diff --git a/sys/altq/if_altq.h b/sys/altq/if_altq.h
index c441651..e48f0a6 100644
--- a/sys/altq/if_altq.h
+++ b/sys/altq/if_altq.h
@@ -45,6 +45,7 @@ struct	ifaltq {
 	int	ifq_len;
 	int	ifq_maxlen;
 	int	ifq_drops;
+	kmutex_t	*ifq_lock;
 
 	/* alternate queueing related fields */
 	int	altq_type;		/* discipline type */
diff --git a/sys/dev/pci/if_wm.c b/sys/dev/pci/if_wm.c
index 1c41f32..3b947ac 100644
--- a/sys/dev/pci/if_wm.c
+++ b/sys/dev/pci/if_wm.c
@@ -141,6 +141,10 @@ int	wm_debug = WM_DEBUG_TX | WM_DEBUG_RX | WM_DEBUG_LINK | WM_DEBUG_GMII
 #define	DPRINTF(x, y)	/* nothing */
 #endif /* WM_DEBUG */
 
+#ifdef NET_MPSAFE
+#define WM_MPSAFE	1
+#endif
+
 /*
  * Transmit descriptor list size.  Due to errata, we can only have
  * 256 hardware descriptors in the ring on < 82544, but we use 4096
@@ -380,8 +384,14 @@ struct wm_softc {
 	int sc_mchash_type;		/* multicast filter offset */
 
 	krndsource_t rnd_source;	/* random source */
+
+	kmutex_t *sc_txrx_lock;		/* lock for tx/rx operations */
+					/* XXX need separation? */
 };
 
+#define WM_LOCK(_sc)	if ((_sc)->sc_txrx_lock) mutex_enter((_sc)->sc_txrx_lock)
+#define WM_UNLOCK(_sc)	if ((_sc)->sc_txrx_lock) mutex_exit((_sc)->sc_txrx_lock)
+
 #define	WM_RXCHAIN_RESET(sc)						\
 do {									\
 	(sc)->sc_rxtailp = &(sc)->sc_rxhead;				\
@@ -495,7 +505,9 @@ do {									\
 } while (/*CONSTCOND*/0)
 
 static void	wm_start(struct ifnet *);
+static void	wm_start_locked(struct ifnet *);
 static void	wm_nq_start(struct ifnet *);
+static void	wm_nq_start_locked(struct ifnet *);
 static void	wm_watchdog(struct ifnet *);
 static int	wm_ifflags_cb(struct ethercom *);
 static int	wm_ioctl(struct ifnet *, u_long, void *);
@@ -1315,6 +1327,9 @@ wm_attach(device_t parent, device_t self, void *aux)
 		return;
 	}
 	intrstr = pci_intr_string(pc, ih, intrbuf, sizeof(intrbuf));
+#ifdef WM_MPSAFE
+	pci_intr_setattr(pc, &ih, PCI_INTR_MPSAFE, true);
+#endif
 	sc->sc_ih = pci_intr_establish(pc, ih, IPL_NET, wm_intr, sc);
 	if (sc->sc_ih == NULL) {
 		aprint_error_dev(sc->sc_dev, "unable to establish interrupt");
@@ -2051,6 +2066,12 @@ wm_attach(device_t parent, device_t self, void *aux)
 		ifp->if_capabilities |= IFCAP_TSOv6;
 	}
 
+#ifdef WM_MPSAFE
+	sc->sc_txrx_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET);
+#else
+	sc->sc_txrx_lock = NULL;
+#endif
+
 	/*
 	 * Attach the interface.
 	 */
@@ -2218,6 +2239,9 @@ wm_detach(device_t self, int flags __unused)
 		sc->sc_ios = 0;
 	}
 
