New upstream version 17.11.5upstream-17.11-stable

Change-Id: I8d2aa1aee2a9a78614dff5a01008f91e88e810c7
Signed-off-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>

29 files changed, 319 insertions, 355 deletions

diff --git a/drivers/net/sfc/base/ef10_ev.c b/drivers/net/sfc/base/ef10_ev.c
index d9389dab..b2a4a28e 100644
--- a/drivers/net/sfc/base/ef10_ev.c
+++ b/drivers/net/sfc/base/ef10_ev.c
@@ -97,11 +97,10 @@ efx_mcdi_set_evq_tmr(
 	__in		uint32_t timer_ns)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SET_EVQ_TMR_IN_LEN,
-			    MC_CMD_SET_EVQ_TMR_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SET_EVQ_TMR_IN_LEN,
+		MC_CMD_SET_EVQ_TMR_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_EVQ_TMR;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_EVQ_TMR_IN_LEN;
@@ -147,9 +146,9 @@ efx_mcdi_init_evq(
 	__in		boolean_t low_latency)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[
-	    MAX(MC_CMD_INIT_EVQ_IN_LEN(EFX_EVQ_NBUFS(EFX_EVQ_MAXNEVS)),
-		MC_CMD_INIT_EVQ_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload,
+		MC_CMD_INIT_EVQ_IN_LEN(EFX_EVQ_NBUFS(EFX_EVQ_MAXNEVS)),
+		MC_CMD_INIT_EVQ_OUT_LEN);
 	efx_qword_t *dma_addr;
 	uint64_t addr;
 	int npages;
@@ -164,7 +163,6 @@ efx_mcdi_init_evq(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_INIT_EVQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_INIT_EVQ_IN_LEN(npages);
@@ -284,9 +282,9 @@ efx_mcdi_init_evq_v2(
 	__in		uint32_t flags)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[
-		MAX(MC_CMD_INIT_EVQ_V2_IN_LEN(EFX_EVQ_NBUFS(EFX_EVQ_MAXNEVS)),
-		    MC_CMD_INIT_EVQ_V2_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload,
+		MC_CMD_INIT_EVQ_V2_IN_LEN(EFX_EVQ_NBUFS(EFX_EVQ_MAXNEVS)),
+		MC_CMD_INIT_EVQ_V2_OUT_LEN);
 	boolean_t interrupting;
 	unsigned int evq_type;
 	efx_qword_t *dma_addr;
@@ -301,7 +299,6 @@ efx_mcdi_init_evq_v2(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_INIT_EVQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_INIT_EVQ_V2_IN_LEN(npages);
@@ -408,11 +405,10 @@ efx_mcdi_fini_evq(
 	__in		uint32_t instance)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FINI_EVQ_IN_LEN,
-			    MC_CMD_FINI_EVQ_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FINI_EVQ_IN_LEN,
+		MC_CMD_FINI_EVQ_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FINI_EVQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FINI_EVQ_IN_LEN;
@@ -624,8 +620,8 @@ efx_mcdi_driver_event(
 	__in		efx_qword_t data)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_DRIVER_EVENT_IN_LEN,
-			    MC_CMD_DRIVER_EVENT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_DRIVER_EVENT_IN_LEN,
+		MC_CMD_DRIVER_EVENT_OUT_LEN);
 	efx_rc_t rc;
 
 	req.emr_cmd = MC_CMD_DRIVER_EVENT;
diff --git a/drivers/net/sfc/base/ef10_filter.c b/drivers/net/sfc/base/ef10_filter.c
index e1faf1dd..ca15c53e 100644
--- a/drivers/net/sfc/base/ef10_filter.c
+++ b/drivers/net/sfc/base/ef10_filter.c
@@ -190,11 +190,10 @@ efx_mcdi_filter_op_add(
 	__inout		ef10_filter_handle_t *handle)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FILTER_OP_EXT_IN_LEN,
-			    MC_CMD_FILTER_OP_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FILTER_OP_EXT_IN_LEN,
+		MC_CMD_FILTER_OP_EXT_OUT_LEN);
 	efx_rc_t rc;
 
-	memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FILTER_OP;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FILTER_OP_EXT_IN_LEN;
@@ -353,11 +352,10 @@ efx_mcdi_filter_op_delete(
 	__inout		ef10_filter_handle_t *handle)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FILTER_OP_EXT_IN_LEN,
-			    MC_CMD_FILTER_OP_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FILTER_OP_EXT_IN_LEN,
+		MC_CMD_FILTER_OP_EXT_OUT_LEN);
 	efx_rc_t rc;
 
-	memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FILTER_OP;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FILTER_OP_EXT_IN_LEN;
@@ -917,13 +915,12 @@ efx_mcdi_get_parser_disp_info(
 	__out				size_t *list_lengthp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PARSER_DISP_INFO_IN_LEN,
-			    MC_CMD_GET_PARSER_DISP_INFO_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PARSER_DISP_INFO_IN_LEN,
+		MC_CMD_GET_PARSER_DISP_INFO_OUT_LENMAX);
 	size_t matches_count;
 	size_t list_size;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PARSER_DISP_INFO;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PARSER_DISP_INFO_IN_LEN;
@@ -1057,12 +1054,15 @@ ef10_filter_insert_unicast(
 	efx_filter_spec_init_rx(&spec, EFX_FILTER_PRI_AUTO,
 	    filter_flags,
 	    eftp->eft_default_rxq);
-	efx_filter_spec_set_eth_local(&spec, EFX_FILTER_SPEC_VID_UNSPEC, addr);
+	rc = efx_filter_spec_set_eth_local(&spec, EFX_FILTER_SPEC_VID_UNSPEC,
+	    addr);
+	if (rc != 0)
+		goto fail1;
 
 	rc = ef10_filter_add_internal(enp, &spec, B_TRUE,
 	    &eftp->eft_unicst_filter_indexes[eftp->eft_unicst_filter_count]);
 	if (rc != 0)
-		goto fail1;
+		goto fail2;
 
 	eftp->eft_unicst_filter_count++;
 	EFSYS_ASSERT(eftp->eft_unicst_filter_count <=
@@ -1070,6 +1070,8 @@ ef10_filter_insert_unicast(
 
 	return (0);
 
+fail2:
+	EFSYS_PROBE(fail2);
 fail1:
 	EFSYS_PROBE1(fail1, efx_rc_t, rc);
 	return (rc);
@@ -1088,11 +1090,13 @@ ef10_filter_insert_all_unicast(
 	efx_filter_spec_init_rx(&spec, EFX_FILTER_PRI_AUTO,
 	    filter_flags,
 	    eftp->eft_default_rxq);
-	efx_filter_spec_set_uc_def(&spec);
+	rc = efx_filter_spec_set_uc_def(&spec);
+	if (rc != 0)
+		goto fail1;
 	rc = ef10_filter_add_internal(enp, &spec, B_TRUE,
 	    &eftp->eft_unicst_filter_indexes[eftp->eft_unicst_filter_count]);
 	if (rc != 0)
-		goto fail1;
+		goto fail2;
 
 	eftp->eft_unicst_filter_count++;
 	EFSYS_ASSERT(eftp->eft_unicst_filter_count <=
@@ -1100,6 +1104,8 @@ ef10_filter_insert_all_unicast(
 
 	return (0);
 
+fail2:
+	EFSYS_PROBE(fail2);
 fail1:
 	EFSYS_PROBE1(fail1, efx_rc_t, rc);
 	return (rc);
@@ -1141,9 +1147,21 @@ ef10_filter_insert_multicast_list(
 		    filter_flags,
 		    eftp->eft_default_rxq);
 
-		efx_filter_spec_set_eth_local(&spec,
+		rc = efx_filter_spec_set_eth_local(&spec,
 		    EFX_FILTER_SPEC_VID_UNSPEC,
 		    &addrs[i * EFX_MAC_ADDR_LEN]);
+		if (rc != 0) {
+			if (rollback == B_TRUE) {
+				/* Only stop upon failure if told to rollback */
+				goto rollback;
+			} else {
+				/*
+				 * Don't try to add a filter with a corrupt
+				 * specification.
+				 */
+				continue;
+			}
+		}
 
 		rc = ef10_filter_add_internal(enp, &spec, B_TRUE,
 					    &filter_index);
@@ -1166,8 +1184,12 @@ ef10_filter_insert_multicast_list(
 		    eftp->eft_default_rxq);
 
 		EFX_MAC_BROADCAST_ADDR_SET(addr);
-		efx_filter_spec_set_eth_local(&spec, EFX_FILTER_SPEC_VID_UNSPEC,
-		    addr);
+		rc = efx_filter_spec_set_eth_local(&spec,
+		    EFX_FILTER_SPEC_VID_UNSPEC, addr);
+		if ((rc != 0) && (rollback == B_TRUE)) {
+			/* Only stop upon failure if told to rollback */
+			goto rollback;
+		}
 
 		rc = ef10_filter_add_internal(enp, &spec, B_TRUE,
 					    &filter_index);
@@ -1215,12 +1237,14 @@ ef10_filter_insert_all_multicast(
 	efx_filter_spec_init_rx(&spec, EFX_FILTER_PRI_AUTO,
 	    filter_flags,
 	    eftp->eft_default_rxq);
-	efx_filter_spec_set_mc_def(&spec);
+	rc = efx_filter_spec_set_mc_def(&spec);
+	if (rc != 0)
+		goto fail1;
 
 	rc = ef10_filter_add_internal(enp, &spec, B_TRUE,
 	    &eftp->eft_mulcst_filter_indexes[0]);
 	if (rc != 0)
-		goto fail1;
+		goto fail2;
 
 	eftp->eft_mulcst_filter_count = 1;
 	eftp->eft_using_all_mulcst = B_TRUE;
@@ -1231,6 +1255,8 @@ ef10_filter_insert_all_multicast(
 
 	return (0);
 
+fail2:
+	EFSYS_PROBE(fail2);
 fail1:
 	EFSYS_PROBE1(fail1, efx_rc_t, rc);
 
