diff --git a/usr.sbin/bhyve/mevent.c b/usr.sbin/bhyve/mevent.c
--- a/usr.sbin/bhyve/mevent.c
+++ b/usr.sbin/bhyve/mevent.c
@@ -64,8 +64,10 @@
 #define	MEVENT_MAX	64
 
 static pthread_t mevent_tid;
+static pthread_once_t mevent_once = PTHREAD_ONCE_INIT;
 static int mevent_timid = 43;
 static int mevent_pipefd[2];
+static int mfd;
 static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
 
 struct mevent {
@@ -124,6 +126,26 @@
 	}
 }
 
+static void
+mevent_init(void)
+{
+#ifndef WITHOUT_CAPSICUM
+	cap_rights_t rights;
+#endif
+
+	mfd = kqueue();
+	assert(mfd > 0);
+
+#ifndef WITHOUT_CAPSICUM
+	cap_rights_init(&rights, CAP_KQUEUE);
+	if (caph_rights_limit(mfd, &rights) == -1)
+		errx(EX_OSERR, "Unable to apply rights for sandbox");
+#endif
+
+	LIST_INIT(&change_head);
+	LIST_INIT(&global_head);
+}
+
 static int
 mevent_kq_filter(struct mevent *mevp)
 {
@@ -159,8 +181,24 @@
 	return (0);
 }
 
+static void
+mevent_populate(struct mevent *mevp, struct kevent *kev)
+{
+	if (mevp->me_type == EVF_TIMER) {
+		kev->ident = mevp->me_timid;
+		kev->data = mevp->me_msecs;
+	} else {
+		kev->ident = mevp->me_fd;
+		kev->data = 0;
+	}
+	kev->filter = mevent_kq_filter(mevp);
+	kev->flags = mevent_kq_flags(mevp);
+	kev->fflags = mevent_kq_fflags(mevp);
+	kev->udata = mevp;
+}
+
 static int
-mevent_build(int mfd, struct kevent *kev)
+mevent_build(struct kevent *kev)
 {
 	struct mevent *mevp, *tmpp;
 	int i;
@@ -177,17 +215,8 @@
 			 */
 			close(mevp->me_fd);
 		} else {
-			if (mevp->me_type == EVF_TIMER) {
-				kev[i].ident = mevp->me_timid;
-				kev[i].data = mevp->me_msecs;
-			} else {
-				kev[i].ident = mevp->me_fd;
-				kev[i].data = 0;
-			}
-			kev[i].filter = mevent_kq_filter(mevp);
-			kev[i].flags = mevent_kq_flags(mevp);
-			kev[i].fflags = mevent_kq_fflags(mevp);
-			kev[i].udata = mevp;
+			assert((mevp->me_state & EV_ADD) == 0);
+			mevent_populate(mevp, &kev[i]);
 			i++;
 		}
 
@@ -197,12 +226,6 @@
 		if (mevp->me_state & EV_DELETE) {
 			free(mevp);
 		} else {
-			/*
-			 * We need to add the event only once, so we can
-			 * reset the EV_ADD bit after it has been propagated
-			 * to the kevent() arguments the first time.
-			 */
-			mevp->me_state &= ~EV_ADD;
 			LIST_INSERT_HEAD(&global_head, mevp, me_list);
 		}
 
@@ -234,7 +257,9 @@
 	   void (*func)(int, enum ev_type, void *), void *param,
 	   int state)
 {
+	struct kevent kev;
 	struct mevent *lp, *mevp;
+	int ret;
 
 	if (tfd < 0 || func == NULL) {
 		return (NULL);
@@ -242,6 +267,8 @@
 
 	mevp = NULL;
 
+	pthread_once(&mevent_once, mevent_init);
+
 	mevent_qlock();
 
 	/*
@@ -262,7 +289,7 @@
 	}
 
 	/*
-	 * Allocate an entry, populate it, and add it to the change list.
+	 * Allocate an entry and populate it.
 	 */
 	mevp = calloc(1, sizeof(struct mevent));
 	if (mevp == NULL) {
@@ -277,11 +304,22 @@
 	mevp->me_type = type;
 	mevp->me_func = func;
 	mevp->me_param = param;
-
-	LIST_INSERT_HEAD(&change_head, mevp, me_list);
-	mevp->me_cq = 1;
 	mevp->me_state = state;
-	mevent_notify();
+
+	/*
+	 * Try to add the event.  If this fails, report the failure to
+	 * the caller.
+	 */
+	mevent_populate(mevp, &kev);
+	ret = kevent(mfd, &kev, 1, NULL, 0, NULL);
+	if (ret == -1) {
+		free(mevp);
+		mevp = NULL;
+		goto exit;
+	}
+
+	mevp->me_state &= ~EV_ADD;
+	LIST_INSERT_HEAD(&global_head, mevp, me_list);
 
 exit:
 	mevent_qunlock();
@@ -415,7 +453,6 @@
 	struct kevent changelist[MEVENT_MAX];
 	struct kevent eventlist[MEVENT_MAX];
 	struct mevent *pipev;
-	int mfd;
 	int numev;
 	int ret;
 #ifndef WITHOUT_CAPSICUM
@@ -425,14 +462,7 @@
 	mevent_tid = pthread_self();
 	mevent_set_name();
 
-	mfd = kqueue();
-	assert(mfd > 0);
-
-#ifndef WITHOUT_CAPSICUM
-	cap_rights_init(&rights, CAP_KQUEUE);
-	if (caph_rights_limit(mfd, &rights) == -1)
-		errx(EX_OSERR, "Unable to apply rights for sandbox");
-#endif
+	pthread_once(&mevent_once, mevent_init);
 
 	/*
 	 * Open the pipe that will be used for other threads to force
@@ -466,7 +496,7 @@
 		 * to eliminate the extra syscall. Currently better for
 		 * debug.
 		 */
-		numev = mevent_build(mfd, changelist);
+		numev = mevent_build(changelist);
 		if (numev) {
 			ret = kevent(mfd, changelist, numev, NULL, 0, NULL);
 			if (ret == -1) {