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From: Jason Gunthorpe <jgg@nvidia.com>
To: Alex Williamson <alex.williamson@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>,
	kvm@vger.kernel.org, Kirti Wankhede <kwankhede@nvidia.com>
Subject: [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind
Date: Mon,  7 Jun 2021 21:55:49 -0300	[thread overview]
Message-ID: <7-v1-324b2038f212+1041f1-vfio3a_jgg@nvidia.com> (raw)
In-Reply-To: <0-v1-324b2038f212+1041f1-vfio3a_jgg@nvidia.com>

This allows a mdev driver to opt out of using vfio_mdev.c, instead the
driver will provide a 'struct mdev_driver' and register directly with the
driver core.

Much of mdev_parent_ops becomes unused in this mode:
- create()/remove() are done via the mdev_driver probe()/remove()
- mdev_attr_groups becomes mdev_driver driver.dev_groups
- Wrapper function callbacks are replaced with the same ones from
  struct vfio_device_ops

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/mdev/mdev_core.c   | 30 ++++++++++++++++++++++--------
 drivers/vfio/mdev/mdev_driver.c | 10 ++++++++++
 include/linux/mdev.h            |  2 ++
 3 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index ff8c1a84516698..e4581ec093a6a6 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -94,9 +94,11 @@ static void mdev_device_remove_common(struct mdev_device *mdev)
 	mdev_remove_sysfs_files(mdev);
 	device_del(&mdev->dev);
 	lockdep_assert_held(&parent->unreg_sem);
-	ret = parent->ops->remove(mdev);
-	if (ret)
-		dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
+	if (parent->ops->remove) {
+		ret = parent->ops->remove(mdev);
+		if (ret)
+			dev_err(&mdev->dev, "Remove failed: err=%d\n", ret);
+	}
 
 	/* Balances with device_initialize() */
 	put_device(&mdev->dev);
@@ -127,7 +129,9 @@ int mdev_register_device(struct device *dev, const struct mdev_parent_ops *ops)
 	char *envp[] = { env_string, NULL };
 
 	/* check for mandatory ops */
-	if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
+	if (!ops || !ops->supported_type_groups)
+		return -EINVAL;
+	if (!ops->device_driver && (!ops->create || !ops->remove))
 		return -EINVAL;
 
 	dev = get_device(dev);
@@ -256,6 +260,7 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 	int ret;
 	struct mdev_device *mdev, *tmp;
 	struct mdev_parent *parent = type->parent;
+	struct mdev_driver *drv = parent->ops->device_driver;
 
 	mutex_lock(&mdev_list_lock);
 
@@ -296,14 +301,22 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 		goto out_put_device;
 	}
 
-	ret = parent->ops->create(mdev);
-	if (ret)
-		goto out_unlock;
+	if (parent->ops->create) {
+		ret = parent->ops->create(mdev);
+		if (ret)
+			goto out_unlock;
+	}
 
 	ret = device_add(&mdev->dev);
 	if (ret)
 		goto out_remove;
 
+	if (!drv)
+		drv = &vfio_mdev_driver;
+	ret = device_driver_attach(&drv->driver, &mdev->dev);
+	if (ret)
+		goto out_del;
+
 	ret = mdev_create_sysfs_files(mdev);
 	if (ret)
 		goto out_del;
@@ -317,7 +330,8 @@ int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
 out_del:
 	device_del(&mdev->dev);
 out_remove:
-	parent->ops->remove(mdev);
+	if (parent->ops->remove)
+		parent->ops->remove(mdev);
 out_unlock:
 	up_read(&parent->unreg_sem);
 out_put_device:
diff --git a/drivers/vfio/mdev/mdev_driver.c b/drivers/vfio/mdev/mdev_driver.c
index 041699571b7e55..c368ec824e2b5c 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -71,10 +71,20 @@ static int mdev_remove(struct device *dev)
 	return 0;
 }
 
+static int mdev_match(struct device *dev, struct device_driver *drv)
+{
+	/*
+	 * No drivers automatically match. Drivers are only bound by explicit
+	 * device_driver_attach()
+	 */
+	return 0;
+}
+
 struct bus_type mdev_bus_type = {
 	.name		= "mdev",
 	.probe		= mdev_probe,
 	.remove		= mdev_remove,
+	.match		= mdev_match,
 };
 EXPORT_SYMBOL_GPL(mdev_bus_type);
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 1fb34ea394ad46..3a38598c260559 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -55,6 +55,7 @@ struct device *mtype_get_parent_dev(struct mdev_type *mtype);
  * register the device to mdev module.
  *
  * @owner:		The module owner.
+ * @device_driver:	Which device driver to probe() on newly created devices
  * @dev_attr_groups:	Attributes of the parent device.
  * @mdev_attr_groups:	Attributes of the mediated device.
  * @supported_type_groups: Attributes to define supported types. It is mandatory
@@ -103,6 +104,7 @@ struct device *mtype_get_parent_dev(struct mdev_type *mtype);
  **/
 struct mdev_parent_ops {
 	struct module   *owner;
+	struct mdev_driver *device_driver;
 	const struct attribute_group **dev_attr_groups;
 	const struct attribute_group **mdev_attr_groups;
 	struct attribute_group **supported_type_groups;
-- 
2.31.1


