linux-kernel - Re: [PATCH v2] perf/x86: Fix HO/GO counting with SVM disabled

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Date:	Wed, 29 Feb 2012 18:44:49 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Joerg Roedel <joerg.roedel@....com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org, joro@...tes.org,
	Ingo Molnar <mingo@...e.hu>, Avi Kivity <avi@...hat.com>,
	Stephane Eranian <eranian@...gle.com>,
	David Ahern <dsahern@...il.com>,
	Gleb Natapov <gleb@...hat.com>,
	Robert Richter <robert.richter@....com>
Subject: Re: [PATCH v2] perf/x86: Fix HO/GO counting with SVM disabled

On Wed, 2012-02-29 at 14:57 +0100, Joerg Roedel wrote:

> diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
> index 8944062..2c581b9 100644
> --- a/arch/x86/kernel/cpu/perf_event.h
> +++ b/arch/x86/kernel/cpu/perf_event.h
> @@ -148,6 +148,8 @@ struct cpu_hw_events {
>          * AMD specific bits
>          */
>         struct amd_nb           *amd_nb;
> +       /* Inverted mask of bits to clear in the perf_ctr ctrl registers */
> +       u64                     perf_ctr_virt_mask;
>  
>         void                            *kfree_on_online;
>  };
> @@ -417,9 +419,11 @@ void x86_pmu_disable_all(void);
>  static inline void __x86_pmu_enable_event(struct hw_perf_event *hwc,
>                                           u64 enable_mask)
>  {
> +       u64 disable_mask = __this_cpu_read(cpu_hw_events.perf_ctr_virt_mask);
> +
>         if (hwc->extra_reg.reg)
>                 wrmsrl(hwc->extra_reg.reg, hwc->extra_reg.config);
> -       wrmsrl(hwc->config_base, hwc->config | enable_mask);
> +       wrmsrl(hwc->config_base, (hwc->config | enable_mask) & ~disable_mask);
>  }

Its starting to look like we should kill this helper, the extra_reg muck
is Intel only and the disable_mask is AMD.



Queued it for now though.. 
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