@@ -1465,7 +1491,7 @@ ef10_filter_reconfigure(
 	/*
 	 * Insert or renew unicast filters.
 	 *
-	 * Frimware does not perform chaining on unicast filters. As traffic is
+	 * Firmware does not perform chaining on unicast filters. As traffic is
 	 * therefore only delivered to the first matching filter, we should
 	 * always insert the specific filter for our MAC address, to try and
 	 * ensure we get that traffic.
diff --git a/drivers/net/sfc/base/ef10_impl.h b/drivers/net/sfc/base/ef10_impl.h
index 8f9eb7a3..d573a81f 100644
--- a/drivers/net/sfc/base/ef10_impl.h
+++ b/drivers/net/sfc/base/ef10_impl.h
@@ -454,7 +454,7 @@ ef10_nvram_partn_write(
 	__in			efx_nic_t *enp,
 	__in			uint32_t partn,
 	__in			unsigned int offset,
-	__out_bcount(size)	caddr_t data,
+	__in_bcount(size)	caddr_t data,
 	__in			size_t size);
 
 extern	__checkReturn		efx_rc_t
diff --git a/drivers/net/sfc/base/ef10_intr.c b/drivers/net/sfc/base/ef10_intr.c
index 16be3d8c..db952d3d 100644
--- a/drivers/net/sfc/base/ef10_intr.c
+++ b/drivers/net/sfc/base/ef10_intr.c
@@ -75,8 +75,8 @@ efx_mcdi_trigger_interrupt(
 	__in		unsigned int level)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_TRIGGER_INTERRUPT_IN_LEN,
-			    MC_CMD_TRIGGER_INTERRUPT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_TRIGGER_INTERRUPT_IN_LEN,
+		MC_CMD_TRIGGER_INTERRUPT_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
@@ -87,7 +87,6 @@ efx_mcdi_trigger_interrupt(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_TRIGGER_INTERRUPT;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_TRIGGER_INTERRUPT_IN_LEN;
diff --git a/drivers/net/sfc/base/ef10_mac.c b/drivers/net/sfc/base/ef10_mac.c
index 488633f5..831c79df 100644
--- a/drivers/net/sfc/base/ef10_mac.c
+++ b/drivers/net/sfc/base/ef10_mac.c
@@ -99,11 +99,10 @@ efx_mcdi_vadapter_set_mac(
 {
 	efx_port_t *epp = &(enp->en_port);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_VADAPTOR_SET_MAC_IN_LEN,
-			    MC_CMD_VADAPTOR_SET_MAC_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_VADAPTOR_SET_MAC_IN_LEN,
+		MC_CMD_VADAPTOR_SET_MAC_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_VADAPTOR_SET_MAC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_VADAPTOR_SET_MAC_IN_LEN;
@@ -165,11 +164,10 @@ efx_mcdi_mtu_set(
 	__in		uint32_t mtu)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SET_MAC_EXT_IN_LEN,
-			    MC_CMD_SET_MAC_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SET_MAC_EXT_IN_LEN,
+		MC_CMD_SET_MAC_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_MAC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_MAC_EXT_IN_LEN;
@@ -202,11 +200,10 @@ efx_mcdi_mtu_get(
 	__out		size_t *mtu)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SET_MAC_EXT_IN_LEN,
-			    MC_CMD_SET_MAC_V2_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SET_MAC_EXT_IN_LEN,
+		MC_CMD_SET_MAC_V2_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_MAC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_MAC_EXT_IN_LEN;
@@ -298,11 +295,10 @@ ef10_mac_reconfigure(
 {
 	efx_port_t *epp = &(enp->en_port);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SET_MAC_IN_LEN,
-			    MC_CMD_SET_MAC_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SET_MAC_IN_LEN,
+		MC_CMD_SET_MAC_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_MAC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_MAC_IN_LEN;
@@ -435,7 +431,7 @@ ef10_mac_filter_default_rxq_clear(
 
 	ef10_filter_default_rxq_clear(enp);
 
-	efx_filter_reconfigure(enp, epp->ep_mac_addr,
+	(void) efx_filter_reconfigure(enp, epp->ep_mac_addr,
 				    epp->ep_all_unicst, epp->ep_mulcst,
 				    epp->ep_all_mulcst, epp->ep_brdcst,
 				    epp->ep_mulcst_addr_list,
@@ -612,7 +608,7 @@ ef10_mac_stats_update(
 	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_TX_LT64_PKTS, &value);
 	EFSYS_STAT_SET_QWORD(&(stat[EFX_MAC_TX_LE_64_PKTS]), &value);
 	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_TX_64_PKTS, &value);
-	EFSYS_STAT_SET_QWORD(&(stat[EFX_MAC_TX_LE_64_PKTS]), &value);
+	EFSYS_STAT_INCR_QWORD(&(stat[EFX_MAC_TX_LE_64_PKTS]), &value);
 
 	EF10_MAC_STAT_READ(esmp, MC_CMD_MAC_TX_65_TO_127_PKTS, &value);
 	EFSYS_STAT_SET_QWORD(&(stat[EFX_MAC_TX_65_TO_127_PKTS]), &value);
diff --git a/drivers/net/sfc/base/ef10_nic.c b/drivers/net/sfc/base/ef10_nic.c
index 58d1b0af..c92acea7 100644
--- a/drivers/net/sfc/base/ef10_nic.c
+++ b/drivers/net/sfc/base/ef10_nic.c
@@ -44,14 +44,13 @@ efx_mcdi_get_port_assignment(
 	__out		uint32_t *portp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PORT_ASSIGNMENT_IN_LEN,
-			    MC_CMD_GET_PORT_ASSIGNMENT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PORT_ASSIGNMENT_IN_LEN,
+		MC_CMD_GET_PORT_ASSIGNMENT_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
 		    enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PORT_ASSIGNMENT;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PORT_ASSIGNMENT_IN_LEN;
@@ -89,14 +88,13 @@ efx_mcdi_get_port_modes(
 	__out_opt	uint32_t *current_modep)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PORT_MODES_IN_LEN,
-			    MC_CMD_GET_PORT_MODES_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PORT_MODES_IN_LEN,
+		MC_CMD_GET_PORT_MODES_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
 		    enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PORT_MODES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PORT_MODES_IN_LEN;
@@ -196,13 +194,12 @@ efx_mcdi_vadaptor_alloc(
 	__in			uint32_t port_id)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_VADAPTOR_ALLOC_IN_LEN,
-			    MC_CMD_VADAPTOR_ALLOC_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_VADAPTOR_ALLOC_IN_LEN,
+		MC_CMD_VADAPTOR_ALLOC_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT3U(enp->en_vport_id, ==, EVB_PORT_ID_NULL);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_VADAPTOR_ALLOC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_VADAPTOR_ALLOC_IN_LEN;
@@ -235,11 +232,10 @@ efx_mcdi_vadaptor_free(
 	__in			uint32_t port_id)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_VADAPTOR_FREE_IN_LEN,
-			    MC_CMD_VADAPTOR_FREE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_VADAPTOR_FREE_IN_LEN,
+		MC_CMD_VADAPTOR_FREE_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_VADAPTOR_FREE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_VADAPTOR_FREE_IN_LEN;
@@ -269,14 +265,13 @@ efx_mcdi_get_mac_address_pf(
 	__out_ecount_opt(6)	uint8_t mac_addrp[6])
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_MAC_ADDRESSES_IN_LEN,
-			    MC_CMD_GET_MAC_ADDRESSES_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_MAC_ADDRESSES_IN_LEN,
+		MC_CMD_GET_MAC_ADDRESSES_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
 		    enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_MAC_ADDRESSES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_MAC_ADDRESSES_IN_LEN;
@@ -327,14 +322,13 @@ efx_mcdi_get_mac_address_vf(
 	__out_ecount_opt(6)	uint8_t mac_addrp[6])
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_VPORT_GET_MAC_ADDRESSES_IN_LEN,
-			    MC_CMD_VPORT_GET_MAC_ADDRESSES_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_VPORT_GET_MAC_ADDRESSES_IN_LEN,
+		MC_CMD_VPORT_GET_MAC_ADDRESSES_OUT_LENMAX);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
 		    enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_VPORT_GET_MAC_ADDRESSES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_VPORT_GET_MAC_ADDRESSES_IN_LEN;
@@ -391,14 +385,13 @@ efx_mcdi_get_clock(
 	__out		uint32_t *dpcpu_freqp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_CLOCK_IN_LEN,
-			    MC_CMD_GET_CLOCK_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_CLOCK_IN_LEN,
+		MC_CMD_GET_CLOCK_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON ||
 		    enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_CLOCK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_CLOCK_IN_LEN;
@@ -450,11 +443,10 @@ efx_mcdi_get_vector_cfg(
 	__out_opt	uint32_t *vf_nvecp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_VECTOR_CFG_IN_LEN,
-			    MC_CMD_GET_VECTOR_CFG_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_VECTOR_CFG_IN_LEN,
+		MC_CMD_GET_VECTOR_CFG_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_VECTOR_CFG;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_VECTOR_CFG_IN_LEN;
@@ -500,8 +492,8 @@ efx_mcdi_alloc_vis(
 	__out		uint32_t *vi_shiftp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_ALLOC_VIS_IN_LEN,
-			    MC_CMD_ALLOC_VIS_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_ALLOC_VIS_IN_LEN,
+		MC_CMD_ALLOC_VIS_EXT_OUT_LEN);
 	efx_rc_t rc;
 
 	if (vi_countp == NULL) {
@@ -509,7 +501,6 @@ efx_mcdi_alloc_vis(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_ALLOC_VIS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_ALLOC_VIS_IN_LEN;
@@ -592,8 +583,8 @@ efx_mcdi_alloc_piobuf(
 	__out		efx_piobuf_handle_t *handlep)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_ALLOC_PIOBUF_IN_LEN,
-			    MC_CMD_ALLOC_PIOBUF_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_ALLOC_PIOBUF_IN_LEN,
+		MC_CMD_ALLOC_PIOBUF_OUT_LEN);
 	efx_rc_t rc;
 
 	if (handlep == NULL) {
@@ -601,7 +592,6 @@ efx_mcdi_alloc_piobuf(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_ALLOC_PIOBUF;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_ALLOC_PIOBUF_IN_LEN;
@@ -640,11 +630,10 @@ efx_mcdi_free_piobuf(
 	__in		efx_piobuf_handle_t handle)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FREE_PIOBUF_IN_LEN,
-			    MC_CMD_FREE_PIOBUF_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FREE_PIOBUF_IN_LEN,
+		MC_CMD_FREE_PIOBUF_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FREE_PIOBUF;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FREE_PIOBUF_IN_LEN;
@@ -675,11 +664,10 @@ efx_mcdi_link_piobuf(
 	__in		efx_piobuf_handle_t handle)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_LINK_PIOBUF_IN_LEN,
-			    MC_CMD_LINK_PIOBUF_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LINK_PIOBUF_IN_LEN,
+		MC_CMD_LINK_PIOBUF_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LINK_PIOBUF;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LINK_PIOBUF_IN_LEN;
@@ -710,11 +698,10 @@ efx_mcdi_unlink_piobuf(
 	__in		uint32_t vi_index)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_UNLINK_PIOBUF_IN_LEN,
-			    MC_CMD_UNLINK_PIOBUF_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_UNLINK_PIOBUF_IN_LEN,
+		MC_CMD_UNLINK_PIOBUF_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_UNLINK_PIOBUF;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_UNLINK_PIOBUF_IN_LEN;
@@ -767,7 +754,7 @@ fail1:
 	for (i = 0; i < enp->en_arch.ef10.ena_piobuf_count; i++) {
 		handlep = &enp->en_arch.ef10.ena_piobuf_handle[i];
 
