Merge branch 'net-smcv2.1-ISM-device-support'

Wen Gu says:

====================
net/smc: implement SMCv2.1 virtual ISM device support

The fourth edition of SMCv2 adds the SMC version 2.1 feature updates for
SMC-Dv2 with virtual ISM. Virtual ISM are created and supported mainly by
OS or hypervisor software, comparable to IBM ISM which is based on platform
firmware or hardware.

With the introduction of virtual ISM, SMCv2.1 makes some updates:

- Introduce feature bitmask to indicate supplemental features.
- Reserve a range of CHIDs for virtual ISM.
- Support extended GIDs (128 bits) in CLC handshake.

So this patch set aims to implement these updates in Linux kernel. And it
acts as the first part of SMC-D virtual ISM extension & loopback-ism [1].

[1] https://lore.kernel.org/netdev/1695568613-125057-1-git-send-email-guwen@linux.alibaba.com/

v8->v7:
- Patch #7: v7 mistakenly changed the type of gid_ext in
  smc_clc_msg_accept_confirm to u64 instead of __be64 as previous versions
  when fixing the rebase conflicts. So fix this mistake.

v7->v6:
Link: https://lore.kernel.org/netdev/20231219084536.8158-1-guwen@linux.alibaba.com/
- Collect the Reviewed-by tag in v6;
- Patch #3: redefine the struct smc_clc_msg_accept_confirm;
- Patch #7: Because that the Patch #3 already adds '__packed' to
  smc_clc_msg_accept_confirm, so Patch #7 doesn't need to do the same thing.
  But this is a minor change, so I kept the 'Reviewed-by' tag.

Other changes in previous versions but not yet acked:
- Patch #1: Some minor changes in subject and fix the format issue
  (length exceeds 80 columns) compared to v3.
- Patch #5: removes useless ini->feature_mask assignment in __smc_connect()
  and smc_listen_v2_check() compared to v4.
- Patch #8: new added, compared to v3.

v6->v5:
Link: https://lore.kernel.org/netdev/1702371151-125258-1-git-send-email-guwen@linux.alibaba.com/
- Add 'Reviewed-by' label given in the previous versions:
  * Patch #4, #6, #9, #10 have nothing changed since v3;
- Patch #2:
  * fix the format issue (Alignment should match open parenthesis) compared to v5;
  * remove useless clc->hdr.length assignment in smcr_clc_prep_confirm_accept()
    compared to v5;
- Patch #3: new added compared to v5.
- Patch #7: some minor changes like aclc_v2->aclc or clc_v2->clc compared to v5
  due to the introduction of Patch #3. Since there were no major changes, I kept
  the 'Reviewed-by' label.

Other changes in previous versions but not yet acked:
- Patch #1: Some minor changes in subject and fix the format issue
  (length exceeds 80 columns) compared to v3.
- Patch #5: removes useless ini->feature_mask assignment in __smc_connect()
  and smc_listen_v2_check() compared to v4.
- Patch #8: new added, compared to v3.

v5->v4:
Link: https://lore.kernel.org/netdev/1702021259-41504-1-git-send-email-guwen@linux.alibaba.com/
- Patch #6: improve the comment of SMCD_CLC_MAX_V2_GID_ENTRIES;
- Patch #4: remove useless ini->feature_mask assignment;

v4->v3:
https://lore.kernel.org/netdev/1701920994-73705-1-git-send-email-guwen@linux.alibaba.com/
- Patch #6: use SMCD_CLC_MAX_V2_GID_ENTRIES to indicate the max gid
  entries in CLC proposal and using SMC_MAX_V2_ISM_DEVS to indicate the
  max devices to propose;
- Patch #6: use i and i+1 in smc_find_ism_v2_device_serv();
- Patch #2: replace the large if-else block in smc_clc_send_confirm_accept()
  with 2 subfunctions;
- Fix missing byte order conversion of GID and token in CLC handshake,
  which is in a separate patch sending to net:
  https://lore.kernel.org/netdev/1701882157-87956-1-git-send-email-guwen@linux.alibaba.com/
- Patch #7: add extended GID in SMC-D lgr netlink attribute;

v3->v2:
https://lore.kernel.org/netdev/1701343695-122657-1-git-send-email-guwen@linux.alibaba.com/
- Rename smc_clc_fill_fce as smc_clc_fill_fce_v2x;
- Remove ISM_IDENT_MASK from drivers/s390/net/ism.h;
- Add explicitly assigning 'false' to ism_v2_capable in ism_dev_init();
- Remove smc_ism_set_v2_capable() helper for now, and introduce it in
  later loopback-ism implementation;

v2->v1:
- Fix sparse complaint;
- Rebase to the latest net-next;
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

10 files changed, 417 insertions, 241 deletions

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 7fc2f3c6d248..a2cb30af46cb 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -677,8 +677,6 @@ static bool smc_isascii(char *hostname)
 static void smc_conn_save_peer_info_fce(struct smc_sock *smc,
 					struct smc_clc_msg_accept_confirm *clc)
 {
-	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
-		(struct smc_clc_msg_accept_confirm_v2 *)clc;
 	struct smc_clc_first_contact_ext *fce;
 	int clc_v2_len;
 
@@ -687,17 +685,15 @@ static void smc_conn_save_peer_info_fce(struct smc_sock *smc,
 		return;
 
 	if (smc->conn.lgr->is_smcd) {
-		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->d1.eid,
+		memcpy(smc->conn.lgr->negotiated_eid, clc->d1.eid,
 		       SMC_MAX_EID_LEN);
-		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm_v2,
-					 d1);
+		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm, d1);
 	} else {
-		memcpy(smc->conn.lgr->negotiated_eid, clc_v2->r1.eid,
+		memcpy(smc->conn.lgr->negotiated_eid, clc->r1.eid,
 		       SMC_MAX_EID_LEN);
-		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm_v2,
-					 r1);
+		clc_v2_len = offsetofend(struct smc_clc_msg_accept_confirm, r1);
 	}
-	fce = (struct smc_clc_first_contact_ext *)(((u8 *)clc_v2) + clc_v2_len);
+	fce = (struct smc_clc_first_contact_ext *)(((u8 *)clc) + clc_v2_len);
 	smc->conn.lgr->peer_os = fce->os_type;
 	smc->conn.lgr->peer_smc_release = fce->release;
 	if (smc_isascii(fce->hostname))
@@ -1048,7 +1044,8 @@ static int smc_find_ism_v2_device_clnt(struct smc_sock *smc,
 {
 	int rc = SMC_CLC_DECL_NOSMCDDEV;
 	struct smcd_dev *smcd;
-	int i = 1;
+	int i = 1, entry = 1;
+	bool is_virtual;
 	u16 chid;
 
 	if (smcd_indicated(ini->smc_type_v1))
@@ -1060,14 +1057,23 @@ static int smc_find_ism_v2_device_clnt(struct smc_sock *smc,
 		chid = smc_ism_get_chid(smcd);
 		if (!smc_find_ism_v2_is_unique_chid(chid, ini, i))
 			continue;
+		is_virtual = __smc_ism_is_virtual(chid);
 		if (!smc_pnet_is_pnetid_set(smcd->pnetid) ||
 		    smc_pnet_is_ndev_pnetid(sock_net(&smc->sk), smcd->pnetid)) {
+			if (is_virtual && entry == SMCD_CLC_MAX_V2_GID_ENTRIES)
+				/* It's the last GID-CHID entry left in CLC
+				 * Proposal SMC-Dv2 extension, but a virtual
+				 * ISM device will take two entries. So give
+				 * up it and try the next potential ISM device.
+				 */
+				continue;
 			ini->ism_dev[i] = smcd;
 			ini->ism_chid[i] = chid;
 			ini->is_smcd = true;
 			rc = 0;
 			i++;
-			if (i > SMC_MAX_ISM_DEVS)
+			entry = is_virtual ? entry + 2 : entry + 1;
+			if (entry > SMCD_CLC_MAX_V2_GID_ENTRIES)
 				break;
 		}
 	}
@@ -1149,13 +1155,13 @@ static int smc_connect_ism_vlan_cleanup(struct smc_sock *smc,
 }
 
 #define SMC_CLC_MAX_ACCEPT_LEN \
-	(sizeof(struct smc_clc_msg_accept_confirm_v2) + \
+	(sizeof(struct smc_clc_msg_accept_confirm) + \
 	 sizeof(struct smc_clc_first_contact_ext_v2x) + \
 	 sizeof(struct smc_clc_msg_trail))
 
