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