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

[Sebastian Ott]

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;

which could also move above the other tests.

Sebastian