 /* CLC handshake during connect */
 static int smc_connect_clc(struct smc_sock *smc,
-			   struct smc_clc_msg_accept_confirm_v2 *aclc2,
+			   struct smc_clc_msg_accept_confirm *aclc,
 			   struct smc_init_info *ini)
 {
 	int rc = 0;
@@ -1165,7 +1171,7 @@ static int smc_connect_clc(struct smc_sock *smc,
 	if (rc)
 		return rc;
 	/* receive SMC Accept CLC message */
-	return smc_clc_wait_msg(smc, aclc2, SMC_CLC_MAX_ACCEPT_LEN,
+	return smc_clc_wait_msg(smc, aclc, SMC_CLC_MAX_ACCEPT_LEN,
 				SMC_CLC_ACCEPT, CLC_WAIT_TIME);
 }
 
@@ -1201,10 +1207,8 @@ static int smc_connect_rdma_v2_prepare(struct smc_sock *smc,
 				       struct smc_clc_msg_accept_confirm *aclc,
 				       struct smc_init_info *ini)
 {
-	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
-		(struct smc_clc_msg_accept_confirm_v2 *)aclc;
 	struct smc_clc_first_contact_ext *fce =
-		smc_get_clc_first_contact_ext(clc_v2, false);
+		smc_get_clc_first_contact_ext(aclc, false);
 	struct net *net = sock_net(&smc->sk);
 	int rc;
 
@@ -1327,10 +1331,7 @@ static int smc_connect_rdma(struct smc_sock *smc,
 	}
 
 	if (aclc->hdr.version > SMC_V1) {
-		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
-			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
-
-		eid = clc_v2->r1.eid;
+		eid = aclc->r1.eid;
 		if (ini->first_contact_local)
 			smc_fill_gid_list(link->lgr, &ini->smcrv2.gidlist,
 					  link->smcibdev, link->gid);
@@ -1371,7 +1372,7 @@ connect_abort:
  * Determine from the CHID of the received CLC ACCEPT the ISM device chosen.
  */
 static int
-smc_v2_determine_accepted_chid(struct smc_clc_msg_accept_confirm_v2 *aclc,
+smc_v2_determine_accepted_chid(struct smc_clc_msg_accept_confirm *aclc,
 			       struct smc_init_info *ini)
 {
 	int i;
@@ -1398,12 +1399,9 @@ static int smc_connect_ism(struct smc_sock *smc,
 	ini->first_contact_peer = aclc->hdr.typev2 & SMC_FIRST_CONTACT_MASK;
 
 	if (aclc->hdr.version == SMC_V2) {
-		struct smc_clc_msg_accept_confirm_v2 *aclc_v2 =
-			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
-
 		if (ini->first_contact_peer) {
 			struct smc_clc_first_contact_ext *fce =
-				smc_get_clc_first_contact_ext(aclc_v2, true);
+				smc_get_clc_first_contact_ext(aclc, true);
 
 			ini->release_nr = fce->release;
 			rc = smc_clc_clnt_v2x_features_validate(fce, ini);
@@ -1411,11 +1409,16 @@ static int smc_connect_ism(struct smc_sock *smc,
 				return rc;
 		}
 
-		rc = smc_v2_determine_accepted_chid(aclc_v2, ini);
+		rc = smc_v2_determine_accepted_chid(aclc, ini);
 		if (rc)
 			return rc;
+
+		if (__smc_ism_is_virtual(ini->ism_chid[ini->ism_selected]))
+			ini->ism_peer_gid[ini->ism_selected].gid_ext =
+						ntohll(aclc->d1.gid_ext);
+		/* for non-virtual ISM devices, peer gid_ext remains 0. */
 	}
-	ini->ism_peer_gid[ini->ism_selected] = ntohll(aclc->d0.gid);
+	ini->ism_peer_gid[ini->ism_selected].gid = ntohll(aclc->d0.gid);
 
 	/* there is only one lgr role for SMC-D; use server lock */
 	mutex_lock(&smc_server_lgr_pending);
@@ -1437,12 +1440,8 @@ static int smc_connect_ism(struct smc_sock *smc,
 	smc_rx_init(smc);
 	smc_tx_init(smc);
 
-	if (aclc->hdr.version > SMC_V1) {
-		struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
-			(struct smc_clc_msg_accept_confirm_v2 *)aclc;
-
-		eid = clc_v2->d1.eid;
-	}
+	if (aclc->hdr.version > SMC_V1)
+		eid = aclc->d1.eid;
 
 	rc = smc_clc_send_confirm(smc, ini->first_contact_local,
 				  aclc->hdr.version, eid, ini);
@@ -1493,7 +1492,6 @@ static int smc_connect_check_aclc(struct smc_init_info *ini,
 static int __smc_connect(struct smc_sock *smc)
 {
 	u8 version = smc_ism_is_v2_capable() ? SMC_V2 : SMC_V1;
-	struct smc_clc_msg_accept_confirm_v2 *aclc2;
 	struct smc_clc_msg_accept_confirm *aclc;
 	struct smc_init_info *ini = NULL;
 	u8 *buf = NULL;
@@ -1541,11 +1539,10 @@ static int __smc_connect(struct smc_sock *smc)
 		rc = SMC_CLC_DECL_MEM;
 		goto fallback;
 	}
-	aclc2 = (struct smc_clc_msg_accept_confirm_v2 *)buf;
-	aclc = (struct smc_clc_msg_accept_confirm *)aclc2;
+	aclc = (struct smc_clc_msg_accept_confirm *)buf;
 
 	/* perform CLC handshake */
-	rc = smc_connect_clc(smc, aclc2, ini);
+	rc = smc_connect_clc(smc, aclc, ini);
 	if (rc) {
 		/* -EAGAIN on timeout, see tcp_recvmsg() */
 		if (rc == -EAGAIN) {
@@ -2106,7 +2103,8 @@ static bool smc_is_already_selected(struct smcd_dev *smcd,
 
 /* check for ISM devices matching proposed ISM devices */
 static void smc_check_ism_v2_match(struct smc_init_info *ini,
-				   u16 proposed_chid, u64 proposed_gid,
+				   u16 proposed_chid,
+				   struct smcd_gid *proposed_gid,
 				   unsigned int *matches)
 {
 	struct smcd_dev *smcd;
@@ -2118,7 +2116,11 @@ static void smc_check_ism_v2_match(struct smc_init_info *ini,
 			continue;
 		if (smc_ism_get_chid(smcd) == proposed_chid &&
 		    !smc_ism_cantalk(proposed_gid, ISM_RESERVED_VLANID, smcd)) {
-			ini->ism_peer_gid[*matches] = proposed_gid;
+			ini->ism_peer_gid[*matches].gid = proposed_gid->gid;
+			if (__smc_ism_is_virtual(proposed_chid))
+				ini->ism_peer_gid[*matches].gid_ext =
+							proposed_gid->gid_ext;
+				/* non-virtual ISM's peer gid_ext remains 0. */
 			ini->ism_dev[*matches] = smcd;
 			(*matches)++;
 			break;
@@ -2140,9 +2142,11 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc,
 	struct smc_clc_v2_extension *smc_v2_ext;
 	struct smc_clc_msg_smcd *pclc_smcd;
 	unsigned int matches = 0;
+	struct smcd_gid smcd_gid;
 	u8 smcd_version;
 	u8 *eid = NULL;
 	int i, rc;
+	u16 chid;
 
 	if (!(ini->smcd_version & SMC_V2) || !smcd_indicated(ini->smc_type_v2))
 		goto not_found;
@@ -2152,18 +2156,35 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc,
 	smcd_v2_ext = smc_get_clc_smcd_v2_ext(smc_v2_ext);
 
 	mutex_lock(&smcd_dev_list.mutex);
-	if (pclc_smcd->ism.chid)
+	if (pclc_smcd->ism.chid) {
 		/* check for ISM device matching proposed native ISM device */
+		smcd_gid.gid = ntohll(pclc_smcd->ism.gid);
+		smcd_gid.gid_ext = 0;
 		smc_check_ism_v2_match(ini, ntohs(pclc_smcd->ism.chid),
-				       ntohll(pclc_smcd->ism.gid), &matches);
-	for (i = 1; i <= smc_v2_ext->hdr.ism_gid_cnt; i++) {
+				       &smcd_gid, &matches);
+	}
+	for (i = 0; i < smc_v2_ext->hdr.ism_gid_cnt; i++) {
 		/* check for ISM devices matching proposed non-native ISM
 		 * devices
 		 */
-		smc_check_ism_v2_match(ini,
-				       ntohs(smcd_v2_ext->gidchid[i - 1].chid),
-				       ntohll(smcd_v2_ext->gidchid[i - 1].gid),
-				       &matches);
+		smcd_gid.gid = ntohll(smcd_v2_ext->gidchid[i].gid);
+		smcd_gid.gid_ext = 0;
+		chid = ntohs(smcd_v2_ext->gidchid[i].chid);
+		if (__smc_ism_is_virtual(chid)) {
+			if ((i + 1) == smc_v2_ext->hdr.ism_gid_cnt ||
+			    chid != ntohs(smcd_v2_ext->gidchid[i + 1].chid))
+				/* each virtual ISM device takes two GID-CHID
+				 * entries and CHID of the second entry repeats
+				 * that of the first entry.
+				 *
+				 * So check if the next GID-CHID entry exists
+				 * and both two entries' CHIDs are the same.
+				 */
+				continue;
+			smcd_gid.gid_ext =
+				ntohll(smcd_v2_ext->gidchid[++i].gid);
+		}
+		smc_check_ism_v2_match(ini, chid, &smcd_gid, &matches);
 	}
 	mutex_unlock(&smcd_dev_list.mutex);
 
