int
v4v_init(struct domain *d)
{
    struct v4v_domain *v4v;
    evtchn_port_t port;
    int i;
    int rc;

    v4v = xmalloc(struct v4v_domain);
    if ( !v4v )
        return -ENOMEM;

    rc = evtchn_alloc_unbound_domain(d, &port, d->domain_id);
    if ( rc )
        return rc;

    rwlock_init(&v4v->lock);

    v4v->evtchn_port = port;
    for ( i = 0; i < V4V_HTABLE_SIZE; ++i )
        INIT_HLIST_HEAD(&v4v->ring_hash[i]);

    write_lock(&v4v_lock);
    d->v4v = v4v;
    write_unlock(&v4v_lock);

    return 0;
}