RE: [RFC PATCH 1/2] mdev: device id support

From: Tian, Kevin
Date: Tue Sep 17 2019 - 03:56:07 EST

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> From: Jason Wang
> Sent: Thursday, September 12, 2019 5:40 PM
>
> Mdev bus only support vfio driver right now, so it doesn't implement
> match method. But in the future, we may add drivers other than vfio,
> one example is virtio-mdev[1] driver. This means we need to add device
> id support in bus match method to pair the mdev device and mdev driver
> correctly.

"device id" sound a bit confusing to me - it usually means something
unique to each device, while here it is used to indicate expected driver
types (vfio, virtio, etc.). but using "bus id" is also not good - we have
only one mdev bus here. Then what about "class id"?

>
> So this patch add id_table to mdev_driver and id for mdev parent, and
> implement the match method for mdev bus.
>
> [1] https://lkml.org/lkml/2019/9/10/135
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +-
> drivers/s390/cio/vfio_ccw_ops.c | 2 +-
> drivers/s390/crypto/vfio_ap_ops.c | 3 ++-
> drivers/vfio/mdev/mdev_core.c | 14 ++++++++++++--
> drivers/vfio/mdev/mdev_driver.c | 14 ++++++++++++++
> drivers/vfio/mdev/mdev_private.h | 1 +
> drivers/vfio/mdev/vfio_mdev.c | 6 ++++++
> include/linux/mdev.h | 6 +++++-
> include/linux/mod_devicetable.h | 6 ++++++
> samples/vfio-mdev/mbochs.c | 2 +-
> samples/vfio-mdev/mdpy.c | 2 +-
> samples/vfio-mdev/mtty.c | 2 +-
> 12 files changed, 51 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c
> b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 23aa3e50cbf8..19d51a35f019 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -1625,7 +1625,7 @@ static int kvmgt_host_init(struct device *dev, void
> *gvt, const void *ops)
> return -EFAULT;
> intel_vgpu_ops.supported_type_groups = kvm_vgpu_type_groups;
>
> - return mdev_register_device(dev, &intel_vgpu_ops);
> + return mdev_register_vfio_device(dev, &intel_vgpu_ops);
> }
>
> static void kvmgt_host_exit(struct device *dev)
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c
> b/drivers/s390/cio/vfio_ccw_ops.c
> index 5eb61116ca6f..f87d9409e290 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -578,7 +578,7 @@ static const struct mdev_parent_ops
> vfio_ccw_mdev_ops = {
>
> int vfio_ccw_mdev_reg(struct subchannel *sch)
> {
> - return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
> + return mdev_register_vfio_device(&sch->dev,
> &vfio_ccw_mdev_ops);
> }
>
> void vfio_ccw_mdev_unreg(struct subchannel *sch)
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c
> b/drivers/s390/crypto/vfio_ap_ops.c
> index 0604b49a4d32..eacbde3c7a97 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -1295,7 +1295,8 @@ int vfio_ap_mdev_register(void)
> {
> atomic_set(&matrix_dev->available_instances,
> MAX_ZDEV_ENTRIES_EXT);
>
> - return mdev_register_device(&matrix_dev->device,
> &vfio_ap_matrix_ops);
> + return mdev_register_vfio_device(&matrix_dev->device,
> + &vfio_ap_matrix_ops);
> }
>
> void vfio_ap_mdev_unregister(void)
> diff --git a/drivers/vfio/mdev/mdev_core.c
> b/drivers/vfio/mdev/mdev_core.c
> index b558d4cfd082..fc07ff3ebe96 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -135,11 +135,14 @@ static int mdev_device_remove_cb(struct device
> *dev, void *data)
> * mdev_register_device : Register a device
> * @dev: device structure representing parent device.
> * @ops: Parent device operation structure to be registered.
> + * @id: device id.
> *
> * Add device to list of registered parent devices.
> * Returns a negative value on error, otherwise 0.
> */
> -int mdev_register_device(struct device *dev, const struct
> mdev_parent_ops *ops)
> +int mdev_register_device(struct device *dev,
> + const struct mdev_parent_ops *ops,
> + u8 id)
> {
> int ret;
> struct mdev_parent *parent;
> @@ -175,6 +178,7 @@ int mdev_register_device(struct device *dev, const
> struct mdev_parent_ops *ops)
>
> parent->dev = dev;
> parent->ops = ops;
> + parent->device_id = id;
>
> if (!mdev_bus_compat_class) {
> mdev_bus_compat_class =
> class_compat_register("mdev_bus");
> @@ -208,7 +212,13 @@ int mdev_register_device(struct device *dev, const
> struct mdev_parent_ops *ops)
> put_device(dev);
> return ret;
> }
> -EXPORT_SYMBOL(mdev_register_device);
> +
> +int mdev_register_vfio_device(struct device *dev,
> + const struct mdev_parent_ops *ops)
> +{
> + return mdev_register_device(dev, ops, MDEV_ID_VFIO);
> +}
> +EXPORT_SYMBOL(mdev_register_vfio_device);
>
> /*
> * mdev_unregister_device : Unregister a parent device
> diff --git a/drivers/vfio/mdev/mdev_driver.c
> b/drivers/vfio/mdev/mdev_driver.c
> index 0d3223aee20b..fd5e9541d18e 100644
> --- a/drivers/vfio/mdev/mdev_driver.c
> +++ b/drivers/vfio/mdev/mdev_driver.c
> @@ -69,8 +69,22 @@ static int mdev_remove(struct device *dev)