@@ -2212,7 +2233,8 @@ static void smc_find_ism_v1_device_serv(struct smc_sock *new_smc,
 	if (!(ini->smcd_version & SMC_V1) || !smcd_indicated(ini->smc_type_v1))
 		goto not_found;
 	ini->is_smcd = true; /* prepare ISM check */
-	ini->ism_peer_gid[0] = ntohll(pclc_smcd->ism.gid);
+	ini->ism_peer_gid[0].gid = ntohll(pclc_smcd->ism.gid);
+	ini->ism_peer_gid[0].gid_ext = 0;
 	rc = smc_find_ism_device(new_smc, ini);
 	if (rc)
 		goto not_found;
diff --git a/net/smc/smc.h b/net/smc/smc.h
index cd51261b7d9e..df64efd2dee8 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -29,9 +29,6 @@
 #define SMCPROTO_SMC		0	/* SMC protocol, IPv4 */
 #define SMCPROTO_SMC6		1	/* SMC protocol, IPv6 */
 
-#define SMC_MAX_ISM_DEVS	8	/* max # of proposed non-native ISM
-					 * devices
-					 */
 #define SMC_AUTOCORKING_DEFAULT_SIZE	0x10000	/* 64K by default */
 
 extern struct proto smc_proto;
@@ -58,6 +55,13 @@ enum smc_state {		/* possible states of an SMC socket */
 	SMC_PROCESSABORT	= 27,
 };
 
+enum smc_supplemental_features {
+	SMC_SPF_VIRT_ISM_DEV	= 0,
+};
+
+#define SMC_FEATURE_MASK \
+	(BIT(SMC_SPF_VIRT_ISM_DEV))
+
 struct smc_link_group;
 
 struct smc_wr_rx_hdr {	/* common prefix part of LLC and CDC to demultiplex */
diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 95e19aa3e769..9a13709bea1c 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -155,10 +155,12 @@ static int smc_clc_ueid_remove(char *ueid)
 			rc = 0;
 		}
 	}
+#if IS_ENABLED(CONFIG_S390)
 	if (!rc && !smc_clc_eid_table.ueid_cnt) {
 		smc_clc_eid_table.seid_enabled = 1;
 		rc = -EAGAIN;	/* indicate success and enabling of seid */
 	}
+#endif
 	write_unlock(&smc_clc_eid_table.lock);
 	return rc;
 }
@@ -273,22 +275,30 @@ err:
 
 int smc_nl_enable_seid(struct sk_buff *skb, struct genl_info *info)
 {
+#if IS_ENABLED(CONFIG_S390)
 	write_lock(&smc_clc_eid_table.lock);
 	smc_clc_eid_table.seid_enabled = 1;
 	write_unlock(&smc_clc_eid_table.lock);
 	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
 }
 
 int smc_nl_disable_seid(struct sk_buff *skb, struct genl_info *info)
 {
 	int rc = 0;
 
+#if IS_ENABLED(CONFIG_S390)
 	write_lock(&smc_clc_eid_table.lock);
 	if (!smc_clc_eid_table.ueid_cnt)
 		rc = -ENOENT;
 	else
 		smc_clc_eid_table.seid_enabled = 0;
 	write_unlock(&smc_clc_eid_table.lock);
+#else
+	rc = -EOPNOTSUPP;
+#endif
 	return rc;
 }
 
@@ -377,9 +387,9 @@ static bool smc_clc_msg_prop_valid(struct smc_clc_msg_proposal *pclc)
 
 /* check arriving CLC accept or confirm */
 static bool
-smc_clc_msg_acc_conf_valid(struct smc_clc_msg_accept_confirm_v2 *clc_v2)
+smc_clc_msg_acc_conf_valid(struct smc_clc_msg_accept_confirm *clc)
 {
-	struct smc_clc_msg_hdr *hdr = &clc_v2->hdr;
+	struct smc_clc_msg_hdr *hdr = &clc->hdr;
 
 	if (hdr->typev1 != SMC_TYPE_R && hdr->typev1 != SMC_TYPE_D)
 		return false;
@@ -418,15 +428,16 @@ smc_clc_msg_decl_valid(struct smc_clc_msg_decline *dclc)
 	return true;
 }
 
-static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
-			    struct smc_init_info *ini)
+static int smc_clc_fill_fce_v2x(struct smc_clc_first_contact_ext_v2x *fce_v2x,
+				struct smc_init_info *ini)
 {
-	int ret = sizeof(*fce);
+	int ret = sizeof(*fce_v2x);
 
-	memset(fce, 0, sizeof(*fce));
-	fce->fce_v2_base.os_type = SMC_CLC_OS_LINUX;
-	fce->fce_v2_base.release = ini->release_nr;
-	memcpy(fce->fce_v2_base.hostname, smc_hostname, sizeof(smc_hostname));
+	memset(fce_v2x, 0, sizeof(*fce_v2x));
+	fce_v2x->fce_v2_base.os_type = SMC_CLC_OS_LINUX;
+	fce_v2x->fce_v2_base.release = ini->release_nr;
+	memcpy(fce_v2x->fce_v2_base.hostname,
+	       smc_hostname, sizeof(smc_hostname));
 	if (ini->is_smcd && ini->release_nr < SMC_RELEASE_1) {
 		ret = sizeof(struct smc_clc_first_contact_ext);
 		goto out;
@@ -434,9 +445,10 @@ static int smc_clc_fill_fce(struct smc_clc_first_contact_ext_v2x *fce,
 
 	if (ini->release_nr >= SMC_RELEASE_1) {
 		if (!ini->is_smcd) {
-			fce->max_conns = ini->max_conns;
-			fce->max_links = ini->max_links;
+			fce_v2x->max_conns = ini->max_conns;
+			fce_v2x->max_links = ini->max_links;
 		}
+		fce_v2x->feature_mask = htons(ini->feature_mask);
 	}
 
 out:
@@ -448,7 +460,7 @@ out:
  */
 static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl)
 {
-	struct smc_clc_msg_accept_confirm_v2 *clc_v2;
+	struct smc_clc_msg_accept_confirm *clc;
 	struct smc_clc_msg_proposal *pclc;
 	struct smc_clc_msg_decline *dclc;
 	struct smc_clc_msg_trail *trl;
@@ -466,12 +478,11 @@ static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl)
 		break;
 	case SMC_CLC_ACCEPT:
 	case SMC_CLC_CONFIRM:
-		clc_v2 = (struct smc_clc_msg_accept_confirm_v2 *)clcm;
-		if (!smc_clc_msg_acc_conf_valid(clc_v2))
+		clc = (struct smc_clc_msg_accept_confirm *)clcm;
+		if (!smc_clc_msg_acc_conf_valid(clc))
 			return false;
 		trl = (struct smc_clc_msg_trail *)
-			((u8 *)clc_v2 + ntohs(clc_v2->hdr.length) -
-							sizeof(*trl));
+			((u8 *)clc + ntohs(clc->hdr.length) - sizeof(*trl));
 		break;
 	case SMC_CLC_DECLINE:
 		dclc = (struct smc_clc_msg_decline *)clcm;
@@ -882,11 +893,13 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 		       ETH_ALEN);
 	}
 	if (smcd_indicated(ini->smc_type_v1)) {
+		struct smcd_gid smcd_gid;
+
 		/* add SMC-D specifics */
 		if (ini->ism_dev[0]) {
 			smcd = ini->ism_dev[0];
-			pclc_smcd->ism.gid =
-				htonll(smcd->ops->get_local_gid(smcd));
+			smcd->ops->get_local_gid(smcd, &smcd_gid);
+			pclc_smcd->ism.gid = htonll(smcd_gid.gid);
 			pclc_smcd->ism.chid =
 				htons(smc_ism_get_chid(ini->ism_dev[0]));
 		}
@@ -907,6 +920,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 		pclc_smcd->v2_ext_offset = htons(v2_ext_offset);
 		plen += sizeof(*v2_ext);
 