-		efx_mcdi_free_piobuf(enp, *handlep);
+		(void) efx_mcdi_free_piobuf(enp, *handlep);
 		*handlep = EFX_PIOBUF_HANDLE_INVALID;
 	}
 	enp->en_arch.ef10.ena_piobuf_count = 0;
@@ -784,7 +771,7 @@ ef10_nic_free_piobufs(
 	for (i = 0; i < enp->en_arch.ef10.ena_piobuf_count; i++) {
 		handlep = &enp->en_arch.ef10.ena_piobuf_handle[i];
 
-		efx_mcdi_free_piobuf(enp, *handlep);
+		(void) efx_mcdi_free_piobuf(enp, *handlep);
 		*handlep = EFX_PIOBUF_HANDLE_INVALID;
 	}
 	enp->en_arch.ef10.ena_piobuf_count = 0;
@@ -911,11 +898,10 @@ ef10_mcdi_get_pf_count(
 	__out		uint32_t *pf_countp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PF_COUNT_IN_LEN,
-			    MC_CMD_GET_PF_COUNT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PF_COUNT_IN_LEN,
+		MC_CMD_GET_PF_COUNT_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PF_COUNT;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PF_COUNT_IN_LEN;
@@ -1458,8 +1444,8 @@ ef10_nic_reset(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_ENTITY_RESET_IN_LEN,
-			    MC_CMD_ENTITY_RESET_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_ENTITY_RESET_IN_LEN,
+		MC_CMD_ENTITY_RESET_OUT_LEN);
 	efx_rc_t rc;
 
 	/* ef10_nic_reset() is called to recover from BADASSERT failures. */
@@ -1468,7 +1454,6 @@ ef10_nic_reset(
 	if ((rc = efx_mcdi_exit_assertion_handler(enp)) != 0)
 		goto fail2;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_ENTITY_RESET;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_ENTITY_RESET_IN_LEN;
diff --git a/drivers/net/sfc/base/ef10_nvram.c b/drivers/net/sfc/base/ef10_nvram.c
index 3f9d3750..75ac015d 100644
--- a/drivers/net/sfc/base/ef10_nvram.c
+++ b/drivers/net/sfc/base/ef10_nvram.c
@@ -1825,7 +1825,7 @@ ef10_nvram_partn_write_segment_tlv(
 		goto fail7;
 
 	/* Unlock the partition */
-	ef10_nvram_partn_unlock(enp, partn, NULL);
+	(void) ef10_nvram_partn_unlock(enp, partn, NULL);
 
 	EFSYS_KMEM_FREE(enp->en_esip, partn_size, partn_data);
 
@@ -1840,7 +1840,7 @@ fail5:
 fail4:
 	EFSYS_PROBE(fail4);
 
-	ef10_nvram_partn_unlock(enp, partn, NULL);
+	(void) ef10_nvram_partn_unlock(enp, partn, NULL);
 fail3:
 	EFSYS_PROBE(fail3);
 
@@ -1994,7 +1994,7 @@ ef10_nvram_partn_write(
 	__in			efx_nic_t *enp,
 	__in			uint32_t partn,
 	__in			unsigned int offset,
-	__out_bcount(size)	caddr_t data,
+	__in_bcount(size)	caddr_t data,
 	__in			size_t size)
 {
 	size_t chunk;
diff --git a/drivers/net/sfc/base/ef10_phy.c b/drivers/net/sfc/base/ef10_phy.c
index 81309f29..55403f7c 100644
--- a/drivers/net/sfc/base/ef10_phy.c
+++ b/drivers/net/sfc/base/ef10_phy.c
@@ -202,11 +202,10 @@ ef10_phy_get_link(
 	__out		ef10_link_state_t *elsp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_LINK_IN_LEN,
-			    MC_CMD_GET_LINK_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_LINK_IN_LEN,
+		MC_CMD_GET_LINK_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_LINK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_LINK_IN_LEN;
@@ -277,8 +276,8 @@ ef10_phy_reconfigure(
 {
 	efx_port_t *epp = &(enp->en_port);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SET_LINK_IN_LEN,
-			    MC_CMD_SET_LINK_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SET_LINK_IN_LEN,
+		MC_CMD_SET_LINK_OUT_LEN);
 	uint32_t cap_mask;
 	unsigned int led_mode;
 	unsigned int speed;
@@ -290,7 +289,6 @@ ef10_phy_reconfigure(
 	if (supported == B_FALSE)
 		goto out;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_LINK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_LINK_IN_LEN;
@@ -404,12 +402,11 @@ ef10_phy_verify(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PHY_STATE_IN_LEN,
-			    MC_CMD_GET_PHY_STATE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PHY_STATE_IN_LEN,
+		MC_CMD_GET_PHY_STATE_OUT_LEN);
 	uint32_t state;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PHY_STATE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PHY_STATE_IN_LEN;
@@ -523,22 +520,34 @@ ef10_bist_poll(
 	unsigned long *valuesp,
 	__in			size_t count)
 {
+	/*
+	 * MCDI_CTL_SDU_LEN_MAX_V1 is large enough cover all BIST results,
+	 * whilst not wasting stack.
+	 */
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_POLL_BIST_IN_LEN,
+		MCDI_CTL_SDU_LEN_MAX_V1);
 	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_POLL_BIST_IN_LEN,
-			    MCDI_CTL_SDU_LEN_MAX)];
 	uint32_t value_mask = 0;
 	uint32_t result;
 	efx_rc_t rc;
 
+	EFX_STATIC_ASSERT(MC_CMD_POLL_BIST_OUT_LEN <=
+	    MCDI_CTL_SDU_LEN_MAX_V1);
+	EFX_STATIC_ASSERT(MC_CMD_POLL_BIST_OUT_SFT9001_LEN <=
+	    MCDI_CTL_SDU_LEN_MAX_V1);
+	EFX_STATIC_ASSERT(MC_CMD_POLL_BIST_OUT_MRSFP_LEN <=
+	    MCDI_CTL_SDU_LEN_MAX_V1);
+	EFX_STATIC_ASSERT(MC_CMD_POLL_BIST_OUT_MEM_LEN <=
+	    MCDI_CTL_SDU_LEN_MAX_V1);
+
 	_NOTE(ARGUNUSED(type))
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_POLL_BIST;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_POLL_BIST_IN_LEN;
 	req.emr_out_buf = payload;
-	req.emr_out_length = MCDI_CTL_SDU_LEN_MAX;
+	req.emr_out_length = MCDI_CTL_SDU_LEN_MAX_V1;
 
 	efx_mcdi_execute(enp, &req);
 
diff --git a/drivers/net/sfc/base/ef10_rx.c b/drivers/net/sfc/base/ef10_rx.c
index 849f674c..c5f48b6c 100644
--- a/drivers/net/sfc/base/ef10_rx.c
+++ b/drivers/net/sfc/base/ef10_rx.c
@@ -47,8 +47,8 @@ efx_mcdi_init_rxq(
 	__in		uint32_t ps_bufsize)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_INIT_RXQ_EXT_IN_LEN,
-			    MC_CMD_INIT_RXQ_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_INIT_RXQ_EXT_IN_LEN,
+		MC_CMD_INIT_RXQ_EXT_OUT_LEN);
 	int npages = EFX_RXQ_NBUFS(size);
 	int i;
 	efx_qword_t *dma_addr;
@@ -65,7 +65,6 @@ efx_mcdi_init_rxq(
 	else
 		dma_mode = MC_CMD_INIT_RXQ_EXT_IN_SINGLE_PACKET;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_INIT_RXQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_INIT_RXQ_EXT_IN_LEN;
@@ -122,11 +121,10 @@ efx_mcdi_fini_rxq(
 	__in		uint32_t instance)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FINI_RXQ_IN_LEN,
-			    MC_CMD_FINI_RXQ_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FINI_RXQ_IN_LEN,
+		MC_CMD_FINI_RXQ_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FINI_RXQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FINI_RXQ_IN_LEN;
@@ -164,8 +162,8 @@ efx_mcdi_rss_context_alloc(
 	__out		uint32_t *rss_contextp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_RSS_CONTEXT_ALLOC_IN_LEN,
-			    MC_CMD_RSS_CONTEXT_ALLOC_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_RSS_CONTEXT_ALLOC_IN_LEN,
+		MC_CMD_RSS_CONTEXT_ALLOC_OUT_LEN);
 	uint32_t rss_context;
 	uint32_t context_type;
 	efx_rc_t rc;
@@ -187,7 +185,6 @@ efx_mcdi_rss_context_alloc(
 		goto fail2;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_RSS_CONTEXT_ALLOC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_RSS_CONTEXT_ALLOC_IN_LEN;
@@ -244,8 +241,8 @@ efx_mcdi_rss_context_free(
 	__in		uint32_t rss_context)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_RSS_CONTEXT_FREE_IN_LEN,
-			    MC_CMD_RSS_CONTEXT_FREE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_RSS_CONTEXT_FREE_IN_LEN,
+		MC_CMD_RSS_CONTEXT_FREE_OUT_LEN);
 	efx_rc_t rc;
 
