//  [c]
long kvm_arch_vcpu_ioctl(struct file *filp,
			 unsigned int ioctl, unsigned long arg)
{
	struct kvm_vcpu *vcpu = filp->private_data;
	void __user *argp = (void __user *)arg;
	int r;
	union {
		struct kvm_lapic_state *lapic;
		struct kvm_xsave *xsave;
		struct kvm_xcrs *xcrs;
		void *buffer;
	} u;

	u.buffer = NULL;
	switch (ioctl) {
	case KVM_GET_LAPIC: {
		r = -EINVAL;
		if (!vcpu->arch.apic)
			goto out;
		u.lapic = kzalloc(sizeof(struct kvm_lapic_state), GFP_KERNEL);

		r = -ENOMEM;
		if (!u.lapic)
			goto out;
		r = kvm_vcpu_ioctl_get_lapic(vcpu, u.lapic);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(argp, u.lapic, sizeof(struct kvm_lapic_state)))
			goto out;
		r = 0;
		break;
	}
	case KVM_SET_LAPIC: {
		r = -EINVAL;
		if (!vcpu->arch.apic)
			goto out;
		u.lapic = memdup_user(argp, sizeof(*u.lapic));
		if (IS_ERR(u.lapic))
			return PTR_ERR(u.lapic);

		r = kvm_vcpu_ioctl_set_lapic(vcpu, u.lapic);
		break;
	}
	case KVM_INTERRUPT: {
		struct kvm_interrupt irq;

		r = -EFAULT;
		if (copy_from_user(&irq, argp, sizeof irq))
			goto out;
		r = kvm_vcpu_ioctl_interrupt(vcpu, &irq);
		break;
	}
	case KVM_NMI: {
		r = kvm_vcpu_ioctl_nmi(vcpu);
		break;
	}
	case KVM_SET_CPUID: {
		struct kvm_cpuid __user *cpuid_arg = argp;
		struct kvm_cpuid cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_set_cpuid(vcpu, &cpuid, cpuid_arg->entries);
		break;
	}
	case KVM_SET_CPUID2: {
		struct kvm_cpuid2 __user *cpuid_arg = argp;
		struct kvm_cpuid2 cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_set_cpuid2(vcpu, &cpuid,
					      cpuid_arg->entries);
		break;
	}
	case KVM_GET_CPUID2: {
		struct kvm_cpuid2 __user *cpuid_arg = argp;
		struct kvm_cpuid2 cpuid;

		r = -EFAULT;
		if (copy_from_user(&cpuid, cpuid_arg, sizeof cpuid))
			goto out;
		r = kvm_vcpu_ioctl_get_cpuid2(vcpu, &cpuid,
					      cpuid_arg->entries);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(cpuid_arg, &cpuid, sizeof cpuid))
			goto out;
		r = 0;
		break;
	}
	case KVM_GET_MSRS:
		r = msr_io(vcpu, argp, kvm_get_msr, 1);
		break;
	case KVM_SET_MSRS:
		r = msr_io(vcpu, argp, do_set_msr, 0);
		break;
	case KVM_TPR_ACCESS_REPORTING: {
		struct kvm_tpr_access_ctl tac;

		r = -EFAULT;
		if (copy_from_user(&tac, argp, sizeof tac))
			goto out;
		r = vcpu_ioctl_tpr_access_reporting(vcpu, &tac);
		if (r)
			goto out;
		r = -EFAULT;
		if (copy_to_user(argp, &tac, sizeof tac))
			goto out;
		r = 0;
		break;
	};
	case KVM_SET_VAPIC_ADDR: {
		struct kvm_vapic_addr va;

		r = -EINVAL;
		if (!irqchip_in_kernel(vcpu->kvm))
			goto out;
		r = -EFAULT;
		if (copy_from_user(&va, argp, sizeof va))
			goto out;
		r = kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
		break;
	}
	case KVM_X86_SETUP_MCE: {
		u64 mcg_cap;

		r = -EFAULT;
		if (copy_from_user(&mcg_cap, argp, sizeof mcg_cap))
			goto out;
		r = kvm_vcpu_ioctl_x86_setup_mce(vcpu, mcg_cap);
		break;
	}
	case KVM_X86_SET_MCE: {
		struct kvm_x86_mce mce;