+	if (sc->sc_txrx_lock)
+		mutex_obj_free(sc->sc_txrx_lock);
+
 	return 0;
 }
 
@@ -2546,6 +2570,16 @@ static void
 wm_start(struct ifnet *ifp)
 {
 	struct wm_softc *sc = ifp->if_softc;
+
+	WM_LOCK(sc);
+	wm_start_locked(ifp);
+	WM_UNLOCK(sc);
+}
+
+static void
+wm_start_locked(struct ifnet *ifp)
+{
+	struct wm_softc *sc = ifp->if_softc;
 	struct mbuf *m0;
 	struct m_tag *mtag;
 	struct wm_txsoft *txs;
@@ -3053,6 +3087,16 @@ static void
 wm_nq_start(struct ifnet *ifp)
 {
 	struct wm_softc *sc = ifp->if_softc;
+
+	WM_LOCK(sc);
+	wm_nq_start_locked(ifp);
+	WM_UNLOCK(sc);
+}
+
+static void
+wm_nq_start_locked(struct ifnet *ifp)
+{
+	struct wm_softc *sc = ifp->if_softc;
 	struct mbuf *m0;
 	struct m_tag *mtag;
 	struct wm_txsoft *txs;
@@ -3335,7 +3379,9 @@ wm_watchdog(struct ifnet *ifp)
 	 * Since we're using delayed interrupts, sweep up
 	 * before we report an error.
 	 */
+	WM_LOCK(sc);
 	wm_txintr(sc);
+	WM_UNLOCK(sc);
 
 	if (sc->sc_txfree != WM_NTXDESC(sc)) {
 #ifdef WM_DEBUG
@@ -3486,6 +3532,8 @@ wm_intr(void *arg)
 
 		handled = 1;
 
+		WM_LOCK(sc);
+
 #if defined(WM_DEBUG) || defined(WM_EVENT_COUNTERS)
 		if (icr & (ICR_RXDMT0|ICR_RXT0)) {
 			DPRINTF(WM_DEBUG_RX,
@@ -3512,6 +3560,8 @@ wm_intr(void *arg)
 			wm_linkintr(sc, icr);
 		}
 
+		WM_UNLOCK(sc);
+
 		if (icr & ICR_RXO) {
 #if defined(WM_DEBUG)
 			log(LOG_WARNING, "%s: Receive overrun\n",
@@ -3818,7 +3868,9 @@ wm_rxintr(struct wm_softc *sc)
 		bpf_mtap(ifp, m);
 
 		/* Pass it on. */
+		WM_UNLOCK(sc);
 		(*ifp->if_input)(ifp, m);
+		WM_LOCK(sc);
 	}
 
 	/* Update the receive pointer. */
diff --git a/sys/net/if.c b/sys/net/if.c
index 2a6fa0f..f8429b1 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -611,6 +611,12 @@ if_attach(ifnet_t *ifp)
 	ifp->if_snd.altq_ifp  = ifp;
 #endif
 
+#ifdef NET_MPSAFE
+	ifp->if_snd.ifq_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NET);
+#else
+	ifp->if_snd.ifq_lock = NULL;
+#endif
+
 	ifp->if_pfil = pfil_head_create(PFIL_TYPE_IFNET, ifp);
 	(void)pfil_run_hooks(if_pfil,
 	    (struct mbuf **)PFIL_IFNET_ATTACH, ifp, PFIL_IFNET);
@@ -732,6 +738,9 @@ if_detach(struct ifnet *ifp)
 		altq_detach(&ifp->if_snd);
 #endif
 
+	if (ifp->if_snd.ifq_lock)
+		mutex_obj_free(ifp->if_snd.ifq_lock);
+
 	sysctl_teardown(&ifp->if_sysctl_log);
 
 #if NCARP > 0
diff --git a/sys/net/if.h b/sys/net/if.h
index bc2c240..ca5d11e 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -86,6 +86,8 @@
 #include <net/pktqueue.h>
 #endif
 
+//#define NET_MPSAFE 1
+
 /*
  * Always include ALTQ glue here -- we use the ALTQ interface queue
  * structure even when ALTQ is not configured into the kernel so that
@@ -198,11 +200,12 @@ struct if_data {
  * Structure defining a queue for a network interface.
  */
 struct ifqueue {
-	struct	mbuf *ifq_head;
-	struct	mbuf *ifq_tail;
-	int	ifq_len;
-	int	ifq_maxlen;
-	int	ifq_drops;
+	struct		mbuf *ifq_head;
+	struct		mbuf *ifq_tail;
+	int		ifq_len;
+	int		ifq_maxlen;
+	int		ifq_drops;
+	kmutex_t	*ifq_lock;
 };
 
 struct ifnet_lock;
@@ -230,6 +233,7 @@ struct ifnet_lock {
 				 * before they leave.
 				 */
 };
+
 #endif /* _KERNEL */
 