 	if (rss_context == EF10_RSS_CONTEXT_INVALID) {
@@ -253,7 +250,6 @@ efx_mcdi_rss_context_free(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_RSS_CONTEXT_FREE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_RSS_CONTEXT_FREE_IN_LEN;
@@ -288,8 +284,8 @@ efx_mcdi_rss_context_set_flags(
 	__in		efx_rx_hash_type_t type)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_RSS_CONTEXT_SET_FLAGS_IN_LEN,
-			    MC_CMD_RSS_CONTEXT_SET_FLAGS_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_RSS_CONTEXT_SET_FLAGS_IN_LEN,
+		MC_CMD_RSS_CONTEXT_SET_FLAGS_OUT_LEN);
 	efx_rc_t rc;
 
 	if (rss_context == EF10_RSS_CONTEXT_INVALID) {
@@ -297,7 +293,6 @@ efx_mcdi_rss_context_set_flags(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_RSS_CONTEXT_SET_FLAGS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_RSS_CONTEXT_SET_FLAGS_IN_LEN;
@@ -344,8 +339,8 @@ efx_mcdi_rss_context_set_key(
 	__in		size_t n)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_RSS_CONTEXT_SET_KEY_IN_LEN,
-			    MC_CMD_RSS_CONTEXT_SET_KEY_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_RSS_CONTEXT_SET_KEY_IN_LEN,
+		MC_CMD_RSS_CONTEXT_SET_KEY_OUT_LEN);
 	efx_rc_t rc;
 
 	if (rss_context == EF10_RSS_CONTEXT_INVALID) {
@@ -353,7 +348,6 @@ efx_mcdi_rss_context_set_key(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_RSS_CONTEXT_SET_KEY;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_RSS_CONTEXT_SET_KEY_IN_LEN;
@@ -401,8 +395,8 @@ efx_mcdi_rss_context_set_table(
 	__in		size_t n)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_RSS_CONTEXT_SET_TABLE_IN_LEN,
-			    MC_CMD_RSS_CONTEXT_SET_TABLE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_RSS_CONTEXT_SET_TABLE_IN_LEN,
+		MC_CMD_RSS_CONTEXT_SET_TABLE_OUT_LEN);
 	uint8_t *req_table;
 	int i, rc;
 
@@ -411,7 +405,6 @@ efx_mcdi_rss_context_set_table(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_RSS_CONTEXT_SET_TABLE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_RSS_CONTEXT_SET_TABLE_IN_LEN;
diff --git a/drivers/net/sfc/base/ef10_tx.c b/drivers/net/sfc/base/ef10_tx.c
index 211d2655..32de4a37 100644
--- a/drivers/net/sfc/base/ef10_tx.c
+++ b/drivers/net/sfc/base/ef10_tx.c
@@ -55,8 +55,8 @@ efx_mcdi_init_txq(
 	__in		efsys_mem_t *esmp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_INIT_TXQ_IN_LEN(EFX_TXQ_MAX_BUFS),
-			    MC_CMD_INIT_TXQ_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_INIT_TXQ_IN_LEN(EFX_TXQ_MAX_BUFS),
+		MC_CMD_INIT_TXQ_OUT_LEN);
 	efx_qword_t *dma_addr;
 	uint64_t addr;
 	int npages;
@@ -72,7 +72,6 @@ efx_mcdi_init_txq(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_INIT_TXQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_INIT_TXQ_IN_LEN(npages);
@@ -133,11 +132,10 @@ efx_mcdi_fini_txq(
 	__in		uint32_t instance)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FINI_TXQ_IN_LEN,
-			    MC_CMD_FINI_TXQ_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FINI_TXQ_IN_LEN,
+		MC_CMD_FINI_TXQ_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FINI_TXQ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FINI_TXQ_IN_LEN;
@@ -286,7 +284,7 @@ ef10_tx_qpio_enable(
 
 fail3:
 	EFSYS_PROBE(fail3);
-	ef10_nic_pio_free(enp, etp->et_pio_bufnum, etp->et_pio_blknum);
+	(void) ef10_nic_pio_free(enp, etp->et_pio_bufnum, etp->et_pio_blknum);
 fail2:
 	EFSYS_PROBE(fail2);
 	etp->et_pio_size = 0;
@@ -304,10 +302,12 @@ ef10_tx_qpio_disable(
 
 	if (etp->et_pio_size != 0) {
 		/* Unlink the piobuf from this TXQ */
-		ef10_nic_pio_unlink(enp, etp->et_index);
+		if (ef10_nic_pio_unlink(enp, etp->et_index) != 0)
+			return;
 
 		/* Free the sub-allocated PIO block */
-		ef10_nic_pio_free(enp, etp->et_pio_bufnum, etp->et_pio_blknum);
+		(void) ef10_nic_pio_free(enp, etp->et_pio_bufnum,
+		    etp->et_pio_blknum);
 		etp->et_pio_size = 0;
 		etp->et_pio_write_offset = 0;
 	}
diff --git a/drivers/net/sfc/base/efx_impl.h b/drivers/net/sfc/base/efx_impl.h
index 53fa37ac..fc569601 100644
--- a/drivers/net/sfc/base/efx_impl.h
+++ b/drivers/net/sfc/base/efx_impl.h
@@ -296,7 +296,6 @@ typedef struct efx_port_s {
 	uint32_t		ep_default_adv_cap_mask;
 	uint32_t		ep_phy_cap_mask;
 	boolean_t		ep_mac_drain;
-	boolean_t		ep_mac_stats_pending;
 #if EFSYS_OPT_BIST
 	efx_bist_type_t		ep_current_bist;
 #endif
@@ -556,7 +555,7 @@ efx_mcdi_nvram_write(
 	__in			efx_nic_t *enp,
 	__in			uint32_t partn,
 	__in			uint32_t offset,
-	__out_bcount(size)	caddr_t data,
+	__in_bcount(size)	caddr_t data,
 	__in			size_t size);
 
 	__checkReturn		efx_rc_t
diff --git a/drivers/net/sfc/base/efx_lic.c b/drivers/net/sfc/base/efx_lic.c
index 2cd05cc8..7ad6ed2a 100644
--- a/drivers/net/sfc/base/efx_lic.c
+++ b/drivers/net/sfc/base/efx_lic.c
@@ -340,12 +340,11 @@ efx_mcdi_fc_license_update_license(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MC_CMD_FC_IN_LICENSE_LEN];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FC_IN_LICENSE_LEN, 0);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_SIENA);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FC_IN_LICENSE_LEN;
@@ -386,13 +385,12 @@ efx_mcdi_fc_license_get_key_stats(
 	__out		efx_key_stats_t *eksp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_FC_IN_LICENSE_LEN,
-			    MC_CMD_FC_OUT_LICENSE_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_FC_IN_LICENSE_LEN,
+		MC_CMD_FC_OUT_LICENSE_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_SIENA);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_FC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_FC_IN_LICENSE_LEN;
@@ -711,8 +709,8 @@ efx_mcdi_licensed_app_state(
 	__out		boolean_t *licensedp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_LICENSED_APP_STATE_IN_LEN,
-			    MC_CMD_GET_LICENSED_APP_STATE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_LICENSED_APP_STATE_IN_LEN,
+		MC_CMD_GET_LICENSED_APP_STATE_OUT_LEN);
 	uint32_t app_state;
 	efx_rc_t rc;
 
@@ -724,7 +722,6 @@ efx_mcdi_licensed_app_state(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_LICENSED_APP_STATE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_LICENSED_APP_STATE_IN_LEN;
@@ -770,12 +767,11 @@ efx_mcdi_licensing_update_licenses(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MC_CMD_LICENSING_IN_LEN];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LICENSING_IN_LEN, 0);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LICENSING;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LICENSING_IN_LEN;
@@ -813,13 +809,12 @@ efx_mcdi_licensing_get_key_stats(
 	__out		efx_key_stats_t *eksp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_LICENSING_IN_LEN,
-			    MC_CMD_LICENSING_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LICENSING_IN_LEN,
+		MC_CMD_LICENSING_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_HUNTINGTON);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LICENSING;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LICENSING_IN_LEN;
@@ -877,12 +872,11 @@ efx_mcdi_licensing_v3_update_licenses(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MC_CMD_LICENSING_V3_IN_LEN];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LICENSING_V3_IN_LEN, 0);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LICENSING_V3;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LICENSING_V3_IN_LEN;
@@ -913,13 +907,12 @@ efx_mcdi_licensing_v3_report_license(
 	__out		efx_key_stats_t *eksp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_LICENSING_V3_IN_LEN,
-			    MC_CMD_LICENSING_V3_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LICENSING_V3_IN_LEN,
+		MC_CMD_LICENSING_V3_OUT_LEN);
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LICENSING_V3;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LICENSING_V3_IN_LEN;
@@ -976,14 +969,13 @@ efx_mcdi_licensing_v3_app_state(
 	__out		boolean_t *licensedp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_LICENSED_V3_APP_STATE_IN_LEN,
-			    MC_CMD_GET_LICENSED_V3_APP_STATE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_LICENSED_V3_APP_STATE_IN_LEN,
+		MC_CMD_GET_LICENSED_V3_APP_STATE_OUT_LEN);
 	uint32_t app_state;
 	efx_rc_t rc;
 
