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
Following patches convert all the drivers.
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
---
drivers/vfio/mdev/mdev_core.c | 64 ++++++++++++++++++++++++++++-----
drivers/vfio/mdev/mdev_driver.c | 17 ++++++++-
include/linux/mdev.h | 3 ++
3 files changed, 75 insertions(+), 9 deletions(-)
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index ff8c1a84516698..51b8a9fcf866ad 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);
@@ -251,6 +255,43 @@ static void mdev_device_release(struct device *dev)
kfree(mdev);
}
+/*
+ * mdev drivers can refuse to bind during probe(), in this case we want to fail
+ * the creation of the mdev all the way back to sysfs. This is a weird model
+ * that doesn't fit in the driver core well, nor does it seem to appear any
+ * place else in the kernel, so use a simple hack.
+ */
+static int mdev_bind_driver(struct mdev_device *mdev)
+{
+ struct mdev_driver *drv = mdev->type->parent->ops->device_driver;
+ int ret;
+
+ if (!drv)
+ drv = &vfio_mdev_driver;
+
+ while (1) {
+ device_lock(&mdev->dev);
+ if (mdev->dev.driver == &drv->driver) {
+ ret = 0;
+ goto out_unlock;
+ }
+ if (mdev->probe_err) {
+ ret = mdev->probe_err;
+ goto out_unlock;
+ }
+ device_unlock(&mdev->dev);
+ ret = device_attach(&mdev->dev);
+ if (ret)
+ return ret;
+ mdev->probe_err = -EINVAL;
+ }
+ return 0;
+
+out_unlock:
+ device_unlock(&mdev->dev);
+ return ret;
+}
+
int mdev_device_create(struct mdev_type *type, const guid_t *uuid)
{
int ret;
@@ -296,14 +337,20 @@ 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;
+ ret = mdev_bind_driver(mdev);
+ if (ret)
+ goto out_del;
+
ret = mdev_create_sysfs_files(mdev);
if (ret)
goto out_del;
@@ -317,7 +364,8 @@ 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..6e96c023d7823d 100644
--- a/drivers/vfio/mdev/mdev_driver.c
+++ b/drivers/vfio/mdev/mdev_driver.c
@@ -49,7 +49,7 @@ static int mdev_probe(struct device *dev)
return ret;
if (drv->probe) {
- ret = drv->probe(mdev);
+ ret = mdev->probe_err = drv->probe(mdev);
if (ret)
mdev_detach_iommu(mdev);
}
@@ -71,10 +71,25 @@ static int mdev_remove(struct device *dev)
return 0;
}
+static int mdev_match(struct device *dev, struct device_driver *drv)
+{
+ struct mdev_device *mdev = to_mdev_device(dev);
+ struct mdev_driver *target = mdev->type->parent->ops->device_driver;
+
+ /*
+ * The ops specify the device driver to connect, fall back to the old
+ * shim driver if the driver hasn't been converted.
+ */
+ if (!target)
+ target = &vfio_mdev_driver;
+ return drv == &target->driver;
+}
+
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..49cc4f65120d57 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -19,6 +19,7 @@ struct mdev_device {
struct list_head next;
struct mdev_type *type;
struct device *iommu_device;
+ int probe_err;
bool active;
};
@@ -55,6 +56,7 @@ 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 +105,7 @@ 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
