static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
				   struct kvm_enable_cap *cap)
{
	int r;

	if (cap->flags)
		return -EINVAL;

	switch (cap->cap) {
	case KVM_CAP_DISABLE_QUIRKS:
		kvm->arch.disabled_quirks = cap->args[0];
		r = 0;
		break;
	case KVM_CAP_SPLIT_IRQCHIP: {
		mutex_lock(&kvm->lock);
		r = -EINVAL;
		if (cap->args[0] > MAX_NR_RESERVED_IOAPIC_PINS)
			goto split_irqchip_unlock;
		r = -EEXIST;
		if (irqchip_in_kernel(kvm))
			goto split_irqchip_unlock;
		if (kvm->created_vcpus)
			goto split_irqchip_unlock;
		r = kvm_setup_empty_irq_routing(kvm);
		if (r)
			goto split_irqchip_unlock;
		/* Pairs with irqchip_in_kernel. */
		smp_wmb();
		kvm->arch.irqchip_mode = KVM_IRQCHIP_SPLIT;
		kvm->arch.nr_reserved_ioapic_pins = cap->args[0];
		r = 0;
split_irqchip_unlock:
		mutex_unlock(&kvm->lock);
		break;
	}
	case KVM_CAP_X2APIC_API:
		r = -EINVAL;
		if (cap->args[0] & ~KVM_X2APIC_API_VALID_FLAGS)
			break;

		if (cap->args[0] & KVM_X2APIC_API_USE_32BIT_IDS)
			kvm->arch.x2apic_format = true;
		if (cap->args[0] & KVM_X2APIC_API_DISABLE_BROADCAST_QUIRK)
			kvm->arch.x2apic_broadcast_quirk_disabled = true;

		r = 0;
		break;
	case KVM_CAP_X86_DISABLE_EXITS:
		r = -EINVAL;
		if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS)
			break;

		if ((cap->args[0] & KVM_X86_DISABLE_EXITS_MWAIT) &&
			kvm_can_mwait_in_guest())
			kvm->arch.mwait_in_guest = true;
		if (cap->args[0] & KVM_X86_DISABLE_EXITS_HLT)
			kvm->arch.hlt_in_guest = true;
		if (cap->args[0] & KVM_X86_DISABLE_EXITS_PAUSE)
			kvm->arch.pause_in_guest = true;
		r = 0;
		break;
	case KVM_CAP_MSR_PLATFORM_INFO:
		kvm->arch.guest_can_read_msr_platform_info = cap->args[0];
		r = 0;
		break;
	case KVM_CAP_EXCEPTION_PAYLOAD:
		kvm->arch.exception_payload_enabled = cap->args[0];
		r = 0;
		break;
	default:
		r = -EINVAL;
		break;
	}
	return r;
}
Unknown