 	EFSYS_ASSERT(enp->en_family == EFX_FAMILY_MEDFORD);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_LICENSED_V3_APP_STATE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_LICENSED_V3_APP_STATE_IN_LEN;
@@ -1034,27 +1026,15 @@ efx_mcdi_licensing_v3_get_id(
 			uint8_t *bufferp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_LICENSING_GET_ID_V3_IN_LEN,
-			    MC_CMD_LICENSING_GET_ID_V3_OUT_LENMIN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LICENSING_GET_ID_V3_IN_LEN,
+		MC_CMD_LICENSING_GET_ID_V3_OUT_LENMAX);
 	efx_rc_t rc;
 
 	req.emr_cmd = MC_CMD_LICENSING_GET_ID_V3;
-
-	if (bufferp == NULL) {
-		/* Request id type and length only */
-		req.emr_in_buf = bufferp;
-		req.emr_in_length = MC_CMD_LICENSING_GET_ID_V3_IN_LEN;
-		req.emr_out_buf = bufferp;
-		req.emr_out_length = MC_CMD_LICENSING_GET_ID_V3_OUT_LENMIN;
-		(void) memset(payload, 0, sizeof (payload));
-	} else {
-		/* Request full buffer */
-		req.emr_in_buf = bufferp;
-		req.emr_in_length = MC_CMD_LICENSING_GET_ID_V3_IN_LEN;
-		req.emr_out_buf = bufferp;
-		req.emr_out_length = MIN(buffer_size, MC_CMD_LICENSING_GET_ID_V3_OUT_LENMAX);
-		(void) memset(bufferp, 0, req.emr_out_length);
-	}
+	req.emr_in_buf = payload;
+	req.emr_in_length = MC_CMD_LICENSING_GET_ID_V3_IN_LEN;
+	req.emr_out_buf = payload;
+	req.emr_out_length = MC_CMD_LICENSING_GET_ID_V3_OUT_LENMAX;
 
 	efx_mcdi_execute_quiet(enp, &req);
 
@@ -1071,18 +1051,10 @@ efx_mcdi_licensing_v3_get_id(
 	*typep = MCDI_OUT_DWORD(req, LICENSING_GET_ID_V3_OUT_LICENSE_TYPE);
 	*lengthp = MCDI_OUT_DWORD(req, LICENSING_GET_ID_V3_OUT_LICENSE_ID_LENGTH);
 
-	if (bufferp == NULL) {
-		/* modify length requirements to indicate to caller the extra buffering
-		** needed to read the complete output.
-		*/
-		*lengthp += MC_CMD_LICENSING_GET_ID_V3_OUT_LENMIN;
-	} else {
-		/* Shift ID down to start of buffer */
-		memmove(bufferp,
-		    bufferp + MC_CMD_LICENSING_GET_ID_V3_OUT_LICENSE_ID_OFST,
-		    *lengthp);
-		memset(bufferp + (*lengthp), 0,
-		    MC_CMD_LICENSING_GET_ID_V3_OUT_LICENSE_ID_OFST);
+	if (bufferp != NULL) {
+		memcpy(bufferp,
+		    payload + MC_CMD_LICENSING_GET_ID_V3_OUT_LICENSE_ID_OFST,
+		    MIN(buffer_size, *lengthp));
 	}
 
 	return (0);
diff --git a/drivers/net/sfc/base/efx_mac.c b/drivers/net/sfc/base/efx_mac.c
index 752e7205..0cf27317 100644
--- a/drivers/net/sfc/base/efx_mac.c
+++ b/drivers/net/sfc/base/efx_mac.c
@@ -751,16 +751,9 @@ efx_mac_stats_upload(
 	EFSYS_ASSERT3U(enp->en_mod_flags, &, EFX_MOD_PORT);
 	EFSYS_ASSERT(emop != NULL);
 
-	/*
-	 * Don't assert !ep_mac_stats_pending, because the client might
-	 * have failed to finalise statistics when previously stopping
-	 * the port.
-	 */
 	if ((rc = emop->emo_stats_upload(enp, esmp)) != 0)
 		goto fail1;
 
-	epp->ep_mac_stats_pending = B_TRUE;
-
 	return (0);
 
 fail1:
@@ -820,8 +813,6 @@ efx_mac_stats_update(
 	EFSYS_ASSERT(emop != NULL);
 
 	rc = emop->emo_stats_update(enp, esmp, essp, generationp);
-	if (rc == 0)
-		epp->ep_mac_stats_pending = B_FALSE;
 
 	return (rc);
 }
diff --git a/drivers/net/sfc/base/efx_mcdi.c b/drivers/net/sfc/base/efx_mcdi.c
index c61b943c..098e2364 100644
--- a/drivers/net/sfc/base/efx_mcdi.c
+++ b/drivers/net/sfc/base/efx_mcdi.c
@@ -916,10 +916,10 @@ efx_mcdi_version(
 	__out_opt		efx_mcdi_boot_t *statusp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MAX(MC_CMD_GET_VERSION_IN_LEN,
-				MC_CMD_GET_VERSION_OUT_LEN),
-			    MAX(MC_CMD_GET_BOOT_STATUS_IN_LEN,
-				MC_CMD_GET_BOOT_STATUS_OUT_LEN))];
+	EFX_MCDI_DECLARE_BUF(payload,
+		MAX(MC_CMD_GET_VERSION_IN_LEN, MC_CMD_GET_BOOT_STATUS_IN_LEN),
+		MAX(MC_CMD_GET_VERSION_OUT_LEN,
+			MC_CMD_GET_BOOT_STATUS_OUT_LEN));
 	efx_word_t *ver_words;
 	uint16_t version[4];
 	uint32_t build;
@@ -928,7 +928,6 @@ efx_mcdi_version(
 
 	EFSYS_ASSERT3U(enp->en_features, &, EFX_FEATURE_MCDI);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_VERSION;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_VERSION_IN_LEN;
@@ -969,7 +968,6 @@ version:
 		goto out;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_BOOT_STATUS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_BOOT_STATUS_IN_LEN;
@@ -1034,12 +1032,11 @@ efx_mcdi_get_capabilities(
 	__out_opt	uint32_t *tso2ncp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_CAPABILITIES_IN_LEN,
-			    MC_CMD_GET_CAPABILITIES_V2_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_CAPABILITIES_IN_LEN,
+		MC_CMD_GET_CAPABILITIES_V2_OUT_LEN);
 	boolean_t v2_capable;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_CAPABILITIES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_CAPABILITIES_IN_LEN;
@@ -1102,7 +1099,8 @@ efx_mcdi_do_reboot(
 	__in		efx_nic_t *enp,
 	__in		boolean_t after_assertion)
 {
-	uint8_t payload[MAX(MC_CMD_REBOOT_IN_LEN, MC_CMD_REBOOT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_REBOOT_IN_LEN,
+		MC_CMD_REBOOT_OUT_LEN);
 	efx_mcdi_req_t req;
 	efx_rc_t rc;
 
@@ -1115,7 +1113,6 @@ efx_mcdi_do_reboot(
 	 */
 	EFSYS_ASSERT3U(enp->en_magic, ==, EFX_NIC_MAGIC);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_REBOOT;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_REBOOT_IN_LEN;
@@ -1166,8 +1163,8 @@ efx_mcdi_read_assertion(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_ASSERTS_IN_LEN,
-			    MC_CMD_GET_ASSERTS_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_ASSERTS_IN_LEN,
+		MC_CMD_GET_ASSERTS_OUT_LEN);
 	const char *reason;
 	unsigned int flags;
 	unsigned int index;
@@ -1268,11 +1265,10 @@ efx_mcdi_drv_attach(
 	__in		boolean_t attach)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_DRV_ATTACH_IN_LEN,
-			    MC_CMD_DRV_ATTACH_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_DRV_ATTACH_IN_LEN,
+		MC_CMD_DRV_ATTACH_EXT_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_DRV_ATTACH;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_DRV_ATTACH_IN_LEN;
@@ -1319,11 +1315,10 @@ efx_mcdi_get_board_cfg(
 {
 	efx_mcdi_iface_t *emip = &(enp->en_mcdi.em_emip);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_BOARD_CFG_IN_LEN,
-			    MC_CMD_GET_BOARD_CFG_OUT_LENMIN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_BOARD_CFG_IN_LEN,
+		MC_CMD_GET_BOARD_CFG_OUT_LENMIN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_BOARD_CFG;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_BOARD_CFG_IN_LEN;
@@ -1399,11 +1394,10 @@ efx_mcdi_get_resource_limits(
 	__out_opt	uint32_t *ntxqp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_RESOURCE_LIMITS_IN_LEN,
-			    MC_CMD_GET_RESOURCE_LIMITS_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_RESOURCE_LIMITS_IN_LEN,
+		MC_CMD_GET_RESOURCE_LIMITS_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_RESOURCE_LIMITS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_RESOURCE_LIMITS_IN_LEN;
@@ -1446,11 +1440,10 @@ efx_mcdi_get_phy_cfg(
 	efx_port_t *epp = &(enp->en_port);
 	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PHY_CFG_IN_LEN,
-			    MC_CMD_GET_PHY_CFG_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PHY_CFG_IN_LEN,
+		MC_CMD_GET_PHY_CFG_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PHY_CFG;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PHY_CFG_IN_LEN;
@@ -1687,11 +1680,10 @@ efx_mcdi_bist_start(
 	__in			efx_bist_type_t type)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_START_BIST_IN_LEN,
-			    MC_CMD_START_BIST_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_START_BIST_IN_LEN,
+		MC_CMD_START_BIST_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_START_BIST;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_START_BIST_IN_LEN;
@@ -1750,11 +1742,10 @@ efx_mcdi_log_ctrl(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_LOG_CTRL_IN_LEN,
-			    MC_CMD_LOG_CTRL_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_LOG_CTRL_IN_LEN,
+		MC_CMD_LOG_CTRL_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_LOG_CTRL;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_LOG_CTRL_IN_LEN;
@@ -1799,8 +1790,8 @@ efx_mcdi_mac_stats(
 	__in		uint16_t period_ms)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_MAC_STATS_IN_LEN,
-			    MC_CMD_MAC_STATS_OUT_DMA_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_MAC_STATS_IN_LEN,
+		MC_CMD_MAC_STATS_OUT_DMA_LEN);
 	int clear = (action == EFX_STATS_CLEAR);
 	int upload = (action == EFX_STATS_UPLOAD);
 	int enable = (action == EFX_STATS_ENABLE_NOEVENTS);
@@ -1808,7 +1799,6 @@ efx_mcdi_mac_stats(
 	int disable = (action == EFX_STATS_DISABLE);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_MAC_STATS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_MAC_STATS_IN_LEN;
@@ -1958,11 +1948,10 @@ efx_mcdi_get_function_info(
 	__out_opt		uint32_t *vfp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_FUNCTION_INFO_IN_LEN,
-			    MC_CMD_GET_FUNCTION_INFO_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_FUNCTION_INFO_IN_LEN,
+		MC_CMD_GET_FUNCTION_INFO_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_FUNCTION_INFO;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_FUNCTION_INFO_IN_LEN;
@@ -2003,11 +1992,10 @@ efx_mcdi_privilege_mask(
 	__out			uint32_t *maskp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_PRIVILEGE_MASK_IN_LEN,
-			    MC_CMD_PRIVILEGE_MASK_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_PRIVILEGE_MASK_IN_LEN,
+		MC_CMD_PRIVILEGE_MASK_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_PRIVILEGE_MASK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_PRIVILEGE_MASK_IN_LEN;
@@ -2052,11 +2040,10 @@ efx_mcdi_set_workaround(
 	__out_opt		uint32_t *flagsp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_WORKAROUND_IN_LEN,
-			    MC_CMD_WORKAROUND_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_WORKAROUND_IN_LEN,
+		MC_CMD_WORKAROUND_EXT_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_WORKAROUND;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_WORKAROUND_IN_LEN;
@@ -2096,10 +2083,9 @@ efx_mcdi_get_workarounds(
 	__out_opt		uint32_t *enabledp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MC_CMD_GET_WORKAROUNDS_OUT_LEN];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_WORKAROUNDS_OUT_LEN, 0);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_WORKAROUNDS;
 	req.emr_in_buf = NULL;
 	req.emr_in_length = 0;
@@ -2145,14 +2131,13 @@ efx_mcdi_get_phy_media_info(
 	__out_bcount(len)	uint8_t *data)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PHY_MEDIA_INFO_IN_LEN,
-			    MC_CMD_GET_PHY_MEDIA_INFO_OUT_LEN(
-				EFX_PHY_MEDIA_INFO_PAGE_SIZE))];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PHY_MEDIA_INFO_IN_LEN,
+		MC_CMD_GET_PHY_MEDIA_INFO_OUT_LEN(
+			EFX_PHY_MEDIA_INFO_PAGE_SIZE));
 	efx_rc_t rc;
 
