Index: head/sys/dev/sfxge/common/ef10_tx.c
===================================================================
--- head/sys/dev/sfxge/common/ef10_tx.c
+++ head/sys/dev/sfxge/common/ef10_tx.c
@@ -87,12 +87,16 @@
 	MCDI_IN_SET_DWORD(req, INIT_TXQ_IN_LABEL, label);
 	MCDI_IN_SET_DWORD(req, INIT_TXQ_IN_INSTANCE, instance);
 
-	MCDI_IN_POPULATE_DWORD_7(req, INIT_TXQ_IN_FLAGS,
+	MCDI_IN_POPULATE_DWORD_9(req, INIT_TXQ_IN_FLAGS,
 	    INIT_TXQ_IN_FLAG_BUFF_MODE, 0,
 	    INIT_TXQ_IN_FLAG_IP_CSUM_DIS,
 	    (flags & EFX_TXQ_CKSUM_IPV4) ? 0 : 1,
 	    INIT_TXQ_IN_FLAG_TCP_CSUM_DIS,
 	    (flags & EFX_TXQ_CKSUM_TCPUDP) ? 0 : 1,
+	    INIT_TXQ_EXT_IN_FLAG_INNER_IP_CSUM_EN,
+	    (flags & EFX_TXQ_CKSUM_INNER_IPV4) ? 1 : 0,
+	    INIT_TXQ_EXT_IN_FLAG_INNER_TCP_CSUM_EN,
+	    (flags & EFX_TXQ_CKSUM_INNER_TCPUDP) ? 1 : 0,
 	    INIT_TXQ_EXT_IN_FLAG_TSOV2_EN, (flags & EFX_TXQ_FATSOV2) ? 1 : 0,
 	    INIT_TXQ_IN_FLAG_TCP_UDP_ONLY, 0,
 	    INIT_TXQ_IN_CRC_MODE, 0,
@@ -197,14 +201,23 @@
 	__in		efx_txq_t *etp,
 	__out		unsigned int *addedp)
 {
+	efx_nic_cfg_t *encp = &enp->en_nic_cfg;
+	uint16_t inner_csum;
 	efx_qword_t desc;
 	efx_rc_t rc;
 
 	_NOTE(ARGUNUSED(id))
 
+	inner_csum = EFX_TXQ_CKSUM_INNER_IPV4 | EFX_TXQ_CKSUM_INNER_TCPUDP;
+	if (((flags & inner_csum) != 0) &&
+	    (encp->enc_tunnel_encapsulations_supported == 0)) {
+		rc = EINVAL;
+		goto fail1;
+	}
+
 	if ((rc = efx_mcdi_init_txq(enp, n, eep->ee_index, label, index, flags,
 	    esmp)) != 0)
-		goto fail1;
+		goto fail2;
 
 	/*
 	 * A previous user of this TX queue may have written a descriptor to the
@@ -215,19 +228,25 @@
 	 * a no-op TX option descriptor. See bug29981 for details.
 	 */
 	*addedp = 1;
-	EFX_POPULATE_QWORD_4(desc,
+	EFX_POPULATE_QWORD_6(desc,
 	    ESF_DZ_TX_DESC_IS_OPT, 1,
 	    ESF_DZ_TX_OPTION_TYPE, ESE_DZ_TX_OPTION_DESC_CRC_CSUM,
 	    ESF_DZ_TX_OPTION_UDP_TCP_CSUM,
 	    (flags & EFX_TXQ_CKSUM_TCPUDP) ? 1 : 0,
 	    ESF_DZ_TX_OPTION_IP_CSUM,
-	    (flags & EFX_TXQ_CKSUM_IPV4) ? 1 : 0);
+	    (flags & EFX_TXQ_CKSUM_IPV4) ? 1 : 0,
+	    ESF_DZ_TX_OPTION_INNER_UDP_TCP_CSUM,
+	    (flags & EFX_TXQ_CKSUM_INNER_TCPUDP) ? 1 : 0,
+	    ESF_DZ_TX_OPTION_INNER_IP_CSUM,
+	    (flags & EFX_TXQ_CKSUM_INNER_IPV4) ? 1 : 0);
 
 	EFSYS_MEM_WRITEQ(etp->et_esmp, 0, &desc);
 	ef10_tx_qpush(etp, *addedp, 0);
 
 	return (0);
 
+fail2:
+	EFSYS_PROBE(fail2);
 fail1:
 	EFSYS_PROBE1(fail1, efx_rc_t, rc);
 
Index: head/sys/dev/sfxge/common/efx.h
===================================================================
--- head/sys/dev/sfxge/common/efx.h
+++ head/sys/dev/sfxge/common/efx.h
@@ -2111,9 +2111,11 @@
 
 #define	EFX_TXQ_MAX_BUFS 8 /* Maximum independent of EFX_BUG35388_WORKAROUND. */
 
-#define	EFX_TXQ_CKSUM_IPV4	0x0001
-#define	EFX_TXQ_CKSUM_TCPUDP	0x0002
-#define	EFX_TXQ_FATSOV2		0x0004
+#define	EFX_TXQ_CKSUM_IPV4		0x0001
+#define	EFX_TXQ_CKSUM_TCPUDP		0x0002
+#define	EFX_TXQ_FATSOV2			0x0004
+#define	EFX_TXQ_CKSUM_INNER_IPV4	0x0008
+#define	EFX_TXQ_CKSUM_INNER_TCPUDP	0x0010
 
 extern	__checkReturn	efx_rc_t
 efx_tx_qcreate(
Index: head/sys/dev/sfxge/common/efx_tx.c
===================================================================
--- head/sys/dev/sfxge/common/efx_tx.c
+++ head/sys/dev/sfxge/common/efx_tx.c
@@ -905,6 +905,7 @@
 	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
 	efx_oword_t oword;
 	uint32_t size;
+	uint16_t inner_csum;
 	efx_rc_t rc;
 
 	_NOTE(ARGUNUSED(esmp))
@@ -934,6 +935,12 @@
 		goto fail3;
 	}
 
+	inner_csum = EFX_TXQ_CKSUM_INNER_IPV4 | EFX_TXQ_CKSUM_INNER_TCPUDP;
+	if ((flags & inner_csum) != 0) {
+		rc = EINVAL;
+		goto fail4;
+	}
+
 	/* Set up the new descriptor queue */
 	*addedp = 0;
 
@@ -956,6 +963,8 @@
 
 	return (0);
 
+fail4:
+	EFSYS_PROBE(fail4);
 fail3:
 	EFSYS_PROBE(fail3);
 fail2: