Re: [PATCH] x86: print microcode revision on PEBs errors

[Joe Perches <joe@perches.com>]

On Wed, 2013-10-30 at 21:31 +0200, Michael S. Tsirkin wrote:
> On Sandy bridge CPUs with old microcode, PEBs
> fails and suggests a microcode update.
> Print out the required and the actual revision to
> make it easier to figure out what's wrong.
[]
> diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
[]
> @@ -2105,6 +2105,8 @@ static int intel_snb_pebs_broken(int cpu)
>  		}
>  	}
>  
> +	pr_info("PEBS checking: microcode 0x%x min legal 0x%x\n",
> +		cpu_data(cpu).microcode, rev);

Maybe only emit this with microcode < rev
otherwise it gets emitted once for each online cpu

>  	return (cpu_data(cpu).microcode < rev);
>  }
>