[PATCH net-next v7 0/4] virtio-net: synchronize op/admin state

[PATCH net-next v7 0/4] virtio-net: synchronize op/admin state

[Jason Wang]

Hi All:

This series tries to synchronize the operstate with the admin state
which allows the lower virtio-net to propagate the link status to the
upper devices like macvlan.

This is done by toggling carrier during ndo_open/stop while doing
other necessary serialization about the carrier settings during probe.

While at it, also fix a race between probe and ndo_set_features as we
didn't initalize the guest offload setting under rtnl lock.

Changes since V6:

- Add fix tag

Changes since V5:

- Fix sevreal typos
- Include a new patch to synchronize probe with ndo_set_features

Changes since V4:

- do not update settings during ndo_open()
- do not try to canel config noticiation during probe() as core make
  sure the config notificaiton won't be triggered before probe is
  done.
- Tweak sevreal comments.

Changes since V3:

- when driver tries to enable config interrupt, check pending
  interrupt and execute the nofitication change callback if necessary
- do not unconditonally trigger the config space read
- do not set LINK_UP flag in ndo_open/close but depends on the
  notification change
- disable config change notification until ndo_open()
- read the link status under the rtnl_lock() to prevent a race with
  ndo_open()

Changes since V2:

- introduce config_driver_disabled and helpers
- schedule config change work unconditionally

Thanks


Jason Wang (4):
  virtio: rename virtio_config_enabled to virtio_config_core_enabled
  virtio: allow driver to disable the configure change notification
  virtio-net: synchronize operstate with admin state on up/down
  virtio-net: synchronize probe with ndo_set_features

 drivers/net/virtio_net.c | 78 +++++++++++++++++++++++++---------------
 drivers/virtio/virtio.c  | 59 +++++++++++++++++++++++-------
 include/linux/virtio.h   | 11 ++++--
 3 files changed, 105 insertions(+), 43 deletions(-)

-- 
2.31.1

[PATCH net-next v7 1/4] virtio: rename virtio_config_enabled to virtio_config_core_enabled

[Jason Wang]

Following patch will allow the config interrupt to be disabled by a
specific driver via another boolean. So this patch renames
virtio_config_enabled and relevant helpers to
virtio_config_core_enabled.

Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/virtio/virtio.c | 22 +++++++++++-----------
 include/linux/virtio.h  |  4 ++--
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index bc1f962e483b..6b692b0fa578 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -127,7 +127,7 @@ static void __virtio_config_changed(struct virtio_device *dev)
 {
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 
-	if (!dev->config_enabled)
+	if (!dev->config_core_enabled)
 		dev->config_change_pending = true;
 	else if (drv && drv->config_changed)
 		drv->config_changed(dev);
@@ -143,17 +143,17 @@ void virtio_config_changed(struct virtio_device *dev)
 }
 EXPORT_SYMBOL_GPL(virtio_config_changed);
 
-static void virtio_config_disable(struct virtio_device *dev)
+static void virtio_config_core_disable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
-	dev->config_enabled = false;
+	dev->config_core_enabled = false;
 	spin_unlock_irq(&dev->config_lock);
 }
 
-static void virtio_config_enable(struct virtio_device *dev)
+static void virtio_config_core_enable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
-	dev->config_enabled = true;
+	dev->config_core_enabled = true;
 	if (dev->config_change_pending)
 		__virtio_config_changed(dev);
 	dev->config_change_pending = false;
@@ -316,7 +316,7 @@ static int virtio_dev_probe(struct device *_d)
 	if (drv->scan)
 		drv->scan(dev);
 
-	virtio_config_enable(dev);
+	virtio_config_core_enable(dev);
 
 	return 0;
 
@@ -331,7 +331,7 @@ static void virtio_dev_remove(struct device *_d)
 	struct virtio_device *dev = dev_to_virtio(_d);
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 
-	virtio_config_disable(dev);
+	virtio_config_core_disable(dev);
 
 	drv->remove(dev);
 
@@ -443,7 +443,7 @@ int register_virtio_device(struct virtio_device *dev)
 		goto out_ida_remove;
 
 	spin_lock_init(&dev->config_lock);
-	dev->config_enabled = false;
+	dev->config_core_enabled = false;
 	dev->config_change_pending = false;
 
 	INIT_LIST_HEAD(&dev->vqs);
@@ -500,14 +500,14 @@ int virtio_device_freeze(struct virtio_device *dev)
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 	int ret;
 