  parent reply	other threads:[~2021-06-08  0:56 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-08  0:55 [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Jason Gunthorpe
2021-06-08  0:55 ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 01/10] driver core: Do not continue searching for drivers if deferred probe is used Jason Gunthorpe
2021-06-08  5:51   ` Christoph Hellwig
2021-06-08  6:44   ` Greg Kroah-Hartman
2021-06-08 12:16     ` Jason Gunthorpe
2021-06-08 13:13       ` Greg Kroah-Hartman
2021-06-08 13:53         ` Jason Gunthorpe
2021-06-08  7:35   ` Greg Kroah-Hartman
2021-06-08 12:17     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 02/10] driver core: Pull required checks into driver_probe_device() Jason Gunthorpe
2021-06-08  5:59   ` Christoph Hellwig
2021-06-08 12:21     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Jason Gunthorpe
2021-06-08  6:07   ` Christoph Hellwig
2021-06-08 23:53     ` Jason Gunthorpe
2021-06-08  6:47   ` Greg Kroah-Hartman
2021-06-08 12:30     ` Jason Gunthorpe
2021-06-08 13:16       ` Greg Kroah-Hartman
2021-06-08 14:03         ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during " Jason Gunthorpe
2021-06-08  6:14   ` Christoph Hellwig
2021-06-08  7:37   ` Greg Kroah-Hartman
2021-06-08  0:55 ` [PATCH 05/10] driver core: Export device_driver_attach() Jason Gunthorpe
2021-06-08  6:19   ` Christoph Hellwig
2021-06-08 12:33     ` Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Jason Gunthorpe
2021-06-08  0:55   ` [Intel-gfx] " Jason Gunthorpe
2021-06-08  6:20   ` Christoph Hellwig
2021-06-08  6:20     ` [Intel-gfx] " Christoph Hellwig
2021-06-11 12:40   ` Cornelia Huck
2021-06-11 12:40     ` [Intel-gfx] " Cornelia Huck
2021-06-14 12:35     ` Jason Gunthorpe
2021-06-14 12:35       ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 12:35       ` Jason Gunthorpe
2021-06-08  0:55 ` Jason Gunthorpe [this message]
2021-06-08  6:21   ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig
2021-06-08  0:55 ` [PATCH 08/10] vfio/mtty: Convert to use vfio_register_group_dev() Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 09/10] vfio/mdpy: " Jason Gunthorpe
2021-06-08  0:55 ` [PATCH 10/10] vfio/mbochs: " Jason Gunthorpe
2021-06-08  6:22 ` [PATCH 00/10] Allow mdev drivers to directly create the vfio_device Christoph Hellwig
2021-06-08  6:22   ` [Intel-gfx] " Christoph Hellwig
2021-06-14 14:34 ` Kirti Wankhede
2021-06-14 14:34   ` [Intel-gfx] " Kirti Wankhede
2021-06-14 14:34   ` Kirti Wankhede
2021-06-14 14:36   ` Jason Gunthorpe
2021-06-14 14:36     ` [Intel-gfx] " Jason Gunthorpe
2021-06-14 14:36     ` Jason Gunthorpe
2021-06-14 15:08 Allow mdev drivers to directly create the vfio_device (v2 / alternative) Christoph Hellwig
2021-06-14 15:08 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig
2021-06-15 10:54   ` Cornelia Huck
2021-06-15 10:54     ` Cornelia Huck
2021-06-15 13:35 Allow mdev drivers to directly create the vfio_device (v3) Christoph Hellwig
2021-06-15 13:35 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig
2021-06-15 14:06   ` Cornelia Huck
2021-06-15 14:06     ` Cornelia Huck
2021-06-15 14:11   ` Greg Kroah-Hartman
2021-06-15 14:11     ` Greg Kroah-Hartman
2021-06-16  0:00     ` Jason Gunthorpe
2021-06-16  0:00       ` Jason Gunthorpe
2021-06-16  6:39       ` Greg Kroah-Hartman
2021-06-16  6:39         ` Greg Kroah-Hartman
2021-06-16 20:20   ` Kirti Wankhede
2021-06-16 20:20     ` Kirti Wankhede
2021-06-17 14:22 Allow mdev drivers to directly create the vfio_device (v4) Christoph Hellwig
2021-06-17 14:22 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Christoph Hellwig

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