Re: [PATCH v3 03/17] KVM: x86/pmu: Introduce the ctrl_mask value for fixed counter

[Peter Zijlstra]

On Mon, Jan 04, 2021 at 09:15:28PM +0800, Like Xu wrote:
> @@ -327,6 +328,7 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
>  	pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
>  	pmu->version = 0;
>  	pmu->reserved_bits = 0xffffffff00200000ull;
> +	pmu->fixed_ctr_ctrl_mask = ~0ull;

All 1s

>  
>  	entry = kvm_find_cpuid_entry(vcpu, 0xa, 0);
>  	if (!entry)
> @@ -358,6 +360,9 @@ 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_mask |= (0xbull << (i * 4));

With some extra 1s on top

> +	pmu->fixed_ctr_ctrl_mask = ~pmu->fixed_ctr_ctrl_mask;

Inverted is all 0s, always.

>  	pmu->global_ctrl = ((1ull << pmu->nr_arch_gp_counters) - 1) |
>  		(((1ull << pmu->nr_arch_fixed_counters) - 1) << INTEL_PMC_IDX_FIXED);
>  	pmu->global_ctrl_mask = ~pmu->global_ctrl;
> -- 
> 2.29.2
>