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Date:   Mon, 17 May 2021 10:39:17 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Like Xu <like.xu@linux.intel.com>
Cc:     Paolo Bonzini <pbonzini@redhat.com>,
        Borislav Petkov <bp@alien8.de>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>, weijiang.yang@intel.com,
        Kan Liang <kan.liang@linux.intel.com>, ak@linux.intel.com,
        wei.w.wang@intel.com, eranian@google.com, liuxiangdong5@huawei.com,
        linux-kernel@vger.kernel.org, x86@kernel.org, kvm@vger.kernel.org
Subject: Re: [PATCH v6 07/16] KVM: x86/pmu: Reprogram PEBS event to emulate
 guest PEBS counter
Message-ID: <YKIrtdbXRcZSiohg@hirez.programming.kicks-ass.net>
References: <20210511024214.280733-1-like.xu@linux.intel.com>
 <20210511024214.280733-8-like.xu@linux.intel.com>
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On Tue, May 11, 2021 at 10:42:05AM +0800, Like Xu wrote:
> +	if (pebs) {
> +		/*
> +		 * The non-zero precision level of guest event makes the ordinary
> +		 * guest event becomes a guest PEBS event and triggers the host
> +		 * PEBS PMI handler to determine whether the PEBS overflow PMI
> +		 * comes from the host counters or the guest.
> +		 *
> +		 * For most PEBS hardware events, the difference in the software
> +		 * precision levels of guest and host PEBS events will not affect
> +		 * the accuracy of the PEBS profiling result, because the "event IP"
> +		 * in the PEBS record is calibrated on the guest side.
> +		 */
> +		attr.precise_ip = 1;
> +	}

You've just destroyed precdist, no?