Re: [Xen-devel] [PATCH] perf: Check all MSRs before passing hw check

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.03.13 at 13:20, George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote:
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -182,6 +182,7 @@ static bool check_hw_exists(void)
>  {
>       u64 val, val_new = ~0;
>       int i, reg, ret = 0;
> +     int bios_fail = 0;
>  
>       /*
>        * Check to see if the BIOS enabled any of the counters, if so
> @@ -193,7 +194,7 @@ static bool check_hw_exists(void)
>               if (ret)
>                       goto msr_fail;
>               if (val & ARCH_PERFMON_EVENTSEL_ENABLE)
> -                     goto bios_fail;
> +                     bios_fail = 1;
>       }
>  
>       if (x86_pmu.num_counters_fixed) {
> @@ -203,7 +204,7 @@ static bool check_hw_exists(void)
>                       goto msr_fail;
>               for (i = 0; i < x86_pmu.num_counters_fixed; i++) {
>                       if (val & (0x03 << i*4))
> -                             goto bios_fail;
> +                             bios_fail = 1;
>               }
>       }
>  
> @@ -221,14 +222,13 @@ static bool check_hw_exists(void)
>       if (ret || val != val_new)
>               goto msr_fail;
>  
> -     return true;
> -
> -bios_fail:
> -     /*
> -      * We still allow the PMU driver to operate:
> -      */
> -     printk(KERN_CONT "Broken BIOS detected, complain to your hardware 
> vendor.\n");
> -     printk(KERN_ERR FW_BUG "the BIOS has corrupted hw-PMU resources (MSR %x 
> is %Lx)\n", reg, val);
> +     if (bios_fail) {
> +             /*
> +              * We still allow the PMU driver to operate:
> +              */
> +             printk(KERN_CONT "Broken BIOS detected, complain to your 
> hardware vendor.\n");
> +             printk(KERN_ERR FW_BUG "the BIOS has corrupted hw-PMU resources 
> (MSR %x is %Lx)\n", reg, val);

The values being printed here are not meaningful anymore with this
patch.

Jan

> +     }
>  
>       return true;
>  



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