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

Peter Zijlstra
2021-01-13T18:09:56Z

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
>