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

On Mon, Jan 04, 2021 at 09:15:28PM +0800, Like Xu wrote:

quoted

@@ -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

quoted

  
  	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.

quoted

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

Inverted is all 0s, always.

quoted

  	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