[PATCH v4 1/2] net/vhost: create datagram sockets immediately

[PATCH v4 1/2] net/vhost: create datagram sockets immediately

[Charles (Chas) Williams]

If you create a vhost server device, it doesn't create the actual datagram
socket until you call .dev_start().  If you call .dev_stop() is also
deletes those sockets.  For QEMU clients, this is a problem since QEMU
doesn't know how to re-attach to datagram sockets that have gone away.

To fix this, register and unregister the datagram sockets during device
creation and removal.

Fixes: ee584e9710b9 ("vhost: add driver on top of the library")

Signed-off-by: Chas Williams <ciwillia@brocade.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 45 +++++++++++++++------------------------
 1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index 60b0f51..c669e79 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -113,9 +113,6 @@ struct pmd_internal {
 	char *dev_name;
 	char *iface_name;
 	uint16_t max_queues;
-	uint64_t flags;
-
-	volatile uint16_t once;
 };
 
 struct internal_list {
@@ -772,35 +769,14 @@ vhost_driver_session_stop(void)
 }
 
 static int
-eth_dev_start(struct rte_eth_dev *dev)
+eth_dev_start(struct rte_eth_dev *dev __rte_unused)
 {
-	struct pmd_internal *internal = dev->data->dev_private;
-	int ret = 0;
-
-	if (rte_atomic16_cmpset(&internal->once, 0, 1)) {
-		ret = rte_vhost_driver_register(internal->iface_name,
-						internal->flags);
-		if (ret)
-			return ret;
-	}
-
-	/* We need only one message handling thread */
-	if (rte_atomic16_add_return(&nb_started_ports, 1) == 1)
-		ret = vhost_driver_session_start();
-
-	return ret;
+	return 0;
 }
 
 static void
-eth_dev_stop(struct rte_eth_dev *dev)
+eth_dev_stop(struct rte_eth_dev *dev __rte_unused)
 {
-	struct pmd_internal *internal = dev->data->dev_private;
-
-	if (rte_atomic16_cmpset(&internal->once, 1, 0))
-		rte_vhost_driver_unregister(internal->iface_name);
-
-	if (rte_atomic16_sub_return(&nb_started_ports, 1) == 0)
-		vhost_driver_session_stop();
 }
 
 static int
@@ -1043,7 +1019,6 @@ eth_dev_vhost_create(const char *name, char *iface_name, int16_t queues,
 	internal->iface_name = strdup(iface_name);
 	if (internal->iface_name == NULL)
 		goto error;
-	internal->flags = flags;
 
 	list->eth_dev = eth_dev;
 	pthread_mutex_lock(&internal_list_lock);
@@ -1078,6 +1053,15 @@ eth_dev_vhost_create(const char *name, char *iface_name, int16_t queues,
 	eth_dev->rx_pkt_burst = eth_vhost_rx;
 	eth_dev->tx_pkt_burst = eth_vhost_tx;
 
+	if (rte_vhost_driver_register(iface_name, flags))
+		goto error;
+
+	/* We need only one message handling thread */
+	if (rte_atomic16_add_return(&nb_started_ports, 1) == 1) {
+		if (vhost_driver_session_start())
+			goto error;
+	}
+
 	return data->port_id;
 
 error:
@@ -1215,6 +1199,11 @@ rte_pmd_vhost_remove(const char *name)
 
 	eth_dev_stop(eth_dev);
 
+	rte_vhost_driver_unregister(internal->iface_name);
+
+	if (rte_atomic16_sub_return(&nb_started_ports, 1) == 0)
+		vhost_driver_session_stop();
+
 	rte_free(vring_states[eth_dev->data->port_id]);
 	vring_states[eth_dev->data->port_id] = NULL;
 
-- 
2.1.4

[PATCH v4 2/2] net/vhost: emulate device start/stop behavior

[Charles (Chas) Williams]

.dev_start()/.dev_stop() roughly corresponds to the local device's port
being ready.  This is different from the remote client being connected
which is roughly link up or down.  Emulate the device start/stop behavior
by separately tracking the start/stop state to determine if we should
allow packets to be queued to/from the remote client.

Signed-off-by: Chas Williams <ciwillia@brocade.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 82 ++++++++++++++++++++++++---------------
 1 file changed, 51 insertions(+), 31 deletions(-)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index c669e79..0b5b80a 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -110,9 +110,11 @@ struct vhost_queue {
 };
 
 struct pmd_internal {
+	rte_atomic32_t dev_attached;
 	char *dev_name;
 	char *iface_name;
 	uint16_t max_queues;
+	rte_atomic32_t started;
 };
 
 struct internal_list {
@@ -490,6 +492,38 @@ find_internal_resource(char *ifname)
 	return list;
 }
 