+		v2_ext->feature_mask = htons(SMC_FEATURE_MASK);
 		read_lock(&smc_clc_eid_table.lock);
 		v2_ext->hdr.eid_cnt = smc_clc_eid_table.ueid_cnt;
 		plen += smc_clc_eid_table.ueid_cnt * SMC_MAX_EID_LEN;
@@ -918,10 +932,11 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 		read_unlock(&smc_clc_eid_table.lock);
 	}
 	if (smcd_indicated(ini->smc_type_v2)) {
+		struct smcd_gid smcd_gid;
 		u8 *eid = NULL;
+		int entry = 0;
 
 		v2_ext->hdr.flag.seid = smc_clc_eid_table.seid_enabled;
-		v2_ext->hdr.ism_gid_cnt = ini->ism_offered_cnt;
 		v2_ext->hdr.smcd_v2_ext_offset = htons(sizeof(*v2_ext) -
 				offsetofend(struct smc_clnt_opts_area_hdr,
 					    smcd_v2_ext_offset) +
@@ -933,14 +948,26 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 		if (ini->ism_offered_cnt) {
 			for (i = 1; i <= ini->ism_offered_cnt; i++) {
 				smcd = ini->ism_dev[i];
-				gidchids[i - 1].gid =
-					htonll(smcd->ops->get_local_gid(smcd));
-				gidchids[i - 1].chid =
+				smcd->ops->get_local_gid(smcd, &smcd_gid);
+				gidchids[entry].chid =
 					htons(smc_ism_get_chid(ini->ism_dev[i]));
+				gidchids[entry].gid = htonll(smcd_gid.gid);
+				if (smc_ism_is_virtual(smcd)) {
+					/* a virtual ISM device takes two
+					 * entries. CHID of the second entry
+					 * repeats that of the first entry.
+					 */
+					gidchids[entry + 1].chid =
+						gidchids[entry].chid;
+					gidchids[entry + 1].gid =
+						htonll(smcd_gid.gid_ext);
+					entry++;
+				}
+				entry++;
 			}
-			plen += ini->ism_offered_cnt *
-				sizeof(struct smc_clc_smcd_gid_chid);
+			plen += entry * sizeof(struct smc_clc_smcd_gid_chid);
 		}
+		v2_ext->hdr.ism_gid_cnt = entry;
 	}
 	if (smcr_indicated(ini->smc_type_v2)) {
 		memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
@@ -976,7 +1003,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 			vec[i++].iov_len = sizeof(*smcd_v2_ext);
 			if (ini->ism_offered_cnt) {
 				vec[i].iov_base = gidchids;
-				vec[i++].iov_len = ini->ism_offered_cnt *
+				vec[i++].iov_len = v2_ext->hdr.ism_gid_cnt *
 					sizeof(struct smc_clc_smcd_gid_chid);
 			}
 		}
@@ -997,109 +1024,143 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 	return reason_code;
 }
 
+static void
+smcd_clc_prep_confirm_accept(struct smc_connection *conn,
+			     struct smc_clc_msg_accept_confirm *clc,
+			     int first_contact, u8 version,
+			     u8 *eid, struct smc_init_info *ini,
+			     int *fce_len,
+			     struct smc_clc_first_contact_ext_v2x *fce_v2x,
+			     struct smc_clc_msg_trail *trl)
+{
+	struct smcd_dev *smcd = conn->lgr->smcd;
+	struct smcd_gid smcd_gid;
+	u16 chid;
+	int len;
+
+	/* SMC-D specific settings */
+	memcpy(clc->hdr.eyecatcher, SMCD_EYECATCHER,
+	       sizeof(SMCD_EYECATCHER));
+	smcd->ops->get_local_gid(smcd, &smcd_gid);
+	clc->hdr.typev1 = SMC_TYPE_D;
+	clc->d0.gid = htonll(smcd_gid.gid);
+	clc->d0.token = htonll(conn->rmb_desc->token);
+	clc->d0.dmbe_size = conn->rmbe_size_comp;
+	clc->d0.dmbe_idx = 0;
+	memcpy(&clc->d0.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
+	if (version == SMC_V1) {
+		clc->hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
+	} else {
+		chid = smc_ism_get_chid(smcd);
+		clc->d1.chid = htons(chid);
+		if (eid && eid[0])
+			memcpy(clc->d1.eid, eid, SMC_MAX_EID_LEN);
+		if (__smc_ism_is_virtual(chid))
+			clc->d1.gid_ext = htonll(smcd_gid.gid_ext);
+		len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2;
+		if (first_contact) {
+			*fce_len = smc_clc_fill_fce_v2x(fce_v2x, ini);
+			len += *fce_len;
+		}
+		clc->hdr.length = htons(len);
+	}
+	memcpy(trl->eyecatcher, SMCD_EYECATCHER,
+	       sizeof(SMCD_EYECATCHER));
+}
+
+static void
+smcr_clc_prep_confirm_accept(struct smc_connection *conn,
+			     struct smc_clc_msg_accept_confirm *clc,
+			     int first_contact, u8 version,
+			     u8 *eid, struct smc_init_info *ini,
+			     int *fce_len,
+			     struct smc_clc_first_contact_ext_v2x *fce_v2x,
+			     struct smc_clc_fce_gid_ext *gle,
+			     struct smc_clc_msg_trail *trl)
+{
+	struct smc_link *link = conn->lnk;
+	int len;
+
+	/* SMC-R specific settings */
+	memcpy(clc->hdr.eyecatcher, SMC_EYECATCHER,
+	       sizeof(SMC_EYECATCHER));
+	clc->hdr.typev1 = SMC_TYPE_R;
+	memcpy(clc->r0.lcl.id_for_peer, local_systemid,
+	       sizeof(local_systemid));
+	memcpy(&clc->r0.lcl.gid, link->gid, SMC_GID_SIZE);
+	memcpy(&clc->r0.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
+	       ETH_ALEN);
+	hton24(clc->r0.qpn, link->roce_qp->qp_num);
+	clc->r0.rmb_rkey =
+		htonl(conn->rmb_desc->mr[link->link_idx]->rkey);
+	clc->r0.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
+	clc->r0.rmbe_alert_token = htonl(conn->alert_token_local);
+	switch (clc->hdr.type) {
+	case SMC_CLC_ACCEPT:
+		clc->r0.qp_mtu = link->path_mtu;
+		break;
+	case SMC_CLC_CONFIRM:
+		clc->r0.qp_mtu = min(link->path_mtu, link->peer_mtu);
+		break;
+	}
+	clc->r0.rmbe_size = conn->rmbe_size_comp;
+	clc->r0.rmb_dma_addr = conn->rmb_desc->is_vm ?
+		cpu_to_be64((uintptr_t)conn->rmb_desc->cpu_addr) :
+		cpu_to_be64((u64)sg_dma_address
+			    (conn->rmb_desc->sgt[link->link_idx].sgl));
+	hton24(clc->r0.psn, link->psn_initial);
+	if (version == SMC_V1) {
+		clc->hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
+	} else {
+		if (eid && eid[0])
+			memcpy(clc->r1.eid, eid, SMC_MAX_EID_LEN);
+		len = SMCR_CLC_ACCEPT_CONFIRM_LEN_V2;
+		if (first_contact) {
+			*fce_len = smc_clc_fill_fce_v2x(fce_v2x, ini);
+			len += *fce_len;
+			fce_v2x->fce_v2_base.v2_direct =
+				!link->lgr->uses_gateway;
+			if (clc->hdr.type == SMC_CLC_CONFIRM) {
+				memset(gle, 0, sizeof(*gle));
+				gle->gid_cnt = ini->smcrv2.gidlist.len;
+				len += sizeof(*gle);
+				len += gle->gid_cnt * sizeof(gle->gid[0]);
+			}
+		}
+		clc->hdr.length = htons(len);
+	}
+	memcpy(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+}
+
 /* build and send CLC CONFIRM / ACCEPT message */
 static int smc_clc_send_confirm_accept(struct smc_sock *smc,
-				       struct smc_clc_msg_accept_confirm_v2 *clc_v2,
+				       struct smc_clc_msg_accept_confirm *clc,
 				       int first_contact, u8 version,
 				       u8 *eid, struct smc_init_info *ini)
 {
+	struct smc_clc_first_contact_ext_v2x fce_v2x;
 	struct smc_connection *conn = &smc->conn;
-	struct smc_clc_first_contact_ext_v2x fce;
-	struct smcd_dev *smcd = conn->lgr->smcd;
-	struct smc_clc_msg_accept_confirm *clc;
 	struct smc_clc_fce_gid_ext gle;
 	struct smc_clc_msg_trail trl;
-	int i, len, fce_len;
+	int i, fce_len;
 	struct kvec vec[5];
 	struct msghdr msg;
 
