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

[Xu, Like]

On 2021/1/14 2:06, Peter Zijlstra wrote:

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

You're right, I think it should be:

    pmu->fixed_ctr_ctrl_mask &= ~(0xbull << (i * 4));

w/o invertion and I will fix it in the next version.

+       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