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From: Peter Zijlstra <peterz@infradead.org>
To: Like Xu <like.xu@linux.intel.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	eranian@google.com, andi@firstfloor.org,
	kan.liang@linux.intel.com, wei.w.wang@intel.com,
	Wanpeng Li <wanpengli@tencent.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v4 06/16] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter
Date: Wed, 7 Apr 2021 10:40:00 +0200	[thread overview]
Message-ID: <YG1v4KFCPSoKcoyd@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210329054137.120994-7-like.xu@linux.intel.com>

On Mon, Mar 29, 2021 at 01:41:27PM +0800, Like Xu wrote:

> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 827886c12c16..3509b18478b9 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -74,11 +74,20 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
>  {
>  	struct kvm_pmc *pmc = perf_event->overflow_handler_context;
>  	struct kvm_pmu *pmu = pmc_to_pmu(pmc);
> +	bool skip_pmi = false;
>  
>  	if (!test_and_set_bit(pmc->idx, pmu->reprogram_pmi)) {
> -		__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
> +		if (perf_event->attr.precise_ip) {
> +			/* Indicate PEBS overflow PMI to guest. */
> +			skip_pmi = test_and_set_bit(GLOBAL_STATUS_BUFFER_OVF_BIT,
> +				(unsigned long *)&pmu->global_status);

Is there actual concurrency here, or did you forget to type __?

And in case you're using vim, use something like: set cino=(0:0

> +		} else
> +			__set_bit(pmc->idx, (unsigned long *)&pmu->global_status);
>  		kvm_make_request(KVM_REQ_PMU, pmc->vcpu);
>  
> +		if (skip_pmi)
> +			return;
> +
>  		/*
>  		 * Inject PMI. If vcpu was in a guest mode during NMI PMI
>  		 * can be ejected on a guest mode re-entry. Otherwise we can't

  reply	other threads:[~2021-04-07  8:41 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-29  5:41 [PATCH v4 00/16] KVM: x86/pmu: Add basic support to enable Guest PEBS via DS Like Xu
2021-03-29  5:41 ` [PATCH v4 01/16] perf/x86/intel: Add x86_pmu.pebs_vmx for Ice Lake Servers Like Xu
2021-04-06  3:24   ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-06  5:14     ` Xu, Like
2021-04-08  1:40       ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-09  8:33       ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-09  8:46         ` Like Xu
2021-04-12 11:26           ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-12 15:25             ` Andi Kleen
2021-04-14 14:10               ` Liuxiangdong
2021-04-14 14:49           ` Liuxiangdong
2021-04-15  1:38             ` Xu, Like
2021-04-15  2:49               ` Liuxiangdong
2021-04-15  3:23                 ` Like Xu
2021-04-06 12:47     ` Andi Kleen
2021-04-07  3:05       ` Liuxiangdong (Aven, Cloud Infrastructure Service Product Dept.)
2021-04-07 14:32         ` Andi Kleen
2021-03-29  5:41 ` [PATCH v4 02/16] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Like Xu
2021-04-06 16:22   ` Peter Zijlstra
2021-04-07  0:47     ` Xu, Like
2021-03-29  5:41 ` [PATCH v4 03/16] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Like Xu
2021-03-29  5:41 ` [PATCH v4 04/16] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Like Xu
2021-03-29  5:41 ` [PATCH v4 05/16] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Like Xu
2021-03-29  5:41 ` [PATCH v4 06/16] KVM: x86/pmu: Reprogram guest PEBS event to emulate guest PEBS counter Like Xu
2021-04-07  8:40   ` Peter Zijlstra [this message]
2021-03-29  5:41 ` [PATCH v4 07/16] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Like Xu
2021-04-07  8:56   ` Peter Zijlstra
2021-04-07 15:25   ` Peter Zijlstra
2021-03-29  5:41 ` [PATCH v4 08/16] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to manage guest DS buffer Like Xu
2021-04-07 15:39   ` Peter Zijlstra
2021-04-08  5:39     ` Xu, Like
2021-04-08  7:52       ` Peter Zijlstra
2021-04-08  8:44         ` Xu, Like
2021-04-09  7:07         ` Xu, Like
2021-04-09  7:59           ` Peter Zijlstra
2021-04-09  8:30             ` Xu, Like
2021-03-29  5:41 ` [PATCH v4 09/16] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Like Xu
2021-04-07 15:40   ` Peter Zijlstra
2021-03-29  5:41 ` [PATCH v4 10/16] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Like Xu
2021-03-29  5:41 ` [PATCH v4 11/16] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Like Xu
2021-03-29  5:41 ` [PATCH v4 12/16] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Like Xu
2021-03-29  5:41 ` [PATCH v4 13/16] KVM: x86/pmu: Disable guest PEBS before vm-entry in two cases Like Xu
2021-03-29  5:41 ` [PATCH v4 14/16] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Like Xu
2021-03-29  5:41 ` [PATCH v4 15/16] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Like Xu
2021-03-29  5:41 ` [PATCH v4 16/16] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Like Xu
2021-04-06  3:19 ` [PATCH v4 00/16] KVM: x86/pmu: Add basic support to enable Guest PEBS via DS Xu, Like

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