 	/* send SMC Confirm CLC msg */
-	clc = (struct smc_clc_msg_accept_confirm *)clc_v2;
 	clc->hdr.version = version;	/* SMC version */
 	if (first_contact)
 		clc->hdr.typev2 |= SMC_FIRST_CONTACT_MASK;
-	if (conn->lgr->is_smcd) {
-		/* SMC-D specific settings */
-		memcpy(clc->hdr.eyecatcher, SMCD_EYECATCHER,
-		       sizeof(SMCD_EYECATCHER));
-		clc->hdr.typev1 = SMC_TYPE_D;
-		clc->d0.gid = htonll(smcd->ops->get_local_gid(smcd));
-		clc->d0.token = htonll(conn->rmb_desc->token);
-		clc->d0.dmbe_size = conn->rmbe_size_comp;
-		clc->d0.dmbe_idx = 0;
-		memcpy(&clc->d0.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
-		if (version == SMC_V1) {
-			clc->hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
-		} else {
-			clc_v2->d1.chid = htons(smc_ism_get_chid(smcd));
-			if (eid && eid[0])
-				memcpy(clc_v2->d1.eid, eid, SMC_MAX_EID_LEN);
-			len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2;
-			if (first_contact) {
-				fce_len = smc_clc_fill_fce(&fce, ini);
-				len += fce_len;
-			}
-			clc_v2->hdr.length = htons(len);
-		}
-		memcpy(trl.eyecatcher, SMCD_EYECATCHER,
-		       sizeof(SMCD_EYECATCHER));
-	} else {
-		struct smc_link *link = conn->lnk;
-
-		/* SMC-R specific settings */
-		memcpy(clc->hdr.eyecatcher, SMC_EYECATCHER,
-		       sizeof(SMC_EYECATCHER));
-		clc->hdr.typev1 = SMC_TYPE_R;
-		clc->hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
-		memcpy(clc->r0.lcl.id_for_peer, local_systemid,
-		       sizeof(local_systemid));
-		memcpy(&clc->r0.lcl.gid, link->gid, SMC_GID_SIZE);
-		memcpy(&clc->r0.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
-		       ETH_ALEN);
-		hton24(clc->r0.qpn, link->roce_qp->qp_num);
-		clc->r0.rmb_rkey =
-			htonl(conn->rmb_desc->mr[link->link_idx]->rkey);
-		clc->r0.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
-		clc->r0.rmbe_alert_token = htonl(conn->alert_token_local);
-		switch (clc->hdr.type) {
-		case SMC_CLC_ACCEPT:
-			clc->r0.qp_mtu = link->path_mtu;
-			break;
-		case SMC_CLC_CONFIRM:
-			clc->r0.qp_mtu = min(link->path_mtu, link->peer_mtu);
-			break;
-		}
-		clc->r0.rmbe_size = conn->rmbe_size_comp;
-		clc->r0.rmb_dma_addr = conn->rmb_desc->is_vm ?
-			cpu_to_be64((uintptr_t)conn->rmb_desc->cpu_addr) :
-			cpu_to_be64((u64)sg_dma_address
-				    (conn->rmb_desc->sgt[link->link_idx].sgl));
-		hton24(clc->r0.psn, link->psn_initial);
-		if (version == SMC_V1) {
-			clc->hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
-		} else {
-			if (eid && eid[0])
-				memcpy(clc_v2->r1.eid, eid, SMC_MAX_EID_LEN);
-			len = SMCR_CLC_ACCEPT_CONFIRM_LEN_V2;
-			if (first_contact) {
-				fce_len = smc_clc_fill_fce(&fce, ini);
-				len += fce_len;
-				fce.fce_v2_base.v2_direct = !link->lgr->uses_gateway;
-				if (clc->hdr.type == SMC_CLC_CONFIRM) {
-					memset(&gle, 0, sizeof(gle));
-					gle.gid_cnt = ini->smcrv2.gidlist.len;
-					len += sizeof(gle);
-					len += gle.gid_cnt * sizeof(gle.gid[0]);
-				}
-			}
-			clc_v2->hdr.length = htons(len);
-		}
-		memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
-	}
-
+	if (conn->lgr->is_smcd)
+		smcd_clc_prep_confirm_accept(conn, clc, first_contact,
+					     version, eid, ini, &fce_len,
+					     &fce_v2x, &trl);
+	else
+		smcr_clc_prep_confirm_accept(conn, clc, first_contact,
+					     version, eid, ini, &fce_len,
+					     &fce_v2x, &gle, &trl);
 	memset(&msg, 0, sizeof(msg));
 	i = 0;
-	vec[i].iov_base = clc_v2;
+	vec[i].iov_base = clc;
 	if (version > SMC_V1)
 		vec[i++].iov_len = (clc->hdr.typev1 == SMC_TYPE_D ?
 					SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 :
@@ -1111,7 +1172,7 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 						SMCR_CLC_ACCEPT_CONFIRM_LEN) -
 				   sizeof(trl);
 	if (version > SMC_V1 && first_contact) {
-		vec[i].iov_base = &fce;
+		vec[i].iov_base = &fce_v2x;
 		vec[i++].iov_len = fce_len;
 		if (!conn->lgr->is_smcd) {
 			if (clc->hdr.type == SMC_CLC_CONFIRM) {
@@ -1133,16 +1194,16 @@ static int smc_clc_send_confirm_accept(struct smc_sock *smc,
 int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
 			 u8 version, u8 *eid, struct smc_init_info *ini)
 {
-	struct smc_clc_msg_accept_confirm_v2 cclc_v2;
+	struct smc_clc_msg_accept_confirm cclc;
 	int reason_code = 0;
 	int len;
 
 	/* send SMC Confirm CLC msg */
-	memset(&cclc_v2, 0, sizeof(cclc_v2));
-	cclc_v2.hdr.type = SMC_CLC_CONFIRM;
-	len = smc_clc_send_confirm_accept(smc, &cclc_v2, clnt_first_contact,
+	memset(&cclc, 0, sizeof(cclc));
+	cclc.hdr.type = SMC_CLC_CONFIRM;
+	len = smc_clc_send_confirm_accept(smc, &cclc, clnt_first_contact,
 					  version, eid, ini);
-	if (len < ntohs(cclc_v2.hdr.length)) {
+	if (len < ntohs(cclc.hdr.length)) {
 		if (len >= 0) {
 			reason_code = -ENETUNREACH;
 			smc->sk.sk_err = -reason_code;
@@ -1158,14 +1219,14 @@ int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
 int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
 			u8 version, u8 *negotiated_eid, struct smc_init_info *ini)
 {
-	struct smc_clc_msg_accept_confirm_v2 aclc_v2;
+	struct smc_clc_msg_accept_confirm aclc;
 	int len;
 
-	memset(&aclc_v2, 0, sizeof(aclc_v2));
-	aclc_v2.hdr.type = SMC_CLC_ACCEPT;
-	len = smc_clc_send_confirm_accept(new_smc, &aclc_v2, srv_first_contact,
+	memset(&aclc, 0, sizeof(aclc));
+	aclc.hdr.type = SMC_CLC_ACCEPT;
+	len = smc_clc_send_confirm_accept(new_smc, &aclc, srv_first_contact,
 					  version, negotiated_eid, ini);
-	if (len < ntohs(aclc_v2.hdr.length))
+	if (len < ntohs(aclc.hdr.length))
 		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;
 
 	return len > 0 ? 0 : len;
@@ -1180,6 +1241,7 @@ int smc_clc_srv_v2x_features_validate(struct smc_sock *smc,
 
 	ini->max_conns = SMC_CONN_PER_LGR_MAX;
 	ini->max_links = SMC_LINKS_ADD_LNK_MAX;
+	ini->feature_mask = SMC_FEATURE_MASK;
 
 	if ((!(ini->smcd_version & SMC_V2) && !(ini->smcr_version & SMC_V2)) ||
 	    ini->release_nr < SMC_RELEASE_1)
@@ -1223,6 +1285,8 @@ int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
 			return SMC_CLC_DECL_MAXLINKERR;
 		ini->max_links = fce_v2x->max_links;
 	}
+	/* common supplemental features of server and client */
+	ini->feature_mask = ntohs(fce_v2x->feature_mask) & SMC_FEATURE_MASK;
 
 	return 0;
 }
@@ -1230,10 +1294,8 @@ int smc_clc_clnt_v2x_features_validate(struct smc_clc_first_contact_ext *fce,
 int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
 				       struct smc_init_info *ini)
 {
-	struct smc_clc_msg_accept_confirm_v2 *clc_v2 =
-		(struct smc_clc_msg_accept_confirm_v2 *)cclc;
 	struct smc_clc_first_contact_ext *fce =
-		smc_get_clc_first_contact_ext(clc_v2, ini->is_smcd);
+		smc_get_clc_first_contact_ext(cclc, ini->is_smcd);
 	struct smc_clc_first_contact_ext_v2x *fce_v2x =
 		(struct smc_clc_first_contact_ext_v2x *)fce;
 
