static int kvm_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct kvm_vcpu *vcpu = file->private_data;
	unsigned long pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

	if ((kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff) ||
	     kvm_page_in_dirty_ring(vcpu->kvm, vma->vm_pgoff + pages - 1)) &&
	    ((vma->vm_flags & VM_EXEC) || !(vma->vm_flags & VM_SHARED)))
		return -EINVAL;

	vma->vm_ops = &kvm_vcpu_vm_ops;
	return 0;
}