		r = -EFAULT;
		if (copy_from_user(&mce, argp, sizeof mce))
			goto out;
		r = kvm_vcpu_ioctl_x86_set_mce(vcpu, &mce);
		break;
	}
	case KVM_GET_VCPU_EVENTS: {
		struct kvm_vcpu_events events;

		kvm_vcpu_ioctl_x86_get_vcpu_events(vcpu, &events);

		r = -EFAULT;
		if (copy_to_user(argp, &events, sizeof(struct kvm_vcpu_events)))
			break;
		r = 0;
		break;
	}
	case KVM_SET_VCPU_EVENTS: {
		struct kvm_vcpu_events events;

		r = -EFAULT;
		if (copy_from_user(&events, argp, sizeof(struct kvm_vcpu_events)))
			break;

		r = kvm_vcpu_ioctl_x86_set_vcpu_events(vcpu, &events);
		break;
	}
	case KVM_GET_DEBUGREGS: {
		struct kvm_debugregs dbgregs;

		kvm_vcpu_ioctl_x86_get_debugregs(vcpu, &dbgregs);

		r = -EFAULT;
		if (copy_to_user(argp, &dbgregs,
				 sizeof(struct kvm_debugregs)))
			break;
		r = 0;
		break;
	}
	case KVM_SET_DEBUGREGS: {
		struct kvm_debugregs dbgregs;

		r = -EFAULT;
		if (copy_from_user(&dbgregs, argp,
				   sizeof(struct kvm_debugregs)))
			break;

		r = kvm_vcpu_ioctl_x86_set_debugregs(vcpu, &dbgregs);
		break;
	}
	case KVM_GET_XSAVE: {
		u.xsave = kzalloc(sizeof(struct kvm_xsave), GFP_KERNEL);
		r = -ENOMEM;
		if (!u.xsave)
			break;

		kvm_vcpu_ioctl_x86_get_xsave(vcpu, u.xsave);

		r = -EFAULT;
		if (copy_to_user(argp, u.xsave, sizeof(struct kvm_xsave)))
			break;
		r = 0;
		break;
	}
	case KVM_SET_XSAVE: {
		u.xsave = memdup_user(argp, sizeof(*u.xsave));
		if (IS_ERR(u.xsave))
			return PTR_ERR(u.xsave);

		r = kvm_vcpu_ioctl_x86_set_xsave(vcpu, u.xsave);
		break;
	}
	case KVM_GET_XCRS: {
		u.xcrs = kzalloc(sizeof(struct kvm_xcrs), GFP_KERNEL);
		r = -ENOMEM;
		if (!u.xcrs)
			break;

		kvm_vcpu_ioctl_x86_get_xcrs(vcpu, u.xcrs);

		r = -EFAULT;
		if (copy_to_user(argp, u.xcrs,
				 sizeof(struct kvm_xcrs)))
			break;
		r = 0;
		break;
	}
	case KVM_SET_XCRS: {
		u.xcrs = memdup_user(argp, sizeof(*u.xcrs));
		if (IS_ERR(u.xcrs))
			return PTR_ERR(u.xcrs);

		r = kvm_vcpu_ioctl_x86_set_xcrs(vcpu, u.xcrs);
		break;
	}
	case KVM_SET_TSC_KHZ: {
		u32 user_tsc_khz;

		r = -EINVAL;
		user_tsc_khz = (u32)arg;

		if (user_tsc_khz >= kvm_max_guest_tsc_khz)
			goto out;

		if (user_tsc_khz == 0)
			user_tsc_khz = tsc_khz;

		kvm_set_tsc_khz(vcpu, user_tsc_khz);

		r = 0;
		goto out;
	}
	case KVM_GET_TSC_KHZ: {
		r = vcpu->arch.virtual_tsc_khz;
		goto out;
	}
	case KVM_KVMCLOCK_CTRL: {
		r = kvm_set_guest_paused(vcpu);
		goto out;
	}
	default:
		r = -EINVAL;
	}
out:
	kfree(u.buffer);
	return r;
}