 	EFSYS_ASSERT((uint32_t)offset + len <= EFX_PHY_MEDIA_INFO_PAGE_SIZE);
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PHY_MEDIA_INFO;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PHY_MEDIA_INFO_IN_LEN;
diff --git a/drivers/net/sfc/base/efx_mcdi.h b/drivers/net/sfc/base/efx_mcdi.h
index 21727713..1f355c02 100644
--- a/drivers/net/sfc/base/efx_mcdi.h
+++ b/drivers/net/sfc/base/efx_mcdi.h
@@ -400,6 +400,17 @@ efx_mcdi_phy_module_get_info(
 	(((mask) & (MC_CMD_PRIVILEGE_MASK_IN_GRP_ ## priv)) ==		\
 	(MC_CMD_PRIVILEGE_MASK_IN_GRP_ ## priv))
 
+/*
+ * The buffer size must be a multiple of dword to ensure that MCDI works
+ * properly with Siena based boards (which use on-chip buffer). Also, it
+ * should be at minimum the size of two dwords to allow space for extended
+ * error responses if the request/response buffer sizes are smaller.
+ */
+#define	EFX_MCDI_DECLARE_BUF(_name, _in_len, _out_len)			\
+	uint8_t _name[P2ROUNDUP(MAX(MAX(_in_len, _out_len),		\
+				    (2 * sizeof (efx_dword_t))),	\
+				sizeof (efx_dword_t))] = {0}
+
 typedef enum efx_mcdi_feature_id_e {
 	EFX_MCDI_FEATURE_FW_UPDATE = 0,
 	EFX_MCDI_FEATURE_LINK_CONTROL,
diff --git a/drivers/net/sfc/base/efx_nic.c b/drivers/net/sfc/base/efx_nic.c
index 76caa744..5513ef22 100644
--- a/drivers/net/sfc/base/efx_nic.c
+++ b/drivers/net/sfc/base/efx_nic.c
@@ -587,7 +587,7 @@ efx_nic_reset(
 	 */
 	mod_flags = enp->en_mod_flags;
 	mod_flags &= ~(EFX_MOD_MCDI | EFX_MOD_PROBE | EFX_MOD_NVRAM |
-		    EFX_MOD_VPD | EFX_MOD_MON);
+	    EFX_MOD_VPD | EFX_MOD_MON);
 	EFSYS_ASSERT3U(mod_flags, ==, 0);
 	if (mod_flags != 0) {
 		rc = EINVAL;
@@ -612,6 +612,7 @@ efx_nic_cfg_get(
 	__in		efx_nic_t *enp)
 {
 	EFSYS_ASSERT3U(enp->en_magic, ==, EFX_NIC_MAGIC);
+	EFSYS_ASSERT3U(enp->en_mod_flags, &, EFX_MOD_PROBE);
 
 	return (&(enp->en_nic_cfg));
 }
@@ -933,13 +934,12 @@ efx_mcdi_get_loopback_modes(
 {
 	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_LOOPBACK_MODES_IN_LEN,
-			    MC_CMD_GET_LOOPBACK_MODES_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_LOOPBACK_MODES_IN_LEN,
+		MC_CMD_GET_LOOPBACK_MODES_OUT_LEN);
 	efx_qword_t mask;
 	efx_qword_t modes;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_LOOPBACK_MODES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_LOOPBACK_MODES_IN_LEN;
diff --git a/drivers/net/sfc/base/efx_nvram.c b/drivers/net/sfc/base/efx_nvram.c
index 6ee2a71d..0191acb3 100644
--- a/drivers/net/sfc/base/efx_nvram.c
+++ b/drivers/net/sfc/base/efx_nvram.c
@@ -503,12 +503,11 @@ efx_mcdi_nvram_partitions(
 	__out			unsigned int *npartnp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_PARTITIONS_IN_LEN,
-			    MC_CMD_NVRAM_PARTITIONS_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_PARTITIONS_IN_LEN,
+		MC_CMD_NVRAM_PARTITIONS_OUT_LENMAX);
 	unsigned int npartn;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_PARTITIONS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_PARTITIONS_IN_LEN;
@@ -566,11 +565,10 @@ efx_mcdi_nvram_metadata(
 	__in			size_t size)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_METADATA_IN_LEN,
-			    MC_CMD_NVRAM_METADATA_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_METADATA_IN_LEN,
+		MC_CMD_NVRAM_METADATA_OUT_LENMAX);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_METADATA;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_METADATA_IN_LEN;
@@ -656,12 +654,11 @@ efx_mcdi_nvram_info(
 	__out_opt		uint32_t *erase_sizep,
 	__out_opt		uint32_t *write_sizep)
 {
-	uint8_t payload[MAX(MC_CMD_NVRAM_INFO_IN_LEN,
-			    MC_CMD_NVRAM_INFO_V2_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_INFO_IN_LEN,
+		MC_CMD_NVRAM_INFO_V2_OUT_LEN);
 	efx_mcdi_req_t req;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_INFO;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_INFO_IN_LEN;
@@ -717,12 +714,11 @@ efx_mcdi_nvram_update_start(
 	__in			efx_nic_t *enp,
 	__in			uint32_t partn)
 {
-	uint8_t payload[MAX(MC_CMD_NVRAM_UPDATE_START_V2_IN_LEN,
-			    MC_CMD_NVRAM_UPDATE_START_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_UPDATE_START_V2_IN_LEN,
+		MC_CMD_NVRAM_UPDATE_START_OUT_LEN);
 	efx_mcdi_req_t req;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_UPDATE_START;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_UPDATE_START_V2_IN_LEN;
@@ -759,8 +755,8 @@ efx_mcdi_nvram_read(
 	__in			uint32_t mode)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_READ_IN_V2_LEN,
-			    MC_CMD_NVRAM_READ_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_READ_IN_V2_LEN,
+		MC_CMD_NVRAM_READ_OUT_LENMAX);
 	efx_rc_t rc;
 
 	if (size > MC_CMD_NVRAM_READ_OUT_LENMAX) {
@@ -768,7 +764,6 @@ efx_mcdi_nvram_read(
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_READ;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_READ_IN_V2_LEN;
@@ -814,11 +809,10 @@ efx_mcdi_nvram_erase(
 	__in			size_t size)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_ERASE_IN_LEN,
-			    MC_CMD_NVRAM_ERASE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_ERASE_IN_LEN,
+		MC_CMD_NVRAM_ERASE_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_ERASE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_ERASE_IN_LEN;
@@ -854,27 +848,31 @@ efx_mcdi_nvram_write(
 	__in			efx_nic_t *enp,
 	__in			uint32_t partn,
 	__in			uint32_t offset,
-	__out_bcount(size)	caddr_t data,
+	__in_bcount(size)	caddr_t data,
 	__in			size_t size)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MCDI_CTL_SDU_LEN_MAX_V1,
-			    MCDI_CTL_SDU_LEN_MAX_V2)];
+	uint8_t *payload;
 	efx_rc_t rc;
 	size_t max_data_size;
+	size_t payload_len = enp->en_nic_cfg.enc_mcdi_max_payload_length;
 
-	max_data_size = enp->en_nic_cfg.enc_mcdi_max_payload_length
-	    - MC_CMD_NVRAM_WRITE_IN_LEN(0);
-	EFSYS_ASSERT3U(enp->en_nic_cfg.enc_mcdi_max_payload_length, >, 0);
-	EFSYS_ASSERT3U(max_data_size, <,
-		    enp->en_nic_cfg.enc_mcdi_max_payload_length);
+	max_data_size = payload_len - MC_CMD_NVRAM_WRITE_IN_LEN(0);
+	EFSYS_ASSERT3U(payload_len, >, 0);
+	EFSYS_ASSERT3U(max_data_size, <, payload_len);
 
 	if (size > max_data_size) {
 		rc = EINVAL;
 		goto fail1;
 	}
 
-	(void) memset(payload, 0, sizeof (payload));
+	EFSYS_KMEM_ALLOC(enp->en_esip, payload_len, payload);
+	if (payload == NULL) {
+		rc = ENOMEM;
+		goto fail2;
+	}
+
+	(void) memset(payload, 0, payload_len);
 	req.emr_cmd = MC_CMD_NVRAM_WRITE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_WRITE_IN_LEN(size);
@@ -892,11 +890,16 @@ efx_mcdi_nvram_write(
 
 	if (req.emr_rc != 0) {
 		rc = req.emr_rc;
-		goto fail2;
+		goto fail3;
 	}
 
+	EFSYS_KMEM_FREE(enp->en_esip, payload_len, payload);
+
 	return (0);
 
