+static inline bool
+is_nxm_required(const struct cls_rule *rule, bool cookie_support,
+ ovs_be64 cookie)
+{
+ const struct flow_wildcards *wc = &rule->wc;
+ ovs_be32 cookie_hi;
+
+ /* Only NXM supports separately wildcards the Ethernet multicast bit. */
+ if (!(wc->wildcards & FWW_DL_DST) != !(wc->wildcards & FWW_ETH_MCAST)) {
+ return true;
+ }
+
+ /* Only NXM supports matching registers. */
+ if (!regs_fully_wildcarded(wc)) {
+ return true;
+ }
+
+ switch (wc->tun_id_mask) {
+ case CONSTANT_HTONLL(0):
+ /* Other formats can fully wildcard tun_id. */
+ break;
+
+ case CONSTANT_HTONLL(UINT64_MAX):
+ /* Only NXM supports matching tunnel ID, unless there is a cookie and
+ * the top 32 bits of the cookie are the desired tunnel ID value. */
+ cookie_hi = htonl(ntohll(cookie) >> 32);
+ if (!cookie_support
+ || (cookie_hi && cookie_hi != ntohll(rule->flow.tun_id))) {
+ return true;
+ }
+ break;
+
+ default:
+ /* Only NXM supports partial matches on tunnel ID. */
+ return true;
+ }
+
+ /* Other formats can express this rule. */
+ return false;
+}
+