Index: sys/net80211/ieee80211.c
===================================================================
--- sys/net80211/ieee80211.c
+++ sys/net80211/ieee80211.c
@@ -233,6 +233,8 @@
 	DEFAULTRATES(IEEE80211_MODE_VHT_2GHZ,	 ieee80211_rateset_11g);
 	DEFAULTRATES(IEEE80211_MODE_VHT_5GHZ,	 ieee80211_rateset_11a);
 
+	ieee80211_init_suphtrates(ic);
+
 	/*
 	 * Setup required information to fill the mcsset field, if driver did
 	 * not. Assume a 2T2R setup for historic reasons.
@@ -1905,6 +1907,14 @@
 	return &ic->ic_sup_rates[ieee80211_chan2mode(c)];
 }
 
+/* XXX inline or eliminate? */
+const struct ieee80211_htrateset *
+ieee80211_get_suphtrates(struct ieee80211com *ic,
+    const struct ieee80211_channel *c)
+{
+	return &ic->ic_sup_htrates;
+}
+
 void
 ieee80211_announce(struct ieee80211com *ic)
 {
Index: sys/net80211/ieee80211_ht.h
===================================================================
--- sys/net80211/ieee80211_ht.h
+++ sys/net80211/ieee80211_ht.h
@@ -177,8 +177,7 @@
 	uint16_t	ht40_rate_400ns;
 };
 extern const struct ieee80211_mcs_rates ieee80211_htrates[];
-const struct ieee80211_htrateset *ieee80211_get_suphtrates(
-		struct ieee80211com *, const struct ieee80211_channel *);
+void	ieee80211_init_suphtrates(struct ieee80211com *);
 
 struct ieee80211_node;
 int	ieee80211_setup_htrates(struct ieee80211_node *,
Index: sys/net80211/ieee80211_ht.c
===================================================================
--- sys/net80211/ieee80211_ht.c
+++ sys/net80211/ieee80211_ht.c
@@ -421,19 +421,17 @@
 		ht_announce(ic, IEEE80211_MODE_11NG);
 }
 
-static struct ieee80211_htrateset htrateset;
-
-const struct ieee80211_htrateset *
-ieee80211_get_suphtrates(struct ieee80211com *ic,
-    const struct ieee80211_channel *c)
+void
+ieee80211_init_suphtrates(struct ieee80211com *ic)
 {
 #define	ADDRATE(x)	do {						\
-	htrateset.rs_rates[htrateset.rs_nrates] = x;			\
-	htrateset.rs_nrates++;						\
+	htrateset->rs_rates[htrateset->rs_nrates] = x;			\
+	htrateset->rs_nrates++;						\
 } while (0)
+	struct ieee80211_htrateset *htrateset = &ic->ic_sup_htrates;
 	int i;
 
-	memset(&htrateset, 0, sizeof(struct ieee80211_htrateset));
+	memset(htrateset, 0, sizeof(struct ieee80211_htrateset));
 	for (i = 0; i < ic->ic_txstream * 8; i++)
 		ADDRATE(i);
 	if ((ic->ic_htcaps & IEEE80211_HTCAP_CHWIDTH40) &&
@@ -453,7 +451,6 @@
 				ADDRATE(i);
 		}
 	}
-	return &htrateset;
 #undef	ADDRATE
 }
 
Index: sys/net80211/ieee80211_ioctl.c
===================================================================
--- sys/net80211/ieee80211_ioctl.c
+++ sys/net80211/ieee80211_ioctl.c
@@ -2226,13 +2226,19 @@
 }
 
 static int
-checkmcs(int mcs)
+checkmcs(const struct ieee80211_htrateset *rs, int mcs)
 {
+	int rate_val = IEEE80211_RV(mcs);
+	int i;
+
 	if (mcs == IEEE80211_FIXED_RATE_NONE)
 		return 1;
 	if ((mcs & IEEE80211_RATE_MCS) == 0)	/* MCS always have 0x80 set */
 		return 0;
-	return (mcs & 0x7f) <= 31;	/* XXX could search ht rate set */
+	for (i = 0; i < rs->rs_nrates; i++)
+		if (IEEE80211_RV(rs->rs_rates[i]) == rate_val)
+			return 1;
+	return 0;
 }
 
 static int
@@ -2242,6 +2248,7 @@
 	struct ieee80211com *ic = vap->iv_ic;
 	struct ieee80211_txparams_req parms;	/* XXX stack use? */
 	struct ieee80211_txparam *src, *dst;
+	const struct ieee80211_htrateset *rs_ht;
 	const struct ieee80211_rateset *rs;
 	int error, mode, changed, is11n, nmodes;
 
@@ -2260,23 +2267,24 @@
 		src = &parms.params[mode];
 		dst = &vap->iv_txparms[mode];
 		rs = &ic->ic_sup_rates[mode];	/* NB: 11n maps to legacy */
+		rs_ht = &ic->ic_sup_htrates;
 		is11n = (mode == IEEE80211_MODE_11NA ||
 			 mode == IEEE80211_MODE_11NG);
 		if (src->ucastrate != dst->ucastrate) {
 			if (!checkrate(rs, src->ucastrate) &&
-			    (!is11n || !checkmcs(src->ucastrate)))
+			    (!is11n || !checkmcs(rs_ht, src->ucastrate)))
 				return EINVAL;
 			changed++;
 		}
 		if (src->mcastrate != dst->mcastrate) {
 			if (!checkrate(rs, src->mcastrate) &&
-			    (!is11n || !checkmcs(src->mcastrate)))
+			    (!is11n || !checkmcs(rs_ht, src->mcastrate)))
 				return EINVAL;
 			changed++;
 		}
 		if (src->mgmtrate != dst->mgmtrate) {
 			if (!checkrate(rs, src->mgmtrate) &&
-			    (!is11n || !checkmcs(src->mgmtrate)))
+			    (!is11n || !checkmcs(rs_ht, src->mgmtrate)))
 				return EINVAL;
 			changed++;
 		}
Index: sys/net80211/ieee80211_var.h
===================================================================
--- sys/net80211/ieee80211_var.h
+++ sys/net80211/ieee80211_var.h
@@ -175,6 +175,7 @@
 	uint16_t		ic_holdover;	/* PM hold over duration */
 	uint16_t		ic_txpowlimit;	/* global tx power limit */
 	struct ieee80211_rateset ic_sup_rates[IEEE80211_MODE_MAX];
+	struct ieee80211_htrateset ic_sup_htrates;
 
 	/*
 	 * Channel state:
@@ -692,6 +693,8 @@
 void	ieee80211_vap_detach(struct ieee80211vap *);
 const struct ieee80211_rateset *ieee80211_get_suprates(struct ieee80211com *ic,
 		const struct ieee80211_channel *);
+const struct ieee80211_htrateset *ieee80211_get_suphtrates(
+		struct ieee80211com *, const struct ieee80211_channel *);
 void	ieee80211_announce(struct ieee80211com *);
 void	ieee80211_announce_channels(struct ieee80211com *);
 void	ieee80211_drain(struct ieee80211com *);