+fail3:
+	EFSYS_PROBE(fail3);
+	EFSYS_KMEM_FREE(enp->en_esip, payload_len, payload);
 fail2:
 	EFSYS_PROBE(fail2);
 fail1:
@@ -919,12 +922,11 @@ efx_mcdi_nvram_update_finish(
 {
 	const efx_nic_cfg_t *encp = &enp->en_nic_cfg;
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_UPDATE_FINISH_V2_IN_LEN,
-			    MC_CMD_NVRAM_UPDATE_FINISH_V2_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_UPDATE_FINISH_V2_IN_LEN,
+		MC_CMD_NVRAM_UPDATE_FINISH_V2_OUT_LEN);
 	uint32_t result = 0; /* FIXME: use MC_CMD_NVRAM_VERIFY_RC_UNKNOWN */
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_UPDATE_FINISH;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_UPDATE_FINISH_V2_IN_LEN;
@@ -991,12 +993,11 @@ efx_mcdi_nvram_test(
 	__in			uint32_t partn)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_TEST_IN_LEN,
-			    MC_CMD_NVRAM_TEST_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_TEST_IN_LEN,
+		MC_CMD_NVRAM_TEST_OUT_LEN);
 	int result;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_TEST;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_TEST_IN_LEN;
diff --git a/drivers/net/sfc/base/efx_phy.c b/drivers/net/sfc/base/efx_phy.c
index 752cd52e..af1ad981 100644
--- a/drivers/net/sfc/base/efx_phy.c
+++ b/drivers/net/sfc/base/efx_phy.c
@@ -309,7 +309,7 @@ efx_phy_module_get_info(
 	EFSYS_ASSERT3U(enp->en_magic, ==, EFX_NIC_MAGIC);
 	EFSYS_ASSERT(data != NULL);
 
-	if ((uint32_t)offset + len > 0xff) {
+	if ((uint32_t)offset + len > 0x100) {
 		rc = EINVAL;
 		goto fail1;
 	}
diff --git a/drivers/net/sfc/base/efx_port.c b/drivers/net/sfc/base/efx_port.c
index ec8a1575..7584e5a8 100644
--- a/drivers/net/sfc/base/efx_port.c
+++ b/drivers/net/sfc/base/efx_port.c
@@ -61,7 +61,7 @@ efx_port_init(
 	epp->ep_emop->emo_reconfigure(enp);
 
 	/* Pick up current phy capababilities */
-	efx_port_poll(enp, NULL);
+	(void) efx_port_poll(enp, NULL);
 
 	/*
 	 * Turn on the PHY if available, otherwise reset it, and
@@ -109,7 +109,6 @@ efx_port_poll(
 	EFSYS_ASSERT3U(enp->en_mod_flags, &, EFX_MOD_PORT);
 
 	EFSYS_ASSERT(emop != NULL);
-	EFSYS_ASSERT(!epp->ep_mac_stats_pending);
 
 	if (link_modep == NULL)
 		link_modep = &ignore_link_mode;
diff --git a/drivers/net/sfc/base/mcdi_mon.c b/drivers/net/sfc/base/mcdi_mon.c
index c5360c31..8fb4113c 100644
--- a/drivers/net/sfc/base/mcdi_mon.c
+++ b/drivers/net/sfc/base/mcdi_mon.c
@@ -30,6 +30,7 @@
 
 #include "efx.h"
 #include "efx_impl.h"
+#include "mcdi_mon.h"
 
 #if EFSYS_OPT_MON_MCDI
 
@@ -314,9 +315,15 @@ efx_mcdi_read_sensors(
 	__in		uint32_t size)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_READ_SENSORS_EXT_IN_LEN,
-			    MC_CMD_READ_SENSORS_EXT_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_READ_SENSORS_EXT_IN_LEN,
+		MC_CMD_READ_SENSORS_EXT_OUT_LEN);
 	uint32_t addr_lo, addr_hi;
+	efx_rc_t rc;
+
+	if (EFSYS_MEM_SIZE(esmp) < size) {
+		rc = EINVAL;
+		goto fail1;
+	}
 
 	req.emr_cmd = MC_CMD_READ_SENSORS;
 	req.emr_in_buf = payload;
@@ -334,6 +341,11 @@ efx_mcdi_read_sensors(
 	efx_mcdi_execute(enp, &req);
 
 	return (req.emr_rc);
+
+fail1:
+	EFSYS_PROBE1(fail1, efx_rc_t, rc);
+
+	return (rc);
 }
 
 static	__checkReturn	efx_rc_t
@@ -342,8 +354,8 @@ efx_mcdi_sensor_info_npages(
 	__out		uint32_t *npagesp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SENSOR_INFO_EXT_IN_LEN,
-			    MC_CMD_SENSOR_INFO_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SENSOR_INFO_EXT_IN_LEN,
+		MC_CMD_SENSOR_INFO_OUT_LENMAX);
 	int page;
 	efx_rc_t rc;
 
@@ -386,8 +398,8 @@ efx_mcdi_sensor_info(
 	__in			size_t npages)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_SENSOR_INFO_EXT_IN_LEN,
-			    MC_CMD_SENSOR_INFO_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_SENSOR_INFO_EXT_IN_LEN,
+		MC_CMD_SENSOR_INFO_OUT_LENMAX);
 	uint32_t page;
 	efx_rc_t rc;
 
diff --git a/drivers/net/sfc/base/medford_nic.c b/drivers/net/sfc/base/medford_nic.c
index d361d654..9c6e8ea7 100644
--- a/drivers/net/sfc/base/medford_nic.c
+++ b/drivers/net/sfc/base/medford_nic.c
@@ -40,12 +40,11 @@ efx_mcdi_get_rxdp_config(
 	__out		uint32_t *end_paddingp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_RXDP_CONFIG_IN_LEN,
-			    MC_CMD_GET_RXDP_CONFIG_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_RXDP_CONFIG_IN_LEN,
+		MC_CMD_GET_RXDP_CONFIG_OUT_LEN);
 	uint32_t end_padding;
 	efx_rc_t rc;
 
-	memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_RXDP_CONFIG;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_RXDP_CONFIG_IN_LEN;
diff --git a/drivers/net/sfc/base/siena_mac.c b/drivers/net/sfc/base/siena_mac.c
index 29bbff8a..427fcde6 100644
--- a/drivers/net/sfc/base/siena_mac.c
+++ b/drivers/net/sfc/base/siena_mac.c
@@ -92,14 +92,13 @@ siena_mac_reconfigure(
 	efx_port_t *epp = &(enp->en_port);
 	efx_oword_t multicast_hash[2];
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MAX(MC_CMD_SET_MAC_IN_LEN,
-				MC_CMD_SET_MAC_OUT_LEN),
-			    MAX(MC_CMD_SET_MCAST_HASH_IN_LEN,
-				MC_CMD_SET_MCAST_HASH_OUT_LEN))];
+	EFX_MCDI_DECLARE_BUF(payload,
+		MAX(MC_CMD_SET_MAC_IN_LEN, MC_CMD_SET_MCAST_HASH_IN_LEN),
+		MAX(MC_CMD_SET_MAC_OUT_LEN, MC_CMD_SET_MCAST_HASH_OUT_LEN));
+
 	unsigned int fcntl;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_MAC;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_MAC_IN_LEN;
diff --git a/drivers/net/sfc/base/siena_nic.c b/drivers/net/sfc/base/siena_nic.c
index fcc8f151..09b67a77 100644
--- a/drivers/net/sfc/base/siena_nic.c
+++ b/drivers/net/sfc/base/siena_nic.c
@@ -42,11 +42,10 @@ siena_nic_get_partn_mask(
 	__out			unsigned int *maskp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_NVRAM_TYPES_IN_LEN,
-			    MC_CMD_NVRAM_TYPES_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_NVRAM_TYPES_IN_LEN,
+		MC_CMD_NVRAM_TYPES_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_NVRAM_TYPES;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_NVRAM_TYPES_IN_LEN;
diff --git a/drivers/net/sfc/base/siena_nvram.c b/drivers/net/sfc/base/siena_nvram.c
index af4cf172..7556df16 100644
--- a/drivers/net/sfc/base/siena_nvram.c
+++ b/drivers/net/sfc/base/siena_nvram.c
@@ -433,12 +433,11 @@ siena_nvram_get_subtype(
 	__out			uint32_t *subtypep)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_BOARD_CFG_IN_LEN,
-			    MC_CMD_GET_BOARD_CFG_OUT_LENMAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_BOARD_CFG_IN_LEN,
+		MC_CMD_GET_BOARD_CFG_OUT_LENMAX);
 	efx_word_t *fw_list;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_BOARD_CFG;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_BOARD_CFG_IN_LEN;
diff --git a/drivers/net/sfc/base/siena_phy.c b/drivers/net/sfc/base/siena_phy.c
index b90ccabc..7addad7d 100644
--- a/drivers/net/sfc/base/siena_phy.c
+++ b/drivers/net/sfc/base/siena_phy.c
@@ -193,11 +193,10 @@ siena_phy_get_link(
 	__out		siena_link_state_t *slsp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_LINK_IN_LEN,
-			    MC_CMD_GET_LINK_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_LINK_IN_LEN,
+		MC_CMD_GET_LINK_OUT_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_LINK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_LINK_IN_LEN;
@@ -268,16 +267,14 @@ siena_phy_reconfigure(
 {
 	efx_port_t *epp = &(enp->en_port);
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MAX(MC_CMD_SET_ID_LED_IN_LEN,
-				MC_CMD_SET_ID_LED_OUT_LEN),
-			    MAX(MC_CMD_SET_LINK_IN_LEN,
-				MC_CMD_SET_LINK_OUT_LEN))];
+	EFX_MCDI_DECLARE_BUF(payload,
+		MAX(MC_CMD_SET_ID_LED_IN_LEN, MC_CMD_SET_LINK_IN_LEN),
+		MAX(MC_CMD_SET_ID_LED_OUT_LEN, MC_CMD_SET_LINK_OUT_LEN));
 	uint32_t cap_mask;
 	unsigned int led_mode;
 	unsigned int speed;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_SET_LINK;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_SET_LINK_IN_LEN;
@@ -383,12 +380,11 @@ siena_phy_verify(
 	__in		efx_nic_t *enp)
 {
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_GET_PHY_STATE_IN_LEN,
-			    MC_CMD_GET_PHY_STATE_OUT_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_GET_PHY_STATE_IN_LEN,
+		MC_CMD_GET_PHY_STATE_OUT_LEN);
 	uint32_t state;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_GET_PHY_STATE;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_GET_PHY_STATE_IN_LEN;
@@ -552,11 +548,10 @@ siena_phy_stats_update(
 	uint32_t vmask = encp->enc_mcdi_phy_stat_mask;
 	uint64_t smask;
 	efx_mcdi_req_t req;
-	uint8_t payload[MAX(MC_CMD_PHY_STATS_IN_LEN,
-			    MC_CMD_PHY_STATS_OUT_DMA_LEN)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_PHY_STATS_IN_LEN,
+		MC_CMD_PHY_STATS_OUT_DMA_LEN);
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_PHY_STATS;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_PHY_STATS_IN_LEN;
@@ -641,14 +636,13 @@ siena_phy_bist_poll(
 	__in			size_t count)
 {
 	efx_nic_cfg_t *encp = &(enp->en_nic_cfg);
-	uint8_t payload[MAX(MC_CMD_POLL_BIST_IN_LEN,
-			    MCDI_CTL_SDU_LEN_MAX)];
+	EFX_MCDI_DECLARE_BUF(payload, MC_CMD_POLL_BIST_IN_LEN,
+		MCDI_CTL_SDU_LEN_MAX);
 	uint32_t value_mask = 0;
 	efx_mcdi_req_t req;
 	uint32_t result;
 	efx_rc_t rc;
 
