[dpdk-dev] [PATCH v3 1/6] ethdev: add hairpin bind and unbind APIs

[Bing Zhao]

In single port hairpin mode, all the hairpin TX and RX queues belong
to the same device. After the queues are set up properly, there is
no other dependency between the TX queue and its RX peer queue. The
binding process that connected the TX and RX queues together from
hardware level will be done automatically during the device start
procedure. Everything required is configured and initialized already
for the binding process.

But in two ports hairpin mode, there will be some cross-dependences
between two different ports. Usually, the ports will be initialized
serially by the main thread but not in parallel. The earlier port
will not be able to enable the bind if the following peer port is
not yet configured with HW resources. What's more, if one port is
detached / attached dynamically, it would introduce more trouble
for the hairpin binding.

To overcome these, new APIs for binding and unbinding are added.
During startup, only the hairpin TX and RX peer queues will be set
up. Nothing will be done when starting the device if the queues are
without auto-bind attribute. Only after the required ports pair
started, the `rte_eth_hairpin_bind()` API can be called to bind the
all TX queues of the egress port to the RX queues of the peer port.
Then the connection between the egress and ingress ports pair will
be established.

The `rte_eth_hairpin_unbind()` API could be used to disconnect the
egress and the peer ingress ports. This should only be called before
the device is closed if needed. When doing the clean up, all the
egress and ingress pairs related to a single port should be taken
into consideration, especially in the hot unplug case.

Signed-off-by: Bing Zhao <bingz at nvidia.com>
Acked-by: Ori Kam <orika at nvidia.com>
---
v2: remove the all peer ports logic from rte API
---
 lib/librte_ethdev/rte_ethdev.c           | 46 ++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev.h           | 51 +++++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev_driver.h    | 52 ++++++++++++++++++++++++++++++++
 lib/librte_ethdev/rte_ethdev_version.map |  2 ++
 4 files changed, 151 insertions(+)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 0f56541..85a19bd 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -2162,6 +2162,52 @@ struct rte_eth_dev *
 	return eth_err(port_id, ret);
 }
 
+int
+rte_eth_hairpin_bind(uint16_t tx_port, uint16_t rx_port)
+{
+	struct rte_eth_dev *dev;
+	int ret;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(tx_port, -EINVAL);
+	dev = &rte_eth_devices[tx_port];
+	if (!dev->data->dev_started) {
+		RTE_ETHDEV_LOG(ERR, "TX port %d is not started", tx_port);
+		return -EBUSY;
+	}
+
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->hairpin_bind, -ENOTSUP);
+	ret = (*dev->dev_ops->hairpin_bind)(dev, rx_port);
+	if (ret)
+		RTE_ETHDEV_LOG(ERR, "Failed to bind hairpin TX %d "
+			       "to RX %d (%d - all ports)", tx_port,
+			       rx_port, RTE_MAX_ETHPORTS);
+
+	return ret;
+}
+
+int
+rte_eth_hairpin_unbind(uint16_t tx_port, uint16_t rx_port)
+{
+	struct rte_eth_dev *dev;
+	int ret;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(tx_port, -EINVAL);
+	dev = &rte_eth_devices[tx_port];
+	if (!dev->data->dev_started) {
+		RTE_ETHDEV_LOG(ERR, "TX port %d is already stopped", tx_port);
+		return -EBUSY;
+	}
+
+	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->hairpin_unbind, -ENOTSUP);
+	ret = (*dev->dev_ops->hairpin_unbind)(dev, rx_port);
+	if (ret)
+		RTE_ETHDEV_LOG(ERR, "Failed to unbind hairpin "
+			       "TX %d from RX %d (%d - all ports)", tx_port,
+			       rx_port, RTE_MAX_ETHPORTS);
+
+	return ret;
+}
+
 void
 rte_eth_tx_buffer_drop_callback(struct rte_mbuf **pkts, uint16_t unsent,
 		void *userdata __rte_unused)
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index d2bf74f..6206643 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -2128,6 +2128,57 @@ int rte_eth_tx_queue_setup(uint16_t port_id, uint16_t tx_queue_id,
 	 const struct rte_eth_hairpin_conf *conf);
 
