int kvm_arm_pmu_v3_set_attr()

in kvm/pmu-emul.c [925:1016]

• 64 lines of code
• 22 McCabe index (conditional complexity)

int kvm_arm_pmu_v3_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
{
	if (!kvm_vcpu_has_pmu(vcpu))
		return -ENODEV;

	if (vcpu->arch.pmu.created)
		return -EBUSY;

	if (!vcpu->kvm->arch.pmuver)
		vcpu->kvm->arch.pmuver = kvm_pmu_probe_pmuver();

	if (vcpu->kvm->arch.pmuver == ID_AA64DFR0_PMUVER_IMP_DEF)
		return -ENODEV;

	switch (attr->attr) {
	case KVM_ARM_VCPU_PMU_V3_IRQ: {
		int __user *uaddr = (int __user *)(long)attr->addr;
		int irq;

		if (!irqchip_in_kernel(vcpu->kvm))
			return -EINVAL;

		if (get_user(irq, uaddr))
			return -EFAULT;

		/* The PMU overflow interrupt can be a PPI or a valid SPI. */
		if (!(irq_is_ppi(irq) || irq_is_spi(irq)))
			return -EINVAL;

		if (!pmu_irq_is_valid(vcpu->kvm, irq))
			return -EINVAL;

		if (kvm_arm_pmu_irq_initialized(vcpu))
			return -EBUSY;

		kvm_debug("Set kvm ARM PMU irq: %d\n", irq);
		vcpu->arch.pmu.irq_num = irq;
		return 0;
	}
	case KVM_ARM_VCPU_PMU_V3_FILTER: {
		struct kvm_pmu_event_filter __user *uaddr;
		struct kvm_pmu_event_filter filter;
		int nr_events;

		nr_events = kvm_pmu_event_mask(vcpu->kvm) + 1;

		uaddr = (struct kvm_pmu_event_filter __user *)(long)attr->addr;

		if (copy_from_user(&filter, uaddr, sizeof(filter)))
			return -EFAULT;

		if (((u32)filter.base_event + filter.nevents) > nr_events ||
		    (filter.action != KVM_PMU_EVENT_ALLOW &&
		     filter.action != KVM_PMU_EVENT_DENY))
			return -EINVAL;

		mutex_lock(&vcpu->kvm->lock);

		if (!vcpu->kvm->arch.pmu_filter) {
			vcpu->kvm->arch.pmu_filter = bitmap_alloc(nr_events, GFP_KERNEL_ACCOUNT);
			if (!vcpu->kvm->arch.pmu_filter) {
				mutex_unlock(&vcpu->kvm->lock);
				return -ENOMEM;
			}

			/*
			 * The default depends on the first applied filter.
			 * If it allows events, the default is to deny.
			 * Conversely, if the first filter denies a set of
			 * events, the default is to allow.
			 */
			if (filter.action == KVM_PMU_EVENT_ALLOW)
				bitmap_zero(vcpu->kvm->arch.pmu_filter, nr_events);
			else
				bitmap_fill(vcpu->kvm->arch.pmu_filter, nr_events);
		}

		if (filter.action == KVM_PMU_EVENT_ALLOW)
			bitmap_set(vcpu->kvm->arch.pmu_filter, filter.base_event, filter.nevents);
		else
			bitmap_clear(vcpu->kvm->arch.pmu_filter, filter.base_event, filter.nevents);

		mutex_unlock(&vcpu->kvm->lock);

		return 0;
	}
	case KVM_ARM_VCPU_PMU_V3_INIT:
		return kvm_arm_pmu_v3_init(vcpu);
	}

	return -ENXIO;
}