-	virtio_config_disable(dev);
+	virtio_config_core_disable(dev);
 
 	dev->failed = dev->config->get_status(dev) & VIRTIO_CONFIG_S_FAILED;
 
 	if (drv && drv->freeze) {
 		ret = drv->freeze(dev);
 		if (ret) {
-			virtio_config_enable(dev);
+			virtio_config_core_enable(dev);
 			return ret;
 		}
 	}
@@ -557,7 +557,7 @@ int virtio_device_restore(struct virtio_device *dev)
 	if (!(dev->config->get_status(dev) & VIRTIO_CONFIG_S_DRIVER_OK))
 		virtio_device_ready(dev);
 
-	virtio_config_enable(dev);
+	virtio_config_core_enable(dev);
 
 	return 0;
 
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 4b16844c6bc2..de6d3cc176d9 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -118,7 +118,7 @@ struct virtio_admin_cmd {
  * struct virtio_device - representation of a device using virtio
  * @index: unique position on the virtio bus
  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
- * @config_enabled: configuration change reporting enabled
+ * @config_core_enabled: configuration change reporting enabled by core
  * @config_change_pending: configuration change reported while disabled
  * @config_lock: protects configuration change reporting
  * @vqs_list_lock: protects @vqs.
@@ -135,7 +135,7 @@ struct virtio_admin_cmd {
 struct virtio_device {
 	int index;
 	bool failed;
-	bool config_enabled;
+	bool config_core_enabled;
 	bool config_change_pending;
 	spinlock_t config_lock;
 	spinlock_t vqs_list_lock;
-- 
2.31.1

[PATCH net-next v7 2/4] virtio: allow driver to disable the configure change notification

[Jason Wang]

Sometime, it would be useful to disable the configure change
notification from the driver. So this patch allows this by introducing
a variable config_change_driver_disabled and only allow the configure
change notification callback to be triggered when it is allowed by
both the virtio core and the driver. It is set to false by default to
hold the current semantic so we don't need to change any drivers.

The first user for this would be virtio-net.

Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/virtio/virtio.c | 39 ++++++++++++++++++++++++++++++++++++---
 include/linux/virtio.h  |  7 +++++++
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 6b692b0fa578..b9095751e43b 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -127,10 +127,12 @@ static void __virtio_config_changed(struct virtio_device *dev)
 {
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 
-	if (!dev->config_core_enabled)
+	if (!dev->config_core_enabled || dev->config_driver_disabled)
 		dev->config_change_pending = true;
-	else if (drv && drv->config_changed)
+	else if (drv && drv->config_changed) {
 		drv->config_changed(dev);
+		dev->config_change_pending = false;
+	}
 }
 
 void virtio_config_changed(struct virtio_device *dev)
@@ -143,6 +145,38 @@ void virtio_config_changed(struct virtio_device *dev)
 }
 EXPORT_SYMBOL_GPL(virtio_config_changed);
 
+/**
+ * virtio_config_driver_disable - disable config change reporting by drivers
+ * @dev: the device to reset
+ *
+ * This is only allowed to be called by a driver and disabling can't
+ * be nested.
+ */
+void virtio_config_driver_disable(struct virtio_device *dev)
+{
+	spin_lock_irq(&dev->config_lock);
+	dev->config_driver_disabled = true;
+	spin_unlock_irq(&dev->config_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_config_driver_disable);
+
+/**
+ * virtio_config_driver_enable - enable config change reporting by drivers
+ * @dev: the device to reset
+ *
+ * This is only allowed to be called by a driver and enabling can't
+ * be nested.
+ */
+void virtio_config_driver_enable(struct virtio_device *dev)
+{
+	spin_lock_irq(&dev->config_lock);
+	dev->config_driver_disabled = false;
+	if (dev->config_change_pending)
+		__virtio_config_changed(dev);
+	spin_unlock_irq(&dev->config_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_config_driver_enable);
+
 static void virtio_config_core_disable(struct virtio_device *dev)
 {
 	spin_lock_irq(&dev->config_lock);
@@ -156,7 +190,6 @@ static void virtio_config_core_enable(struct virtio_device *dev)
 	dev->config_core_enabled = true;
 	if (dev->config_change_pending)
 		__virtio_config_changed(dev);
-	dev->config_change_pending = false;
 	spin_unlock_irq(&dev->config_lock);
 }
 
