Re: [PATCH v3] arm/kvm: Enable support for KVM_ARM_VCPU_PMU_V3_FILTER

[Shaoqin Huang]

On 12/1/23 00:55, Sebastian Ott wrote:
> On Tue, 28 Nov 2023, Shaoqin Huang wrote:
> > +static void kvm_arm_pmu_filter_init(CPUState *cs)
> > +{
> > +    static bool pmu_filter_init = false;
> > +    struct kvm_pmu_event_filter filter;
> > +    struct kvm_device_attr attr = {
> > +        .group      = KVM_ARM_VCPU_PMU_V3_CTRL,
> > +        .attr       = KVM_ARM_VCPU_PMU_V3_FILTER,
> > +        .addr       = (uint64_t)&filter,
> > +    };
> > +    KVMState *kvm_state = cs->kvm_state;
> > +    char *tmp;
> > +    char *str, act;
> > +
> > +    if (!kvm_state->kvm_pmu_filter)
> > +        return;
> > +
> > +    if (kvm_vcpu_ioctl(cs, KVM_HAS_DEVICE_ATTR, attr)) {
> > +        error_report("The kernel doesn't support the pmu event 
> > filter!\n");
> > +        abort();
> > +    }
> > +
> > +    /* The filter only needs to be initialized for 1 vcpu. */
> > +    if (!pmu_filter_init)
> > +        pmu_filter_init = true;
>
> Imho this is missing an else to bail out. Or the shorter version
>
>      if (pmu_filter_init)
>          return;
>
>      pmu_filter_init = true;

Yes. This is what I want to do. Thanks for fixing it.

> which could also move above the other tests.
>
> Sebastian

--
Shaoqin