@@ -1253,6 +1315,8 @@ int smc_clc_v2x_features_confirm_check(struct smc_clc_msg_accept_confirm *cclc,
 		if (fce_v2x->max_links != ini->max_links)
 			return SMC_CLC_DECL_MAXLINKERR;
 	}
+	/* common supplemental features returned by client */
+	ini->feature_mask = ntohs(fce_v2x->feature_mask);
 
 	return 0;
 }
@@ -1274,7 +1338,11 @@ void __init smc_clc_init(void)
 	INIT_LIST_HEAD(&smc_clc_eid_table.list);
 	rwlock_init(&smc_clc_eid_table.lock);
 	smc_clc_eid_table.ueid_cnt = 0;
+#if IS_ENABLED(CONFIG_S390)
 	smc_clc_eid_table.seid_enabled = 1;
+#else
+	smc_clc_eid_table.seid_enabled = 0;
+#endif
 }
 
 void smc_clc_exit(void)
diff --git a/net/smc/smc_clc.h b/net/smc/smc_clc.h
index 1697b84d85be..a9f9bdd26dcd 100644
--- a/net/smc/smc_clc.h
+++ b/net/smc/smc_clc.h
@@ -138,7 +138,8 @@ struct smc_clc_v2_extension {
 	u8 roce[16];		/* RoCEv2 GID */
 	u8 max_conns;
 	u8 max_links;
-	u8 reserved[14];
+	__be16 feature_mask;
+	u8 reserved[12];
 	u8 user_eids[][SMC_MAX_EID_LEN];
 };
 
@@ -171,6 +172,11 @@ struct smc_clc_msg_proposal {	/* clc proposal message sent by Linux */
 
 #define SMC_CLC_MAX_V6_PREFIX		8
 #define SMC_CLC_MAX_UEID		8
+#define SMCD_CLC_MAX_V2_GID_ENTRIES	8 /* max # of CHID-GID entries in CLC
+					   * proposal SMC-Dv2 extension.
+					   * each ISM device takes one entry and
+					   * each virtual ISM takes two entries.
+					   */
 
 struct smc_clc_msg_proposal_area {
 	struct smc_clc_msg_proposal		pclc_base;
@@ -180,7 +186,8 @@ struct smc_clc_msg_proposal_area {
 	struct smc_clc_v2_extension		pclc_v2_ext;
 	u8			user_eids[SMC_CLC_MAX_UEID][SMC_MAX_EID_LEN];
 	struct smc_clc_smcd_v2_extension	pclc_smcd_v2_ext;
-	struct smc_clc_smcd_gid_chid		pclc_gidchids[SMC_MAX_ISM_DEVS];
+	struct smc_clc_smcd_gid_chid
+				pclc_gidchids[SMCD_CLC_MAX_V2_GID_ENTRIES];
 	struct smc_clc_msg_trail		pclc_trl;
 };
 
@@ -240,9 +247,14 @@ struct smc_clc_first_contact_ext {
 
 struct smc_clc_first_contact_ext_v2x {
 	struct smc_clc_first_contact_ext fce_v2_base;
-	u8 max_conns; /* for SMC-R only */
-	u8 max_links; /* for SMC-R only */
-	u8 reserved3[2];
+	union {
+		struct {
+			u8 max_conns; /* for SMC-R only */
+			u8 max_links; /* for SMC-R only */
+		};
+		u8 reserved3[2];	/* for SMC-D only */
+	};
+	__be16 feature_mask;
 	__be32 vendor_exp_options;
 	u8 reserved4[8];
 } __packed;		/* format defined in
@@ -259,28 +271,21 @@ struct smc_clc_fce_gid_ext {
 struct smc_clc_msg_accept_confirm {	/* clc accept / confirm message */
 	struct smc_clc_msg_hdr hdr;
 	union {
-		struct smcr_clc_msg_accept_confirm r0; /* SMC-R */
-		struct { /* SMC-D */
-			struct smcd_clc_msg_accept_confirm_common d0;
-			u32 reserved5[3];
-		};
-	};
-} __packed;			/* format defined in RFC7609 */
-
-struct smc_clc_msg_accept_confirm_v2 {	/* clc accept / confirm message */
-	struct smc_clc_msg_hdr hdr;
-	union {
 		struct { /* SMC-R */
 			struct smcr_clc_msg_accept_confirm r0;
-			u8 eid[SMC_MAX_EID_LEN];
-			u8 reserved6[8];
-		} r1;
+			struct { /* v2 only */
+				u8 eid[SMC_MAX_EID_LEN];
+				u8 reserved6[8];
+			} __packed r1;
+		};
 		struct { /* SMC-D */
 			struct smcd_clc_msg_accept_confirm_common d0;
-			__be16 chid;
-			u8 eid[SMC_MAX_EID_LEN];
-			u8 reserved5[8];
-		} d1;
+			struct { /* v2 only, but 12 bytes reserved in v1 */
+				__be16 chid;
+				u8 eid[SMC_MAX_EID_LEN];
+				__be64 gid_ext;
+			} __packed d1;
+		};
 	};
 };
 
@@ -389,24 +394,23 @@ smc_get_clc_smcd_v2_ext(struct smc_clc_v2_extension *prop_v2ext)
 }
 
 static inline struct smc_clc_first_contact_ext *
-smc_get_clc_first_contact_ext(struct smc_clc_msg_accept_confirm_v2 *clc_v2,
+smc_get_clc_first_contact_ext(struct smc_clc_msg_accept_confirm *clc,
 			      bool is_smcd)
 {
 	int clc_v2_len;
 
-	if (clc_v2->hdr.version == SMC_V1 ||
-	    !(clc_v2->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
+	if (clc->hdr.version == SMC_V1 ||
+	    !(clc->hdr.typev2 & SMC_FIRST_CONTACT_MASK))
 		return NULL;
 
 	if (is_smcd)
 		clc_v2_len =
-			offsetofend(struct smc_clc_msg_accept_confirm_v2, d1);
+			offsetofend(struct smc_clc_msg_accept_confirm, d1);
 	else
 		clc_v2_len =
-			offsetofend(struct smc_clc_msg_accept_confirm_v2, r1);
+			offsetofend(struct smc_clc_msg_accept_confirm, r1);
 
-	return (struct smc_clc_first_contact_ext *)(((u8 *)clc_v2) +
-						    clc_v2_len);
+	return (struct smc_clc_first_contact_ext *)(((u8 *)clc) + clc_v2_len);
 }
 
 struct smcd_dev;
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index d520ee62c8ec..95cc95458e2d 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -506,6 +506,7 @@ static int smc_nl_fill_smcd_lgr(struct smc_link_group *lgr,
 {
 	char smc_pnet[SMC_MAX_PNETID_LEN + 1];
 	struct smcd_dev *smcd = lgr->smcd;
+	struct smcd_gid smcd_gid;
 	struct nlattr *attrs;
 	void *nlh;
 
@@ -521,13 +522,19 @@ static int smc_nl_fill_smcd_lgr(struct smc_link_group *lgr,
 
 	if (nla_put_u32(skb, SMC_NLA_LGR_D_ID, *((u32 *)&lgr->id)))
 		goto errattr;
+	smcd->ops->get_local_gid(smcd, &smcd_gid);
 	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_D_GID,
-			      smcd->ops->get_local_gid(smcd),
-				  SMC_NLA_LGR_D_PAD))
+			      smcd_gid.gid, SMC_NLA_LGR_D_PAD))
 		goto errattr;
-	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_D_PEER_GID, lgr->peer_gid,
+	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_D_EXT_GID,
+			      smcd_gid.gid_ext, SMC_NLA_LGR_D_PAD))
+		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_D_PEER_GID, lgr->peer_gid.gid,
 			      SMC_NLA_LGR_D_PAD))
 		goto errattr;
+	if (nla_put_u64_64bit(skb, SMC_NLA_LGR_D_PEER_EXT_GID,
+			      lgr->peer_gid.gid_ext, SMC_NLA_LGR_D_PAD))
+		goto errattr;
 	if (nla_put_u8(skb, SMC_NLA_LGR_D_VLAN_ID, lgr->vlan_id))
 		goto errattr;
 	if (nla_put_u32(skb, SMC_NLA_LGR_D_CONNS_NUM, lgr->conns_num))
@@ -876,7 +883,10 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
 		/* SMC-D specific settings */
 		smcd = ini->ism_dev[ini->ism_selected];
 		get_device(smcd->ops->get_dev(smcd));
-		lgr->peer_gid = ini->ism_peer_gid[ini->ism_selected];
+		lgr->peer_gid.gid =
+			ini->ism_peer_gid[ini->ism_selected].gid;
+		lgr->peer_gid.gid_ext =
+			ini->ism_peer_gid[ini->ism_selected].gid_ext;
 		lgr->smcd = ini->ism_dev[ini->ism_selected];
 		lgr_list = &ini->ism_dev[ini->ism_selected]->lgr_list;
 		lgr_lock = &lgr->smcd->lgr_lock;
@@ -1514,7 +1524,8 @@ void smc_lgr_terminate_sched(struct smc_link_group *lgr)
 }
 