-	(void) memset(payload, 0, sizeof (payload));
 	req.emr_cmd = MC_CMD_POLL_BIST;
 	req.emr_in_buf = payload;
 	req.emr_in_length = MC_CMD_POLL_BIST_IN_LEN;
diff --git a/drivers/net/sfc/sfc_ef10_rx.c b/drivers/net/sfc/sfc_ef10_rx.c
index bd2cbd09..7069c534 100644
--- a/drivers/net/sfc/sfc_ef10_rx.c
+++ b/drivers/net/sfc/sfc_ef10_rx.c
@@ -489,11 +489,11 @@ sfc_ef10_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	uint16_t n_rx_pkts;
 	efx_qword_t rx_ev;
 
+	n_rx_pkts = sfc_ef10_rx_prepared(rxq, rx_pkts, nb_pkts);
+
 	if (unlikely(rxq->flags &
 		     (SFC_EF10_RXQ_NOT_RUNNING | SFC_EF10_RXQ_EXCEPTION)))
-		return 0;
-
-	n_rx_pkts = sfc_ef10_rx_prepared(rxq, rx_pkts, nb_pkts);
+		goto done;
 
 	evq_old_read_ptr = rxq->evq_read_ptr;
 	while (n_rx_pkts != nb_pkts && sfc_ef10_rx_get_event(rxq, &rx_ev)) {
@@ -513,6 +513,7 @@ sfc_ef10_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts)
 	/* It is not a problem if we refill in the case of exception */
 	sfc_ef10_rx_qrefill(rxq);
 
+done:
 	return n_rx_pkts;
 }
 
@@ -646,8 +647,9 @@ sfc_ef10_rx_qstart(struct sfc_dp_rxq *dp_rxq, unsigned int evq_read_ptr)
 {
 	struct sfc_ef10_rxq *rxq = sfc_ef10_rxq_by_dp_rxq(dp_rxq);
 
-	rxq->prepared = 0;
-	rxq->completed = rxq->added = 0;
+	SFC_ASSERT(rxq->prepared == 0);
+	SFC_ASSERT(rxq->completed == 0);
+	SFC_ASSERT(rxq->added == 0);
 
 	sfc_ef10_rx_qrefill(rxq);
 
@@ -694,12 +696,16 @@ sfc_ef10_rx_qpurge(struct sfc_dp_rxq *dp_rxq)
 	unsigned int i;
 	struct sfc_ef10_rx_sw_desc *rxd;
 
+	rxq->prepared = 0;
+
 	for (i = rxq->completed; i != rxq->added; ++i) {
 		rxd = &rxq->sw_ring[i & rxq->ptr_mask];
 		rte_mempool_put(rxq->refill_mb_pool, rxd->mbuf);
 		rxd->mbuf = NULL;
 	}
 
+	rxq->completed = rxq->added = 0;
+
 	rxq->flags &= ~SFC_EF10_RXQ_STARTED;
 }
 
diff --git a/drivers/net/sfc/sfc_ethdev.c b/drivers/net/sfc/sfc_ethdev.c
index 1b160b5e..005df401 100644
--- a/drivers/net/sfc/sfc_ethdev.c
+++ b/drivers/net/sfc/sfc_ethdev.c
@@ -35,6 +35,7 @@
 #include <rte_pci.h>
 #include <rte_bus_pci.h>
 #include <rte_errno.h>
+#include <rte_string_fns.h>
 
 #include "efx.h"
 
@@ -458,8 +459,6 @@ sfc_rx_queue_release(void *queue)
 
 	sfc_log_init(sa, "RxQ=%u", sw_index);
 
-	sa->eth_dev->data->rx_queues[sw_index] = NULL;
-
 	sfc_rx_qfini(sa, sw_index);
 
 	sfc_adapter_unlock(sa);
@@ -514,9 +513,6 @@ sfc_tx_queue_release(void *queue)
 
 	sfc_adapter_lock(sa);
 
-	SFC_ASSERT(sw_index < sa->eth_dev->data->nb_tx_queues);
-	sa->eth_dev->data->tx_queues[sw_index] = NULL;
-
 	sfc_tx_qfini(sa, sw_index);
 
 	sfc_adapter_unlock(sa);
@@ -666,7 +662,7 @@ sfc_xstats_get_names(struct rte_eth_dev *dev,
 	for (i = 0; i < EFX_MAC_NSTATS; ++i) {
 		if (EFX_MAC_STAT_SUPPORTED(port->mac_stats_mask, i)) {
 			if (xstats_names != NULL && nstats < xstats_count)
-				strncpy(xstats_names[nstats].name,
+				strlcpy(xstats_names[nstats].name,
 					efx_mac_stat_name(sa->nic, i),
 					sizeof(xstats_names[0].name));
 			nstats++;
@@ -744,9 +740,8 @@ sfc_xstats_get_names_by_id(struct rte_eth_dev *dev,
 		if ((ids == NULL) || (ids[nb_written] == nb_supported)) {
 			char *name = xstats_names[nb_written++].name;
 
-			strncpy(name, efx_mac_stat_name(sa->nic, i),
+			strlcpy(name, efx_mac_stat_name(sa->nic, i),
 				sizeof(xstats_names[0].name));
-			name[sizeof(xstats_names[0].name) - 1] = '\0';
 		}
 
 		++nb_supported;
@@ -1230,14 +1225,10 @@ sfc_dev_rss_hash_conf_get(struct rte_eth_dev *dev,
 			  struct rte_eth_rss_conf *rss_conf)
 {
 	struct sfc_adapter *sa = dev->data->dev_private;
-	struct sfc_port *port = &sa->port;
 
-	if ((sa->rss_support != EFX_RX_SCALE_EXCLUSIVE) || port->isolated)
+	if (sa->rss_support != EFX_RX_SCALE_EXCLUSIVE)
 		return -ENOTSUP;
 
-	if (sa->rss_channels == 0)
-		return -EINVAL;
-
 	sfc_adapter_lock(sa);
 
 	/*
diff --git a/drivers/net/sfc/sfc_rx.c b/drivers/net/sfc/sfc_rx.c
index 8fc93d68..238aa5ea 100644
--- a/drivers/net/sfc/sfc_rx.c
+++ b/drivers/net/sfc/sfc_rx.c
@@ -1028,6 +1028,7 @@ sfc_rx_qfini(struct sfc_adapter *sa, unsigned int sw_index)
 	struct sfc_rxq *rxq;
 
 	SFC_ASSERT(sw_index < sa->rxq_count);
+	sa->eth_dev->data->rx_queues[sw_index] = NULL;
 
 	rxq_info = &sa->rxq_info[sw_index];
 
@@ -1340,7 +1341,7 @@ sfc_rx_configure(struct sfc_adapter *sa)
 		goto fail_check_mode;
 
 	if (nb_rx_queues == sa->rxq_count)
-		goto done;
+		goto configure_rss;
 
 	if (sa->rxq_info == NULL) {
 		rc = ENOMEM;
@@ -1377,6 +1378,7 @@ sfc_rx_configure(struct sfc_adapter *sa)
 		sa->rxq_count++;
 	}
 
+configure_rss:
 #if EFSYS_OPT_RX_SCALE
 	sa->rss_channels = (dev_conf->rxmode.mq_mode == ETH_MQ_RX_RSS) ?
 			   MIN(sa->rxq_count, EFX_MAXRSS) : 0;
@@ -1395,7 +1397,6 @@ sfc_rx_configure(struct sfc_adapter *sa)
 	}
 #endif
 
-done:
 	return 0;
 
 fail_rx_process_adv_conf_rss:
diff --git a/drivers/net/sfc/sfc_tx.c b/drivers/net/sfc/sfc_tx.c
index d1320f46..9b1e6541 100644
--- a/drivers/net/sfc/sfc_tx.c
+++ b/drivers/net/sfc/sfc_tx.c
@@ -239,6 +239,8 @@ sfc_tx_qfini(struct sfc_adapter *sa, unsigned int sw_index)
 	sfc_log_init(sa, "TxQ = %u", sw_index);
 
 	SFC_ASSERT(sw_index < sa->txq_count);
+	sa->eth_dev->data->tx_queues[sw_index] = NULL;
+
 	txq_info = &sa->txq_info[sw_index];
 
 	txq = txq_info->txq;