has loaded something from
> userspace and the notifier corrects it. 


>  static __init void intel_sandybridge_quirk(void)
>  {
> +       intel_snb_verify_ucode();
> +       /*
> +        * we're still single threaded, so while there's a hole here,
> +        * you can't trigger it.
> +        */
> +       microcode_notifier(intel_snb_ucode_notifier);
>  }

Like that you mean?