[dpdk-dev] [PATCH] net/cxgbevf: fix inter-vm traffic when physical link down

[Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>]

From: Shagun Agrawal <shaguna@chelsio.com>

Add force_link_up devargs to always force link as up for VFs.
This enables VFs on the same NIC to send traffic to each other
even when physical link is down.

Fixes: 011ebc236ddc ("net/cxgbe: add skeleton VF driver")

Signed-off-by: Shagun Agrawal <shaguna@chelsio.com>
Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
---
 doc/guides/nics/cxgbe.rst        |  6 ++++++
 drivers/net/cxgbe/cxgbe.h        |  4 ++++
 drivers/net/cxgbe/cxgbe_ethdev.c | 14 ++++++--------
 drivers/net/cxgbe/cxgbe_main.c   | 17 ++++++++++++++++-
 4 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/doc/guides/nics/cxgbe.rst b/doc/guides/nics/cxgbe.rst
index 38d434802..78e391473 100644
--- a/doc/guides/nics/cxgbe.rst
+++ b/doc/guides/nics/cxgbe.rst
@@ -143,6 +143,12 @@ be passed as part of EAL arguments. For example,
   enabled, the outer VLAN tag is preserved in Q-in-Q packets. Otherwise,
   the outer VLAN tag is stripped in Q-in-Q packets.
 
+- ``force_link_up`` (default **0**)
+
+  When set to 1, CXGBEVF PMD always forces link as up for all VFs on
+  underlying Chelsio NICs. This enables multiple VFs on the same NIC
+  to send traffic to each other even when the physical link is down.
+
 .. _driver-compilation:
 
 Driver compilation and testing
diff --git a/drivers/net/cxgbe/cxgbe.h b/drivers/net/cxgbe/cxgbe.h
index b1a4e08df..75e0b21a8 100644
--- a/drivers/net/cxgbe/cxgbe.h
+++ b/drivers/net/cxgbe/cxgbe.h
@@ -25,6 +25,9 @@
 			  ETH_RSS_NONFRAG_IPV6_TCP | \
 			  ETH_RSS_NONFRAG_IPV6_UDP)
 
+#define CXGBE_DEVARG_FORCE_LINK_UP "force_link_up"
+
+bool force_linkup(struct adapter *adap);
 int cxgbe_probe(struct adapter *adapter);
 int cxgbevf_probe(struct adapter *adapter);
 void cxgbe_get_speed_caps(struct port_info *pi, u32 *speed_caps);
@@ -45,5 +48,6 @@ int setup_rss(struct port_info *pi);
 void cxgbe_enable_rx_queues(struct port_info *pi);
 void print_port_info(struct adapter *adap);
 void print_adapter_info(struct adapter *adap);
+int cxgbe_get_devargs(struct rte_devargs *devargs, const char *key);
 
 #endif /* _CXGBE_H_ */
diff --git a/drivers/net/cxgbe/cxgbe_ethdev.c b/drivers/net/cxgbe/cxgbe_ethdev.c
index 3ee7c44b1..2f1e4f691 100644
--- a/drivers/net/cxgbe/cxgbe_ethdev.c
+++ b/drivers/net/cxgbe/cxgbe_ethdev.c
@@ -204,19 +204,17 @@ int cxgbe_dev_link_update(struct rte_eth_dev *eth_dev,
 	struct port_info *pi = (struct port_info *)(eth_dev->data->dev_private);
 	struct adapter *adapter = pi->adapter;
 	struct sge *s = &adapter->sge;
-	struct rte_eth_link *old_link = &eth_dev->data->dev_link;
+	struct rte_eth_link new_link;
 	unsigned int work_done, budget = 4;
 
 	cxgbe_poll(&s->fw_evtq, NULL, budget, &work_done);
-	if (old_link->link_status == pi->link_cfg.link_ok)
-		return -1;  /* link not changed */
 
-	eth_dev->data->dev_link.link_status = pi->link_cfg.link_ok;
-	eth_dev->data->dev_link.link_duplex = ETH_LINK_FULL_DUPLEX;
-	eth_dev->data->dev_link.link_speed = pi->link_cfg.speed;
+	new_link.link_status = force_linkup(adapter) ?
+			       ETH_LINK_UP : pi->link_cfg.link_ok;
+	new_link.link_duplex = ETH_LINK_FULL_DUPLEX;
+	new_link.link_speed = pi->link_cfg.speed;
 
-	/* link has changed */
-	return 0;
+	return rte_eth_linkstatus_set(eth_dev, &new_link);
 }
 
 int cxgbe_dev_mtu_set(struct rte_eth_dev *eth_dev, uint16_t mtu)
diff --git a/drivers/net/cxgbe/cxgbe_main.c b/drivers/net/cxgbe/cxgbe_main.c
index 9ad5e5493..eed0f4e5c 100644
--- a/drivers/net/cxgbe/cxgbe_main.c
+++ b/drivers/net/cxgbe/cxgbe_main.c
@@ -404,7 +404,7 @@ check_devargs_handler(__rte_unused const char *key, const char *value,
 	return 0;
 }
 
-static int cxgbe_get_devargs(struct rte_devargs *devargs, const char *key)
+int cxgbe_get_devargs(struct rte_devargs *devargs, const char *key)
 {
 	struct rte_kvargs *kvlist;
 
@@ -942,6 +942,18 @@ void t4_os_portmod_changed(const struct adapter *adap, int port_id)
 			 pi->port_id, pi->mod_type);
 }
 
+inline bool force_linkup(struct adapter *adap)
+{
+	struct rte_pci_device *pdev = adap->pdev;
+
+	if (is_pf4(adap))
+		return false;	/* force_linkup not required for pf driver*/
+	if (!cxgbe_get_devargs(pdev->device.devargs,
+			       CXGBE_DEVARG_FORCE_LINK_UP))
+		return false;
+	return true;
+}
+
 /**
  * link_start - enable a port
  * @dev: the port to enable
@@ -987,6 +999,9 @@ int link_start(struct port_info *pi)
 		ret = t4_enable_vi_params(adapter, adapter->mbox, pi->viid,
 					  true, true, false);
 	}
+
+	if (ret == 0 && force_linkup(adapter))
+		pi->eth_dev->data->dev_link.link_status = ETH_LINK_UP;
 	return ret;
 }
 
-- 
2.14.1