 /* Called when peer lgr shutdown (regularly or abnormally) is received */
-void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
+void smc_smcd_terminate(struct smcd_dev *dev, struct smcd_gid *peer_gid,
+			unsigned short vlan)
 {
 	struct smc_link_group *lgr, *l;
 	LIST_HEAD(lgr_free_list);
@@ -1522,9 +1533,12 @@ void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
 	/* run common cleanup function and build free list */
 	spin_lock_bh(&dev->lgr_lock);
 	list_for_each_entry_safe(lgr, l, &dev->lgr_list, list) {
-		if ((!peer_gid || lgr->peer_gid == peer_gid) &&
+		if ((!peer_gid->gid ||
+		     (lgr->peer_gid.gid == peer_gid->gid &&
+		      !smc_ism_is_virtual(dev) ? 1 :
+		      lgr->peer_gid.gid_ext == peer_gid->gid_ext)) &&
 		    (vlan == VLAN_VID_MASK || lgr->vlan_id == vlan)) {
-			if (peer_gid) /* peer triggered termination */
+			if (peer_gid->gid) /* peer triggered termination */
 				lgr->peer_shutdown = 1;
 			list_move(&lgr->list, &lgr_free_list);
 			lgr->freeing = 1;
@@ -1860,9 +1874,12 @@ static bool smcr_lgr_match(struct smc_link_group *lgr, u8 smcr_version,
 }
 
 static bool smcd_lgr_match(struct smc_link_group *lgr,
-			   struct smcd_dev *smcismdev, u64 peer_gid)
+			   struct smcd_dev *smcismdev,
+			   struct smcd_gid *peer_gid)
 {
-	return lgr->peer_gid == peer_gid && lgr->smcd == smcismdev;
+	return lgr->peer_gid.gid == peer_gid->gid && lgr->smcd == smcismdev &&
+		smc_ism_is_virtual(smcismdev) ?
+		(lgr->peer_gid.gid_ext == peer_gid->gid_ext) : 1;
 }
 
 /* create a new SMC connection (and a new link group if necessary) */
@@ -1892,7 +1909,7 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
 		write_lock_bh(&lgr->conns_lock);
 		if ((ini->is_smcd ?
 		     smcd_lgr_match(lgr, ini->ism_dev[ini->ism_selected],
-				    ini->ism_peer_gid[ini->ism_selected]) :
+				    &ini->ism_peer_gid[ini->ism_selected]) :
 		     smcr_lgr_match(lgr, ini->smcr_version,
 				    ini->peer_systemid,
 				    ini->peer_gid, ini->peer_mac, role,
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 120027d40469..1f175376037b 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -17,9 +17,11 @@
 #include <linux/pci.h>
 #include <rdma/ib_verbs.h>
 #include <net/genetlink.h>
+#include <net/smc.h>
 
 #include "smc.h"
 #include "smc_ib.h"
+#include "smc_clc.h"
 
 #define SMC_RMBS_PER_LGR_MAX	255	/* max. # of RMBs per link group */
 #define SMC_CONN_PER_LGR_MIN	16	/* min. # of connections per link group */
@@ -355,7 +357,7 @@ struct smc_link_group {
 						/* max links can be added in lgr */
 		};
 		struct { /* SMC-D */
-			u64			peer_gid;
+			struct smcd_gid		peer_gid;
 						/* Peer GID (remote) */
 			struct smcd_dev		*smcd;
 						/* ISM device for VLAN reg. */
@@ -392,6 +394,11 @@ struct smc_init_info_smcrv2 {
 	struct smc_gidlist	gidlist;
 };
 
+#define SMC_MAX_V2_ISM_DEVS	SMCD_CLC_MAX_V2_GID_ENTRIES
+				/* max # of proposed non-native ISM devices,
+				 * which can't exceed the max # of CHID-GID
+				 * entries in CLC proposal SMC-Dv2 extension.
+				 */
 struct smc_init_info {
 	u8			is_smcd;
 	u8			smc_type_v1;
@@ -401,6 +408,7 @@ struct smc_init_info {
 	u8			max_links;
 	u8			first_contact_peer;
 	u8			first_contact_local;
+	u16			feature_mask;
 	unsigned short		vlan_id;
 	u32			rc;
 	u8			negotiated_eid[SMC_MAX_EID_LEN];
@@ -416,9 +424,9 @@ struct smc_init_info {
 	u32			ib_clcqpn;
 	struct smc_init_info_smcrv2 smcrv2;
 	/* SMC-D */
-	u64			ism_peer_gid[SMC_MAX_ISM_DEVS + 1];
-	struct smcd_dev		*ism_dev[SMC_MAX_ISM_DEVS + 1];
-	u16			ism_chid[SMC_MAX_ISM_DEVS + 1];
+	struct smcd_gid		ism_peer_gid[SMC_MAX_V2_ISM_DEVS + 1];
+	struct smcd_dev		*ism_dev[SMC_MAX_V2_ISM_DEVS + 1];
+	u16			ism_chid[SMC_MAX_V2_ISM_DEVS + 1];
 	u8			ism_offered_cnt; /* # of ISM devices offered */
 	u8			ism_selected;    /* index of selected ISM dev*/
 	u8			smcd_version;
@@ -544,7 +552,7 @@ void smc_lgr_hold(struct smc_link_group *lgr);
 void smc_lgr_put(struct smc_link_group *lgr);
 void smcr_port_add(struct smc_ib_device *smcibdev, u8 ibport);
 void smcr_port_err(struct smc_ib_device *smcibdev, u8 ibport);
-void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid,
+void smc_smcd_terminate(struct smcd_dev *dev, struct smcd_gid *peer_gid,
 			unsigned short vlan);
 void smc_smcd_terminate_all(struct smcd_dev *dev);
 void smc_smcr_terminate_all(struct smc_ib_device *smcibdev);
diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index a584613aca12..3fbe14e09ad8 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -21,6 +21,7 @@
 
 #include "smc.h"
 #include "smc_core.h"
+#include "smc_ism.h"
 
 struct smc_diag_dump_ctx {
 	int pos[2];
@@ -168,12 +169,16 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb,
 		struct smc_connection *conn = &smc->conn;
 		struct smcd_diag_dmbinfo dinfo;
 		struct smcd_dev *smcd = conn->lgr->smcd;
+		struct smcd_gid smcd_gid;
 
 		memset(&dinfo, 0, sizeof(dinfo));
 
 		dinfo.linkid = *((u32 *)conn->lgr->id);
-		dinfo.peer_gid = conn->lgr->peer_gid;
-		dinfo.my_gid = smcd->ops->get_local_gid(smcd);
+		dinfo.peer_gid = conn->lgr->peer_gid.gid;
+		dinfo.peer_gid_ext = conn->lgr->peer_gid.gid_ext;
+		smcd->ops->get_local_gid(smcd, &smcd_gid);
+		dinfo.my_gid = smcd_gid.gid;
+		dinfo.my_gid_ext = smcd_gid.gid_ext;
 		dinfo.token = conn->rmb_desc->token;
 		dinfo.peer_token = conn->peer_token;
 
diff --git a/net/smc/smc_ism.c b/net/smc/smc_ism.c
index fbee2493091f..ac88de2a06a0 100644
--- a/net/smc/smc_ism.c
+++ b/net/smc/smc_ism.c
@@ -43,8 +43,30 @@ static struct ism_client smc_ism_client = {
 };
 #endif
 
