From: Paolo Bonzini <pbonzini@redhat.com>
To: Like Xu <like.xu@linux.intel.com>,
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>
Cc: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>,
ak@linux.intel.com, wei.w.wang@intel.com, kan.liang@intel.com,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [RESEND v13 10/10] KVM: vmx/pmu: Release guest LBR event via lazy release mechanism
Date: Tue, 26 Jan 2021 10:33:09 +0100 [thread overview]
Message-ID: <310d674c-44e7-7b46-064f-7cb88c456d0f@redhat.com> (raw)
In-Reply-To: <20210108013704.134985-11-like.xu@linux.intel.com>
On 08/01/21 02:37, Like Xu wrote:
> The vPMU uses GUEST_LBR_IN_USE_IDX (bit 58) in 'pmu->pmc_in_use' to
> indicate whether a guest LBR event is still needed by the vcpu. If the
> vcpu no longer accesses LBR related registers within a scheduling time
> slice, and the enable bit of LBR has been unset, vPMU will treat the
> guest LBR event as a bland event of a vPMC counter and release it
> as usual. Also, the pass-through state of LBR records msrs is cancelled.
>
> Signed-off-by: Like Xu <like.xu@linux.intel.com>
> Reviewed-by: Andi Kleen <ak@linux.intel.com>
> ---
> arch/x86/kvm/pmu.c | 7 +++++++
> arch/x86/kvm/pmu.h | 4 ++++
> arch/x86/kvm/vmx/pmu_intel.c | 17 ++++++++++++++++-
> 3 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 405890c723a1..e7c72eea07d4 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -463,6 +463,7 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
> struct kvm_pmc *pmc = NULL;
> DECLARE_BITMAP(bitmask, X86_PMC_IDX_MAX);
> int i;
> + bool extra_cleanup = false;
>
> pmu->need_cleanup = false;
>
> @@ -474,8 +475,14 @@ void kvm_pmu_cleanup(struct kvm_vcpu *vcpu)
>
> if (pmc && pmc->perf_event && !pmc_speculative_in_use(pmc))
> pmc_stop_counter(pmc);
> +
> + if (i == INTEL_GUEST_LBR_INUSE)
> + extra_cleanup = true;
> }
>
> + if (extra_cleanup && kvm_x86_ops.pmu_ops->cleanup)
> + kvm_x86_ops.pmu_ops->cleanup(vcpu);
> +
You can call this function always, it's cleaner than hardcoding
INTEL_GUEST_LBR_INUSE.
You can also use INTEL_PMC_IDX_FIXED_VLBR directly instead of
INTEL_GUEST_LBR_INUSE.
Paolo
next prev parent reply other threads:[~2021-01-26 14:56 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 1:36 [RESEND v13 00/10] KVM: x86/pmu: Guest Last Branch Recording Enabling Like Xu
2021-01-08 1:36 ` [RESEND v13 01/10] KVM: x86: Move common set/get handler of MSR_IA32_DEBUGCTLMSR to VMX Like Xu
2021-01-26 9:25 ` Paolo Bonzini
2021-01-08 1:36 ` [RESEND v13 02/10] KVM: x86/vmx: Make vmx_set_intercept_for_msr() non-static Like Xu
2021-01-08 1:36 ` [RESEND v13 03/10] KVM: x86/pmu: Use IA32_PERF_CAPABILITIES to adjust features visibility Like Xu
2021-01-26 9:42 ` Paolo Bonzini
2021-01-27 6:04 ` Like Xu
2021-01-27 9:48 ` Paolo Bonzini
2021-02-01 5:28 ` Like Xu
2021-01-08 1:36 ` [RESEND v13 04/10] KVM: vmx/pmu: Clear PMU_CAP_LBR_FMT when guest LBR is disabled Like Xu
2021-01-08 1:36 ` [RESEND v13 05/10] KVM: vmx/pmu: Create a guest LBR event when vcpu sets DEBUGCTLMSR_LBR Like Xu
2021-01-08 1:37 ` [RESEND v13 06/10] KVM: vmx/pmu: Pass-through LBR msrs when the guest LBR event is ACTIVE Like Xu
2021-01-08 1:37 ` [RESEND v13 07/10] KVM: vmx/pmu: Reduce the overhead of LBR pass-through or cancellation Like Xu
2021-01-26 9:27 ` Paolo Bonzini
2021-01-08 1:37 ` [RESEND v13 08/10] KVM: vmx/pmu: Emulate legacy freezing LBRs on virtual PMI Like Xu
2021-01-08 1:37 ` [RESEND v13 09/10] KVM: vmx/pmu: Expose LBR_FMT in the MSR_IA32_PERF_CAPABILITIES Like Xu
2021-01-26 9:30 ` Paolo Bonzini
2021-01-27 5:45 ` Xu, Like
2021-01-27 9:49 ` Paolo Bonzini
2021-01-08 1:37 ` [RESEND v13 10/10] KVM: vmx/pmu: Release guest LBR event via lazy release mechanism Like Xu
2021-01-26 9:33 ` Paolo Bonzini [this message]
2021-01-15 8:19 ` [RESEND v13 00/10] KVM: x86/pmu: Guest Last Branch Recording Enabling Alex Shi
2021-01-15 8:51 ` Xu, Like
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