Messages in this thread | | | Subject | Re: [RESEND v13 10/10] KVM: vmx/pmu: Release guest LBR event via lazy release mechanism | From | Paolo Bonzini <> | Date | Tue, 26 Jan 2021 10:33:09 +0100 |
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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
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