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From: Peter Zijlstra <peterz@infradead.org>
To: Zhu Lingshan <lingshan.zhu@intel.com>
Cc: pbonzini@redhat.com, bp@alien8.de, seanjc@google.com,
	vkuznets@redhat.com, wanpengli@tencent.com, jmattson@google.com,
	joro@8bytes.org, weijiang.yang@intel.com,
	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, like.xu.linux@gmail.com,
	Like Xu <like.xu@linux.intel.com>
Subject: Re: [PATCH V7 15/18] KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations
Date: Fri, 2 Jul 2021 14:46:48 +0200	[thread overview]
Message-ID: <YN8KuNOOm1UBBsGJ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20210622094306.8336-16-lingshan.zhu@intel.com>

On Tue, Jun 22, 2021 at 05:43:03PM +0800, Zhu Lingshan wrote:
> diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
> index 22386c1a32b4..8bf494f8af3e 100644
> --- a/arch/x86/events/intel/core.c
> +++ b/arch/x86/events/intel/core.c
> @@ -3970,8 +3970,15 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr, void *data)
>  		.guest = pebs_mask & ~cpuc->intel_ctrl_host_mask,
>  	};
>  
> -	/* Set hw GLOBAL_CTRL bits for PEBS counter when it runs for guest */
> -	arr[0].guest |= arr[*nr].guest;
> +	if (arr[*nr].host) {
> +		/* Disable guest PEBS if host PEBS is enabled. */
> +		arr[*nr].guest = 0;
> +	} else {
> +		/* Disable guest PEBS for cross-mapped PEBS counters. */
> +		arr[*nr].guest &= ~pmu->host_cross_mapped_mask;
> +		/* Set hw GLOBAL_CTRL bits for PEBS counter when it runs for guest */
> +		arr[0].guest |= arr[*nr].guest;
> +	}

Not saying I disagree, but is there any way for the guest to figure out
why things aren't working? Is there like a guest log we can dump
something in?

> +void intel_pmu_cross_mapped_check(struct kvm_pmu *pmu)
> +{
> +	struct kvm_pmc *pmc = NULL;
> +	int bit;
> +
> +	for_each_set_bit(bit, (unsigned long *)&pmu->global_ctrl,
> +			 X86_PMC_IDX_MAX) {
> +		pmc = kvm_x86_ops.pmu_ops->pmc_idx_to_pmc(pmu, bit);
> +
> +		if (!pmc || !pmc_speculative_in_use(pmc) ||
> +		    !pmc_is_enabled(pmc))
> +			continue;
> +
> +		if (pmc->perf_event && (pmc->idx != pmc->perf_event->hw.idx))
> +			pmu->host_cross_mapped_mask |=
> +				BIT_ULL(pmc->perf_event->hw.idx);

{ } again.

> +	}
> +}

  reply	other threads:[~2021-07-02 12:47 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-22  9:42 [PATCH V7 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 01/18] perf/core: Use static_call to optimize perf_guest_info_callbacks Zhu Lingshan
2021-07-02 11:22   ` Peter Zijlstra
2021-07-02 16:00     ` Joe Perches
2021-07-02 16:19       ` Peter Zijlstra
2021-07-02 16:42         ` Joe Perches
2021-07-02 16:38       ` Mark Rutland
2021-07-02 16:56         ` Joe Perches
2021-07-08  8:53     ` Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 02/18] perf/x86/intel: Add EPT-Friendly PEBS for Ice Lake Server Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 03/18] perf/x86/intel: Handle guest PEBS overflow PMI for KVM guest Zhu Lingshan
2021-07-02 11:28   ` Peter Zijlstra
2021-07-08 13:39     ` Zhu, Lingshan
2021-06-22  9:42 ` [PATCH V7 04/18] perf/x86/core: Pass "struct kvm_pmu *" to determine the guest values Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 05/18] KVM: x86/pmu: Set MSR_IA32_MISC_ENABLE_EMON bit when vPMU is enabled Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 06/18] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 07/18] x86/perf/core: Add pebs_capable to store valid PEBS_COUNTER_MASK value Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 08/18] KVM: x86/pmu: Add IA32_PEBS_ENABLE MSR emulation for extended PEBS Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 09/18] KVM: x86/pmu: Reprogram PEBS event to emulate guest PEBS counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 10/18] KVM: x86/pmu: Adjust precise_ip to emulate Ice Lake guest PDIR counter Zhu Lingshan
2021-06-22  9:42 ` [PATCH V7 11/18] KVM: x86/pmu: Add IA32_DS_AREA MSR emulation to support guest DS Zhu Lingshan
2021-07-02 11:52   ` Peter Zijlstra
2021-07-08  8:52     ` Zhu, Lingshan
2021-06-22  9:43 ` [PATCH V7 12/18] KVM: x86/pmu: Add PEBS_DATA_CFG MSR emulation to support adaptive PEBS Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 13/18] KVM: x86: Set PEBS_UNAVAIL in IA32_MISC_ENABLE when PEBS is enabled Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 14/18] KVM: x86/pmu: Move pmc_speculative_in_use() to arch/x86/kvm/pmu.h Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 15/18] KVM: x86/pmu: Disable guest PEBS temporarily in two rare situations Zhu Lingshan
2021-07-02 12:46   ` Peter Zijlstra [this message]
2021-07-08  8:52     ` Zhu, Lingshan
2021-06-22  9:43 ` [PATCH V7 16/18] KVM: x86/pmu: Add kvm_pmu_cap to optimize perf_get_x86_pmu_capability Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 17/18] KVM: x86/cpuid: Refactor host/guest CPU model consistency check Zhu Lingshan
2021-06-22  9:43 ` [PATCH V7 18/18] KVM: x86/pmu: Expose CPUIDs feature bits PDCM, DS, DTES64 Zhu Lingshan
2021-06-25  9:40 ` [PATCH V7 00/18] KVM: x86/pmu: Add *basic* support to enable guest PEBS via DS Liuxiangdong
2021-06-25  9:46   ` Zhu, Lingshan
2021-06-28  7:49     ` Wang, Wei W
2021-06-28  7:53       ` Zhu, Lingshan
2021-07-02 12:49 ` Peter Zijlstra
2021-07-12  1:37 ` Liuxiangdong
2021-07-12 10:34   ` Like Xu

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