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index de6d3cc176d9..306137a15d07 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -119,6 +119,8 @@ struct virtio_admin_cmd {
  * @index: unique position on the virtio bus
  * @failed: saved value for VIRTIO_CONFIG_S_FAILED bit (for restore)
  * @config_core_enabled: configuration change reporting enabled by core
+ * @config_driver_disabled: configuration change reporting disabled by
+ *                          a driver
  * @config_change_pending: configuration change reported while disabled
  * @config_lock: protects configuration change reporting
  * @vqs_list_lock: protects @vqs.
@@ -136,6 +138,7 @@ struct virtio_device {
 	int index;
 	bool failed;
 	bool config_core_enabled;
+	bool config_driver_disabled;
 	bool config_change_pending;
 	spinlock_t config_lock;
 	spinlock_t vqs_list_lock;
@@ -166,6 +169,10 @@ void __virtqueue_break(struct virtqueue *_vq);
 void __virtqueue_unbreak(struct virtqueue *_vq);
 
 void virtio_config_changed(struct virtio_device *dev);
+
+void virtio_config_driver_disable(struct virtio_device *dev);
+void virtio_config_driver_enable(struct virtio_device *dev);
+
 #ifdef CONFIG_PM_SLEEP
 int virtio_device_freeze(struct virtio_device *dev);
 int virtio_device_restore(struct virtio_device *dev);
-- 
2.31.1

[PATCH net-next v7 3/4] virtio-net: synchronize operstate with admin state on up/down

[Jason Wang]

This patch synchronizes operstate with admin state per RFC2863.

This is done by trying to toggle the carrier upon open/close and
synchronize with the config change work. This allows to propagate
status correctly to stacked devices like:

ip link add link enp0s3 macvlan0 type macvlan
ip link set link enp0s3 down
ip link show

Before this patch:

3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
......
5: macvlan0@enp0s3: <BROADCAST,MULTICAST,UP,LOWER_UP,M-DOWN> mtu 1500 qdisc noqueue state UP mode DEFAULT group default qlen 1000
    link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff

After this patch:

3: enp0s3: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000
    link/ether 00:00:05:00:00:09 brd ff:ff:ff:ff:ff:ff
...
5: macvlan0@enp0s3: <NO-CARRIER,BROADCAST,MULTICAST,UP,M-DOWN> mtu 1500 qdisc noqueue state LOWERLAYERDOWN mode DEFAULT group default qlen 1000
    link/ether b2:a9:c5:04:da:53 brd ff:ff:ff:ff:ff:ff

Cc: Venkat Venkatsubra <venkat.x.venkatsubra@oracle.com>
Cc: Gia-Khanh Nguyen <gia-khanh.nguyen@oracle.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 78 +++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 28 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 3f10c72743e9..55b712a71e63 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2885,6 +2885,25 @@ static void virtnet_cancel_dim(struct virtnet_info *vi, struct dim *dim)
 	net_dim_work_cancel(dim);
 }
 
+static void virtnet_update_settings(struct virtnet_info *vi)
+{
+	u32 speed;
+	u8 duplex;
+
+	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
+		return;
+
+	virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
+
+	if (ethtool_validate_speed(speed))
+		vi->speed = speed;
+
+	virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
+
+	if (ethtool_validate_duplex(duplex))
+		vi->duplex = duplex;
+}
+
 static int virtnet_open(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -2903,6 +2922,15 @@ static int virtnet_open(struct net_device *dev)
 			goto err_enable_qp;
 	}
 
+	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
+		if (vi->status & VIRTIO_NET_S_LINK_UP)
+			netif_carrier_on(vi->dev);
+		virtio_config_driver_enable(vi->vdev);
+	} else {
+		vi->status = VIRTIO_NET_S_LINK_UP;
+		netif_carrier_on(dev);
+	}
+
 	return 0;
 
 err_enable_qp:
@@ -3381,12 +3409,22 @@ static int virtnet_close(struct net_device *dev)
 	disable_delayed_refill(vi);
 	/* Make sure refill_work doesn't re-enable napi! */
 	cancel_delayed_work_sync(&vi->refill);
+	/* Prevent the config change callback from changing carrier
+	 * after close
+	 */
+	virtio_config_driver_disable(vi->vdev);
+	/* Stop getting status/speed updates: we don't care until next
+	 * open
+	 */
+	cancel_work_sync(&vi->config_work);
 
 	for (i = 0; i < vi->max_queue_pairs; i++) {
 		virtnet_disable_queue_pair(vi, i);
 		virtnet_cancel_dim(vi, &vi->rq[i].dim);
 	}
 
+	netif_carrier_off(dev);
+
 	return 0;
 }
 
@@ -5095,25 +5133,6 @@ static void virtnet_init_settings(struct net_device *dev)
 	vi->duplex = DUPLEX_UNKNOWN;
 }
 