+static void
+update_queuing_status(struct rte_eth_dev *dev)
+{
+	struct pmd_internal *internal = dev->data->dev_private;
+	struct vhost_queue *vq;
+	unsigned int i;
+	int allow_queuing = 1;
+
+	if (rte_atomic32_read(&internal->started) == 0 ||
+	    rte_atomic32_read(&internal->dev_attached) == 0)
+		allow_queuing = 0;
+
+	/* Wait until rx/tx_pkt_burst stops accessing vhost device */
+	for (i = 0; i < dev->data->nb_rx_queues; i++) {
+		vq = dev->data->rx_queues[i];
+		if (vq == NULL)
+			continue;
+		rte_atomic32_set(&vq->allow_queuing, allow_queuing);
+		while (rte_atomic32_read(&vq->while_queuing))
+			rte_pause();
+	}
+
+	for (i = 0; i < dev->data->nb_tx_queues; i++) {
+		vq = dev->data->tx_queues[i];
+		if (vq == NULL)
+			continue;
+		rte_atomic32_set(&vq->allow_queuing, allow_queuing);
+		while (rte_atomic32_read(&vq->while_queuing))
+			rte_pause();
+	}
+}
+
 static int
 new_device(int vid)
 {
@@ -541,18 +575,8 @@ new_device(int vid)
 
 	eth_dev->data->dev_link.link_status = ETH_LINK_UP;
 
-	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
-		vq = eth_dev->data->rx_queues[i];
-		if (vq == NULL)
-			continue;
-		rte_atomic32_set(&vq->allow_queuing, 1);
-	}
-	for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
-		vq = eth_dev->data->tx_queues[i];
-		if (vq == NULL)
-			continue;
-		rte_atomic32_set(&vq->allow_queuing, 1);
-	}
+	rte_atomic32_set(&internal->dev_attached, 1);
+	update_queuing_status(eth_dev);
 
 	RTE_LOG(INFO, PMD, "New connection established\n");
 
@@ -565,6 +589,7 @@ static void
 destroy_device(int vid)
 {
 	struct rte_eth_dev *eth_dev;
+	struct pmd_internal *internal;
 	struct vhost_queue *vq;
 	struct internal_list *list;
 	char ifname[PATH_MAX];
@@ -578,24 +603,10 @@ destroy_device(int vid)
 		return;
 	}
 	eth_dev = list->eth_dev;
+	internal = eth_dev->data->dev_private;
 
-	/* Wait until rx/tx_pkt_burst stops accessing vhost device */
-	for (i = 0; i < eth_dev->data->nb_rx_queues; i++) {
-		vq = eth_dev->data->rx_queues[i];
-		if (vq == NULL)
-			continue;
-		rte_atomic32_set(&vq->allow_queuing, 0);
-		while (rte_atomic32_read(&vq->while_queuing))
-			rte_pause();
-	}
-	for (i = 0; i < eth_dev->data->nb_tx_queues; i++) {
-		vq = eth_dev->data->tx_queues[i];
-		if (vq == NULL)
-			continue;
-		rte_atomic32_set(&vq->allow_queuing, 0);
-		while (rte_atomic32_read(&vq->while_queuing))
-			rte_pause();
-	}
+	rte_atomic32_set(&internal->dev_attached, 0);
+	update_queuing_status(eth_dev);
 
 	eth_dev->data->dev_link.link_status = ETH_LINK_DOWN;
 
@@ -769,14 +780,23 @@ vhost_driver_session_stop(void)
 }
 
 static int
-eth_dev_start(struct rte_eth_dev *dev __rte_unused)
+eth_dev_start(struct rte_eth_dev *dev)
 {
+	struct pmd_internal *internal = dev->data->dev_private;
+
+	rte_atomic32_set(&internal->started, 1);
+	update_queuing_status(dev);
+
 	return 0;
 }
 
 static void
-eth_dev_stop(struct rte_eth_dev *dev __rte_unused)
+eth_dev_stop(struct rte_eth_dev *dev)
 {
+	struct pmd_internal *internal = dev->data->dev_private;
+
+	rte_atomic32_set(&internal->started, 0);
+	update_queuing_status(dev);
 }
 
 static int
-- 
2.1.4

Re: [PATCH v4 1/2] net/vhost: create datagram sockets immediately

[Yuanhan Liu]

On Tue, Jan 03, 2017 at 11:22:42AM -0500, Charles (Chas) Williams wrote:
> If you create a vhost server device, it doesn't create the actual datagram
> socket until you call .dev_start().  If you call .dev_stop() is also
> deletes those sockets.  For QEMU clients, this is a problem since QEMU
> doesn't know how to re-attach to datagram sockets that have gone away.
> 
> To fix this, register and unregister the datagram sockets during device
> creation and removal.
> 
> Fixes: ee584e9710b9 ("vhost: add driver on top of the library")

Both patches applied to dpdk-next-virtio. Thanks!

Note that we prefer a title of "prefix: fix ..." for bug fixing patch.
For this reason, I have changed the title for you while apply:

    net/vhost: fix socket file being deleted on dev stop

Also, stable is cc'ed.

	--yliu