 /**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Bind all hairpin TX queues of one port to the RX queues of the peer port.
+ * It is only allowed to call this API after all hairpin queues are configured
+ * properly and the devices of TX and peer RX are in started state.
+ *
+ * @param tx_port
+ *   The TX port identifier of the Ethernet device.
+ * @param rx_port
+ *   The peer RX port identifier of the Ethernet device.
+ *   RTE_MAX_ETHPORTS is allowed for the traversal of all devices.
+ *   RX port ID could have the same value with TX port ID.
+ *
+ * @return
+ *   - (0) if successful.
+ *   - (-EINVAL) if bad parameter.
+ *   - (-EBUSY) if device is not in started state.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ *   - Others detailed errors from PMD drivers.
+ */
+__rte_experimental
+int rte_eth_hairpin_bind(uint16_t tx_port, uint16_t rx_port);
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change, or be removed, without prior notice
+ *
+ * Unbind all hairpin TX queues of one port from the RX queues of the peer port.
+ * This should be called before closing the TX or RX devices (optional). After
+ * unbind the hairpin ports pair, it is allowed to bind them again.
+ * Changing queues configuration should be after stopping the device.
+ *
+ * @param tx_port
+ *   The TX port identifier of the Ethernet device.
+ * @param rx_port
+ *   The peer RX port identifier of the Ethernet device.
+ *   RTE_MAX_ETHPORTS is allowed for traversal of all devices.
+ *   RX port ID could have the same value with TX port ID.
+ *
+ * @return
+ *   - (0) if successful.
+ *   - (-EINVAL) if bad parameter.
+ *   - (-EBUSY) if device is in stopped state.
+ *   - (-ENOTSUP) if hardware doesn't support.
+ *   - Others detailed errors from PMD drivers.
+ */
+__rte_experimental
+int rte_eth_hairpin_unbind(uint16_t tx_port, uint16_t rx_port);
+
+/**
  * Return the NUMA socket to which an Ethernet device is connected
  *
  * @param port_id
diff --git a/lib/librte_ethdev/rte_ethdev_driver.h b/lib/librte_ethdev/rte_ethdev_driver.h
index c3062c2..f8eb879 100644
--- a/lib/librte_ethdev/rte_ethdev_driver.h
+++ b/lib/librte_ethdev/rte_ethdev_driver.h
@@ -575,6 +575,54 @@ typedef int (*eth_tx_hairpin_queue_setup_t)
 	 const struct rte_eth_hairpin_conf *hairpin_conf);
 
 /**
+ * @internal
+ * Bind all hairpin TX queues of one port to the RX queues of the peer port.
+ *
+ * @param dev
+ *   ethdev handle of port.
+ * @param rx_port
+ *   the peer RX port.
+ *
+ * @return
+ *   Negative errno value on error, 0 on success.
+ *
+ * @retval 0
+ *   Success, bind successfully.
+ * @retval -ENOTSUP
+ *   Bind API is not supported.
+ * @retval -EINVAL
+ *   One of the parameters is invalid.
+ * @retval -EBUSY
+ *   Device is not started.
+ */
+typedef int (*eth_hairpin_bind_t)(struct rte_eth_dev *dev,
+				uint16_t rx_port);
+
+/**
+ * @internal
+ * Unbind all hairpin TX queues of one port from the RX queues of the peer port.
+ *
+ * @param dev
+ *   ethdev handle of port.
+ * @param rx_port
+ *   the peer RX port.
+ *
+ * @return
+ *   Negative errno value on error, 0 on success.
+ *
+ * @retval 0
+ *   Success, bind successfully.
+ * @retval -ENOTSUP
+ *   Bind API is not supported.
+ * @retval -EINVAL
+ *   One of the parameters is invalid.
+ * @retval -EBUSY
+ *   Device is already stopped.
+ */
+typedef int (*eth_hairpin_unbind_t)(struct rte_eth_dev *dev,
+				  uint16_t rx_port);
+
+/**
  * @internal A structure containing the functions exported by an Ethernet driver.
  */
 struct eth_dev_ops {
@@ -713,6 +761,10 @@ struct eth_dev_ops {
 	/**< Set up device RX hairpin queue. */
 	eth_tx_hairpin_queue_setup_t tx_hairpin_queue_setup;
 	/**< Set up device TX hairpin queue. */
+	eth_hairpin_bind_t hairpin_bind;
+	/**< Bind all hairpin TX queues of device to the peer port RX queues. */
+	eth_hairpin_unbind_t hairpin_unbind;
+	/**< Unbind all hairpin TX queues from the peer port RX queues. */
 };
 
 /**
diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map
index c95ef51..18efe4e 100644
--- a/lib/librte_ethdev/rte_ethdev_version.map
+++ b/lib/librte_ethdev/rte_ethdev_version.map
@@ -227,6 +227,8 @@ EXPERIMENTAL {
 	rte_tm_wred_profile_delete;
 
 	# added in 20.11
+	rte_eth_hairpin_bind;
+	rte_eth_hairpin_unbind;
 	rte_eth_link_speed_to_str;
 	rte_eth_link_to_str;
 };
-- 
1.8.3.1