-static void virtnet_update_settings(struct virtnet_info *vi)
-{
-	u32 speed;
-	u8 duplex;
-
-	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_SPEED_DUPLEX))
-		return;
-
-	virtio_cread_le(vi->vdev, struct virtio_net_config, speed, &speed);
-
-	if (ethtool_validate_speed(speed))
-		vi->speed = speed;
-
-	virtio_cread_le(vi->vdev, struct virtio_net_config, duplex, &duplex);
-
-	if (ethtool_validate_duplex(duplex))
-		vi->duplex = duplex;
-}
-
 static u32 virtnet_get_rxfh_key_size(struct net_device *dev)
 {
 	return ((struct virtnet_info *)netdev_priv(dev))->rss_key_size;
@@ -6524,6 +6543,9 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free_failover;
 	}
 
+	/* Disable config change notification until ndo_open. */
+	virtio_config_driver_disable(vi->vdev);
+
 	virtio_device_ready(vdev);
 
 	virtnet_set_queues(vi, vi->curr_queue_pairs);
@@ -6573,25 +6595,25 @@ static int virtnet_probe(struct virtio_device *vdev)
 		vi->device_stats_cap = le64_to_cpu(v);
 	}
 
-	rtnl_unlock();
-
-	err = virtnet_cpu_notif_add(vi);
-	if (err) {
-		pr_debug("virtio_net: registering cpu notifier failed\n");
-		goto free_unregister_netdev;
-	}
-
 	/* Assume link up if device can't report link status,
 	   otherwise get link status from config. */
 	netif_carrier_off(dev);
 	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
-		schedule_work(&vi->config_work);
+		virtnet_config_changed_work(&vi->config_work);
 	} else {
 		vi->status = VIRTIO_NET_S_LINK_UP;
 		virtnet_update_settings(vi);
 		netif_carrier_on(dev);
 	}
 
+	rtnl_unlock();
+
+	err = virtnet_cpu_notif_add(vi);
+	if (err) {
+		pr_debug("virtio_net: registering cpu notifier failed\n");
+		goto free_unregister_netdev;
+	}
+
 	for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
 		if (virtio_has_feature(vi->vdev, guest_offloads[i]))
 			set_bit(guest_offloads[i], &vi->guest_offloads);
-- 
2.31.1

[PATCH net-next v7 4/4] virtio-net: synchronize probe with ndo_set_features

[Jason Wang]

We calculate guest offloads during probe without the protection of
rtnl_lock. This lead to race between probe and ndo_set_features. Fix
this by moving the calculation under the rtnl_lock.

Fixes: 3f93522ffab2 ("virtio-net: switch off offloads on demand if possible on XDP set")
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/virtio_net.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 55b712a71e63..6c79fc43fa31 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -6606,6 +6606,11 @@ static int virtnet_probe(struct virtio_device *vdev)
 		netif_carrier_on(dev);
 	}
 
+	for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
+		if (virtio_has_feature(vi->vdev, guest_offloads[i]))
+			set_bit(guest_offloads[i], &vi->guest_offloads);
+	vi->guest_offloads_capable = vi->guest_offloads;
+
 	rtnl_unlock();
 
 	err = virtnet_cpu_notif_add(vi);
@@ -6614,11 +6619,6 @@ static int virtnet_probe(struct virtio_device *vdev)
 		goto free_unregister_netdev;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(guest_offloads); i++)
-		if (virtio_has_feature(vi->vdev, guest_offloads[i]))
-			set_bit(guest_offloads[i], &vi->guest_offloads);
-	vi->guest_offloads_capable = vi->guest_offloads;
-
 	pr_debug("virtnet: registered device %s with %d RX and TX vq's\n",
 		 dev->name, max_queue_pairs);
 
-- 
2.31.1

Re: [PATCH net-next v7 0/4] virtio-net: synchronize op/admin state

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 14 Aug 2024 13:22:24 +0800 you wrote:
> Hi All:
> 
> This series tries to synchronize the operstate with the admin state
> which allows the lower virtio-net to propagate the link status to the
> upper devices like macvlan.
> 
> This is done by toggling carrier during ndo_open/stop while doing
> other necessary serialization about the carrier settings during probe.
> 
> [...]

Here is the summary with links:
  - [net-next,v7,1/4] virtio: rename virtio_config_enabled to virtio_config_core_enabled
    https://git.kernel.org/netdev/net-next/c/0cb70ee4a6ee
  - [net-next,v7,2/4] virtio: allow driver to disable the configure change notification
    https://git.kernel.org/netdev/net-next/c/224de6f886f8
  - [net-next,v7,3/4] virtio-net: synchronize operstate with admin state on up/down
    https://git.kernel.org/netdev/net-next/c/df28de7b0050
  - [net-next,v7,4/4] virtio-net: synchronize probe with ndo_set_features
    https://git.kernel.org/netdev/net-next/c/c392d6019398

You are awesome, thank you!
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