> return 0;
> }
>
> +static int mdev_match(struct device *dev, struct device_driver *drv)
> +{
> + unsigned int i;
> + struct mdev_device *mdev = to_mdev_device(dev);
> + struct mdev_driver *mdrv = to_mdev_driver(drv);
> + const struct mdev_device_id *ids = mdrv->id_table;
> +
> + for (i = 0; ids[i].id; i++)
> + if (ids[i].id == mdev->parent->device_id)
> + return 1;
> + return 0;
> +}
> +
> struct bus_type mdev_bus_type = {
> .name = "mdev",
> + .match = mdev_match,
> .probe = mdev_probe,
> .remove = mdev_remove,
> };
> diff --git a/drivers/vfio/mdev/mdev_private.h
> b/drivers/vfio/mdev/mdev_private.h
> index 7d922950caaf..7fc8153671e0 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -22,6 +22,7 @@ struct mdev_parent {
> struct list_head type_list;
> /* Synchronize device creation/removal with parent unregistration
> */
> struct rw_semaphore unreg_sem;
> + u8 device_id;
> };
>
> struct mdev_device {
> diff --git a/drivers/vfio/mdev/vfio_mdev.c
> b/drivers/vfio/mdev/vfio_mdev.c
> index 30964a4e0a28..887c57f10880 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -120,10 +120,16 @@ static void vfio_mdev_remove(struct device *dev)
> vfio_del_group_dev(dev);
> }
>
> +static struct mdev_device_id id_table[] = {
> + { MDEV_ID_VFIO },
> + { 0 },
> +};
> +
> static struct mdev_driver vfio_mdev_driver = {
> .name = "vfio_mdev",
> .probe = vfio_mdev_probe,
> .remove = vfio_mdev_remove,
> + .id_table = id_table,
> };
>
> static int __init vfio_mdev_init(void)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 0ce30ca78db0..f85045392120 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -118,6 +118,7 @@ struct mdev_type_attribute
> mdev_type_attr_##_name = \
> * @probe: called when new device created
> * @remove: called when device removed
> * @driver: device driver structure
> + * @id_table: the ids serviced by this driver.
> *
> **/
> struct mdev_driver {
> @@ -125,6 +126,7 @@ struct mdev_driver {
> int (*probe)(struct device *dev);
> void (*remove)(struct device *dev);
> struct device_driver driver;
> + const struct mdev_device_id *id_table;
> };
>
> #define to_mdev_driver(drv) container_of(drv, struct mdev_driver, driver)
> @@ -135,7 +137,7 @@ const guid_t *mdev_uuid(struct mdev_device
> *mdev);
>
> extern struct bus_type mdev_bus_type;
>
> -int mdev_register_device(struct device *dev, const struct
> mdev_parent_ops *ops);
> +int mdev_register_vfio_device(struct device *dev, const struct
> mdev_parent_ops *ops);
> void mdev_unregister_device(struct device *dev);
>
> int mdev_register_driver(struct mdev_driver *drv, struct module *owner);
> @@ -145,4 +147,6 @@ struct device *mdev_parent_dev(struct
> mdev_device *mdev);
> struct device *mdev_dev(struct mdev_device *mdev);
> struct mdev_device *mdev_from_dev(struct device *dev);
>
> +#define MDEV_ID_VFIO 1 /* VFIO device */
> +
> #endif /* MDEV_H */
> diff --git a/include/linux/mod_devicetable.h
> b/include/linux/mod_devicetable.h
> index 5714fd35a83c..f1fc143df042 100644
> --- a/include/linux/mod_devicetable.h
> +++ b/include/linux/mod_devicetable.h
> @@ -821,4 +821,10 @@ struct wmi_device_id {
> const void *context;
> };
>
> +/* MDEV */
> +
> +struct mdev_device_id {
> + __u8 id;
> +};
> +
> #endif /* LINUX_MOD_DEVICETABLE_H */
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index ac5c8c17b1ff..71a4469be85d 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -1468,7 +1468,7 @@ static int __init mbochs_dev_init(void)
> if (ret)
> goto failed2;
>
> - ret = mdev_register_device(&mbochs_dev, &mdev_fops);
> + ret = mdev_register_vfio_device(&mbochs_dev, &mdev_fops);
> if (ret)
> goto failed3;
>
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index cc86bf6566e4..d3029dd27d91 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -775,7 +775,7 @@ static int __init mdpy_dev_init(void)
> if (ret)
> goto failed2;
>
> - ret = mdev_register_device(&mdpy_dev, &mdev_fops);
> + ret = mdev_register_vfio_device(&mdpy_dev, &mdev_fops);
> if (ret)
> goto failed3;
>
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 92e770a06ea2..744c88a6b22c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -1468,7 +1468,7 @@ static int __init mtty_dev_init(void)
> if (ret)
> goto failed2;
>
> - ret = mdev_register_device(&mtty_dev.dev, &mdev_fops);
> + ret = mdev_register_vfio_device(&mtty_dev.dev, &mdev_fops);
> if (ret)
> goto failed3;
>
> --
> 2.19.1
>
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> intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev

Next message: Arnd Bergmann: "Re: [PATCH] nvmem: core: fix nvmem_cell_write inline function"
Previous message: Takashi Iwai: "Re: [PATCH] ALSA: usb-audio: Add Hiby device family to quirks for native DSD support"
Next in thread: Jason Wang: "Re: [RFC PATCH 1/2] mdev: device id support"
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