+static void smc_ism_create_system_eid(void)
+{
+	struct smc_ism_seid *seid =
+		(struct smc_ism_seid *)smc_ism_v2_system_eid;
+#if IS_ENABLED(CONFIG_S390)
+	struct cpuid id;
+	u16 ident_tail;
+	char tmp[5];
+
+	memcpy(seid->seid_string, "IBM-SYSZ-ISMSEID00000000", 24);
+	get_cpu_id(&id);
+	ident_tail = (u16)(id.ident & SMC_ISM_IDENT_MASK);
+	snprintf(tmp, 5, "%04X", ident_tail);
+	memcpy(seid->serial_number, tmp, 4);
+	snprintf(tmp, 5, "%04X", id.machine);
+	memcpy(seid->type, tmp, 4);
+#else
+	memset(seid, 0, SMC_MAX_EID_LEN);
+#endif
+}
+
 /* Test if an ISM communication is possible - same CPC */
-int smc_ism_cantalk(u64 peer_gid, unsigned short vlan_id, struct smcd_dev *smcd)
+int smc_ism_cantalk(struct smcd_gid *peer_gid, unsigned short vlan_id,
+		    struct smcd_dev *smcd)
 {
 	return smcd->ops->query_remote_gid(smcd, peer_gid, vlan_id ? 1 : 0,
 					   vlan_id);
@@ -208,7 +230,7 @@ int smc_ism_register_dmb(struct smc_link_group *lgr, int dmb_len,
 	dmb.dmb_len = dmb_len;
 	dmb.sba_idx = dmb_desc->sba_idx;
 	dmb.vlan_id = lgr->vlan_id;
-	dmb.rgid = lgr->peer_gid;
+	dmb.rgid = lgr->peer_gid.gid;
 	rc = lgr->smcd->ops->register_dmb(lgr->smcd, &dmb, &smc_ism_client);
 	if (!rc) {
 		dmb_desc->sba_idx = dmb.sba_idx;
@@ -340,18 +362,20 @@ union smcd_sw_event_info {
 
 static void smcd_handle_sw_event(struct smc_ism_event_work *wrk)
 {
+	struct smcd_gid peer_gid = { .gid = wrk->event.tok,
+				     .gid_ext = 0 };
 	union smcd_sw_event_info ev_info;
 
 	ev_info.info = wrk->event.info;
 	switch (wrk->event.code) {
 	case ISM_EVENT_CODE_SHUTDOWN:	/* Peer shut down DMBs */
-		smc_smcd_terminate(wrk->smcd, wrk->event.tok, ev_info.vlan_id);
+		smc_smcd_terminate(wrk->smcd, &peer_gid, ev_info.vlan_id);
 		break;
 	case ISM_EVENT_CODE_TESTLINK:	/* Activity timer */
 		if (ev_info.code == ISM_EVENT_REQUEST) {
 			ev_info.code = ISM_EVENT_RESPONSE;
 			wrk->smcd->ops->signal_event(wrk->smcd,
-						     wrk->event.tok,
+						     &peer_gid,
 						     ISM_EVENT_REQUEST_IR,
 						     ISM_EVENT_CODE_TESTLINK,
 						     ev_info.info);
@@ -365,10 +389,12 @@ static void smc_ism_event_work(struct work_struct *work)
 {
 	struct smc_ism_event_work *wrk =
 		container_of(work, struct smc_ism_event_work, work);
+	struct smcd_gid smcd_gid = { .gid = wrk->event.tok,
+				     .gid_ext = 0 };
 
 	switch (wrk->event.type) {
 	case ISM_EVENT_GID:	/* GID event, token is peer GID */
-		smc_smcd_terminate(wrk->smcd, wrk->event.tok, VLAN_VID_MASK);
+		smc_smcd_terminate(wrk->smcd, &smcd_gid, VLAN_VID_MASK);
 		break;
 	case ISM_EVENT_DMB:
 		break;
@@ -426,14 +452,8 @@ static void smcd_register_dev(struct ism_dev *ism)
 
 	mutex_lock(&smcd_dev_list.mutex);
 	if (list_empty(&smcd_dev_list.list)) {
-		u8 *system_eid = NULL;
-
-		system_eid = smcd->ops->get_system_eid();
-		if (smcd->ops->supports_v2()) {
+		if (smcd->ops->supports_v2())
 			smc_ism_v2_capable = true;
-			memcpy(smc_ism_v2_system_eid, system_eid,
-			       SMC_MAX_EID_LEN);
-		}
 	}
 	/* sort list: devices without pnetid before devices with pnetid */
 	if (smcd->pnetid[0])
@@ -525,7 +545,7 @@ int smc_ism_signal_shutdown(struct smc_link_group *lgr)
 	memcpy(ev_info.uid, lgr->id, SMC_LGR_ID_SIZE);
 	ev_info.vlan_id = lgr->vlan_id;
 	ev_info.code = ISM_EVENT_REQUEST;
-	rc = lgr->smcd->ops->signal_event(lgr->smcd, lgr->peer_gid,
+	rc = lgr->smcd->ops->signal_event(lgr->smcd, &lgr->peer_gid,
 					  ISM_EVENT_REQUEST_IR,
 					  ISM_EVENT_CODE_SHUTDOWN,
 					  ev_info.info);
@@ -537,10 +557,10 @@ int smc_ism_init(void)
 {
 	int rc = 0;
 
-#if IS_ENABLED(CONFIG_ISM)
 	smc_ism_v2_capable = false;
-	memset(smc_ism_v2_system_eid, 0, SMC_MAX_EID_LEN);
+	smc_ism_create_system_eid();
 
+#if IS_ENABLED(CONFIG_ISM)
 	rc = ism_register_client(&smc_ism_client);
 #endif
 	return rc;
diff --git a/net/smc/smc_ism.h b/net/smc/smc_ism.h
index 832b2f42d79f..ffff40c30a06 100644
--- a/net/smc/smc_ism.h
+++ b/net/smc/smc_ism.h
@@ -15,6 +15,9 @@
 
 #include "smc.h"
 
+#define SMC_VIRTUAL_ISM_CHID_MASK	0xFF00
+#define SMC_ISM_IDENT_MASK		0x00FFFF
+
 struct smcd_dev_list {	/* List of SMCD devices */
 	struct list_head list;
 	struct mutex mutex;	/* Protects list of devices */
@@ -28,9 +31,16 @@ struct smc_ism_vlanid {			/* VLAN id set on ISM device */
 	refcount_t refcnt;		/* Reference count */
 };
 
+struct smc_ism_seid {
+	u8 seid_string[24];
+	u8 serial_number[4];
+	u8 type[4];
+};
+
 struct smcd_dev;
 
-int smc_ism_cantalk(u64 peer_gid, unsigned short vlan_id, struct smcd_dev *dev);
+int smc_ism_cantalk(struct smcd_gid *peer_gid, unsigned short vlan_id,
+		    struct smcd_dev *dev);
 void smc_ism_set_conn(struct smc_connection *conn);
 void smc_ism_unset_conn(struct smc_connection *conn);
 int smc_ism_get_vlan(struct smcd_dev *dev, unsigned short vlan_id);
@@ -56,4 +66,22 @@ static inline int smc_ism_write(struct smcd_dev *smcd, u64 dmb_tok,
 	return rc < 0 ? rc : 0;
 }
 
+static inline bool __smc_ism_is_virtual(u16 chid)
+{
+	/* CHIDs in range of 0xFF00 to 0xFFFF are reserved
+	 * for virtual ISM device.
+	 *
+	 * loopback-ism:	0xFFFF
+	 * virtio-ism:		0xFF00 ~ 0xFFFE
+	 */
+	return ((chid & 0xFF00) == 0xFF00);
+}
+
+static inline bool smc_ism_is_virtual(struct smcd_dev *smcd)
+{
+	u16 chid = smcd->ops->get_chid(smcd);
+
+	return __smc_ism_is_virtual(chid);
+}
+
 #endif
diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c
index 11775401df68..9f2c58c5a86b 100644
--- a/net/smc/smc_pnet.c
+++ b/net/smc/smc_pnet.c
@@ -1103,8 +1103,8 @@ static void smc_pnet_find_ism_by_pnetid(struct net_device *ndev,
 	list_for_each_entry(ismdev, &smcd_dev_list.list, list) {
 		if (smc_pnet_match(ismdev->pnetid, ndev_pnetid) &&
 		    !ismdev->going_away &&
-		    (!ini->ism_peer_gid[0] ||
-		     !smc_ism_cantalk(ini->ism_peer_gid[0], ini->vlan_id,
+		    (!ini->ism_peer_gid[0].gid ||
+		     !smc_ism_cantalk(&ini->ism_peer_gid[0], ini->vlan_id,
 				      ismdev))) {
 			ini->ism_dev[0] = ismdev;
 			break;