linux-kernel - Re: [PATCH] KVM: x86/pmu: Add a helper to enable bits in FIXED_CTR

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Message-ID: <e41fd2bc-26f0-4811-927b-3e94d13d5dac@linux.intel.com>
Date: Tue, 11 Jun 2024 09:45:44 +0800
From: "Mi, Dapeng" <dapeng1.mi@...ux.intel.com>
To: Sean Christopherson <seanjc@...gle.com>,
 Paolo Bonzini <pbonzini@...hat.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] KVM: x86/pmu: Add a helper to enable bits in
 FIXED_CTR_CTRL


On 6/8/2024 8:08 AM, Sean Christopherson wrote:
> Add a helper, intel_pmu_enable_fixed_counter_bits(), to dedup code that
> enables fixed counter bits, i.e. when KVM clears bits in the reserved mask
> used to detect invalid MSR_CORE_PERF_FIXED_CTR_CTRL values.
>
> No functional change intended.
>
> Cc: Dapeng Mi <dapeng1.mi@...ux.intel.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/kvm/vmx/pmu_intel.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index e01c87981927..fb5cbd6cbeff 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -448,6 +448,14 @@ static __always_inline u64 intel_get_fixed_pmc_eventsel(unsigned int index)
>  	return eventsel;
>  }
>  
> +static void intel_pmu_enable_fixed_counter_bits(struct kvm_pmu *pmu, u64 bits)
> +{
> +	int i;
> +
> +	for (i = 0; i < pmu->nr_arch_fixed_counters; i++)
> +		pmu->fixed_ctr_ctrl_rsvd &= ~intel_fixed_bits_by_idx(i, bits);
> +}
> +
>  static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> @@ -457,7 +465,6 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
>  	union cpuid10_edx edx;
>  	u64 perf_capabilities;
>  	u64 counter_rsvd;
> -	int i;
>  
>  	memset(&lbr_desc->records, 0, sizeof(lbr_desc->records));
>  
> @@ -501,12 +508,9 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
>  			((u64)1 << edx.split.bit_width_fixed) - 1;
>  	}
>  
> -	for (i = 0; i < pmu->nr_arch_fixed_counters; i++)
> -		pmu->fixed_ctr_ctrl_rsvd &=
> -			 ~intel_fixed_bits_by_idx(i,
> -						  INTEL_FIXED_0_KERNEL |
> -						  INTEL_FIXED_0_USER |
> -						  INTEL_FIXED_0_ENABLE_PMI);
> +	intel_pmu_enable_fixed_counter_bits(pmu, INTEL_FIXED_0_KERNEL |
> +						 INTEL_FIXED_0_USER |
> +						 INTEL_FIXED_0_ENABLE_PMI);
>  
>  	counter_rsvd = ~(((1ull << pmu->nr_arch_gp_counters) - 1) |
>  		(((1ull << pmu->nr_arch_fixed_counters) - 1) << KVM_FIXED_PMC_BASE_IDX));
> @@ -551,10 +555,8 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
>  		if (perf_capabilities & PERF_CAP_PEBS_BASELINE) {
>  			pmu->pebs_enable_rsvd = counter_rsvd;
>  			pmu->reserved_bits &= ~ICL_EVENTSEL_ADAPTIVE;
> -			for (i = 0; i < pmu->nr_arch_fixed_counters; i++)
> -				pmu->fixed_ctr_ctrl_rsvd &=
> -					~intel_fixed_bits_by_idx(i, ICL_FIXED_0_ADAPTIVE);
>  			pmu->pebs_data_cfg_rsvd = ~0xff00000full;
> +			intel_pmu_enable_fixed_counter_bits(pmu, ICL_FIXED_0_ADAPTIVE);
>  		} else {
>  			pmu->pebs_enable_rsvd =
>  				~((1ull << pmu->nr_arch_gp_counters) - 1);
>
> base-commit: b9adc10edd4e14e66db4f7289a88fdbfa45ae7a8

Reviewed-by: Dapeng Mi <dapeng1.mi@...ux.intel.com>