 /*
@@ -424,6 +428,9 @@ typedef struct ifnet {
 	"\23TSO6"		\
 	"\24LRO"		\
 
+#define IFQ_LOCK(_ifq)		if ((_ifq)->ifq_lock) mutex_enter((_ifq)->ifq_lock)
+#define IFQ_UNLOCK(_ifq)	if ((_ifq)->ifq_lock) mutex_exit((_ifq)->ifq_lock)
+
 /*
  * Output queues (ifp->if_snd) and internetwork datagram level (pup level 1)
  * input routines have queues of messages stored on ifqueue structures
@@ -752,6 +759,7 @@ do {									\
 
 #define IFQ_ENQUEUE(ifq, m, pattr, err)					\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (ALTQ_IS_ENABLED((ifq)))					\
 		ALTQ_ENQUEUE((ifq), (m), (pattr), (err));		\
 	else {								\
@@ -765,34 +773,41 @@ do {									\
 	}								\
 	if ((err))							\
 		(ifq)->ifq_drops++;					\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 
 #define IFQ_DEQUEUE(ifq, m)						\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (TBR_IS_ENABLED((ifq)))					\
 		(m) = tbr_dequeue((ifq), ALTDQ_REMOVE);			\
 	else if (ALTQ_IS_ENABLED((ifq)))				\
 		ALTQ_DEQUEUE((ifq), (m));				\
 	else								\
 		IF_DEQUEUE((ifq), (m));					\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 
 #define	IFQ_POLL(ifq, m)						\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (TBR_IS_ENABLED((ifq)))					\
 		(m) = tbr_dequeue((ifq), ALTDQ_POLL);			\
 	else if (ALTQ_IS_ENABLED((ifq)))				\
 		ALTQ_POLL((ifq), (m));					\
 	else								\
 		IF_POLL((ifq), (m));					\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 
 #define	IFQ_PURGE(ifq)							\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (ALTQ_IS_ENABLED((ifq)))					\
 		ALTQ_PURGE((ifq));					\
 	else								\
 		IF_PURGE((ifq));					\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 
 #define	IFQ_SET_READY(ifq)						\
@@ -802,6 +817,7 @@ do {									\
 
 #define	IFQ_CLASSIFY(ifq, m, af, pattr)					\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (ALTQ_IS_ENABLED((ifq))) {					\
 		if (ALTQ_NEEDS_CLASSIFY((ifq)))				\
 			(pattr)->pattr_class = (*(ifq)->altq_classify)	\
@@ -809,6 +825,7 @@ do {									\
 		(pattr)->pattr_af = (af);				\
 		(pattr)->pattr_hdr = mtod((m), void *);		\
 	}								\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 #else /* ! ALTQ */
 #define	ALTQ_DECL(x)		/* nothing */
@@ -816,6 +833,7 @@ do {									\
 
 #define	IFQ_ENQUEUE(ifq, m, pattr, err)					\
 do {									\
+	IFQ_LOCK((ifq));						\
 	if (IF_QFULL((ifq))) {						\
 		m_freem((m));						\
 		(err) = ENOBUFS;					\
@@ -825,13 +843,29 @@ do {									\
 	}								\
 	if ((err))							\
 		(ifq)->ifq_drops++;					\
+	IFQ_UNLOCK((ifq));						\
 } while (/*CONSTCOND*/ 0)
 
-#define	IFQ_DEQUEUE(ifq, m)	IF_DEQUEUE((ifq), (m))
+#define	IFQ_DEQUEUE(ifq, m)						\
+do {									\
+	IFQ_LOCK((ifq));						\
+	IF_DEQUEUE((ifq), (m));						\
+	IFQ_UNLOCK((ifq));						\
+} while (/*CONSTCOND*/ 0)
 
-#define	IFQ_POLL(ifq, m)	IF_POLL((ifq), (m))
+#define	IFQ_POLL(ifq, m)						\
+do {									\
+	IFQ_LOCK((ifq));						\
+	IF_POLL((ifq), (m));						\
+	IFQ_UNLOCK((ifq));						\
+} while (/*CONSTCOND*/ 0)
 
-#define	IFQ_PURGE(ifq)		IF_PURGE((ifq))
+#define	IFQ_PURGE(ifq)							\
+do {									\
+	IFQ_LOCK((ifq));						\
+	IF_PURGE((ifq));						\
+	IFQ_UNLOCK((ifq));						\
+} while (/*CONSTCOND*/ 0)
 
 #define	IFQ_SET_READY(ifq)	/* nothing */