On Tue, 24 Sep 2019 21:53:29 +0800
Jason Wang <jasowang@xxxxxxxxxx> wrote:
> Currently, except for the create and remove, the rest of
> mdev_parent_ops is designed for vfio-mdev driver only and may not help
> for kernel mdev driver. With the help of class id, this patch
> introduces device specific callbacks inside mdev_device
> structure. This allows different set of callback to be used by
> vfio-mdev and virtio-mdev.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> .../driver-api/vfio-mediated-device.rst | 4 +-
> MAINTAINERS | 1 +
> drivers/gpu/drm/i915/gvt/kvmgt.c | 17 +++---
> drivers/s390/cio/vfio_ccw_ops.c | 17 ++++--
> drivers/s390/crypto/vfio_ap_ops.c | 13 +++--
> drivers/vfio/mdev/mdev_core.c | 12 +++++
> drivers/vfio/mdev/mdev_private.h | 1 +
> drivers/vfio/mdev/vfio_mdev.c | 37 ++++++-------
> include/linux/mdev.h | 42 ++++-----------
> include/linux/vfio_mdev.h | 52 +++++++++++++++++++
> samples/vfio-mdev/mbochs.c | 19 ++++---
> samples/vfio-mdev/mdpy.c | 19 ++++---
> samples/vfio-mdev/mtty.c | 17 ++++--
> 13 files changed, 168 insertions(+), 83 deletions(-)
> create mode 100644 include/linux/vfio_mdev.h
>
> diff --git a/Documentation/driver-api/vfio-mediated-device.rst b/Documentation/driver-api/vfio-mediated-device.rst
> index a5bdc60d62a1..d50425b368bb 100644
> --- a/Documentation/driver-api/vfio-mediated-device.rst
> +++ b/Documentation/driver-api/vfio-mediated-device.rst
> @@ -152,7 +152,9 @@ callbacks per mdev parent device, per mdev type, or any other categorization.
> Vendor drivers are expected to be fully asynchronous in this respect or
> provide their own internal resource protection.)
>
> -The callbacks in the mdev_parent_ops structure are as follows:
> +The device specific callbacks are referred through device_ops pointer
> +in mdev_parent_ops. For vfio-mdev device, its callbacks in device_ops
> +are as follows:
This is not accurate. device_ops is now on the mdev_device and is an
mdev bus driver specific structure of callbacks that must be registered
for each mdev device by the parent driver during the create callback.
There's a one to one mapping of class_id to mdev_device_ops callbacks.
That also suggests to me that we could be more clever in registering
both of these with mdev-core. Can we embed the class_id in the ops
structure in a common way so that the core can extract it and the bus
drivers can access their specific callbacks?
> * open: open callback of mediated device
> * close: close callback of mediated device
> diff --git a/MAINTAINERS b/MAINTAINERS
> index b2326dece28e..89832b316500 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17075,6 +17075,7 @@ S: Maintained
> F: Documentation/driver-api/vfio-mediated-device.rst
> F: drivers/vfio/mdev/
> F: include/linux/mdev.h
> +F: include/linux/vfio_mdev.h
> F: samples/vfio-mdev/
>
> VFIO PLATFORM DRIVER
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index f793252a3d2a..b274f5ee481f 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -42,6 +42,7 @@
> #include <linux/kvm_host.h>
> #include <linux/vfio.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> #include <linux/debugfs.h>
>
> #include <linux/nospec.h>
> @@ -643,6 +644,8 @@ static void kvmgt_put_vfio_device(void *vgpu)
> vfio_device_put(((struct intel_vgpu *)vgpu)->vdev.vfio_device);
> }
>
> +static struct vfio_mdev_device_ops intel_vfio_vgpu_dev_ops;
> +
> static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> struct intel_vgpu *vgpu = NULL;
> @@ -679,6 +682,7 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
> ret = 0;
>
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &intel_vfio_vgpu_dev_ops);
This seems rather unrefined. We're registering interdependent data in
separate calls. All drivers need to make both of these calls. I'm not
sure if this is a good idea, but what if we had:
static const struct vfio_mdev_device_ops intel_vfio_vgpu_dev_ops = {
.id = MDEV_ID_VFIO,
.open = intel_vgpu_open,
.release = intel_vgpu_release,
...
And the set function passed &intel_vfio_vgpu_dev_ops.id and the mdev
bus drivers used container_of to get to their callbacks?
> out:
> return ret;
> }
> @@ -1601,20 +1605,21 @@ static const struct attribute_group *intel_vgpu_groups[] = {
> NULL,
> };
>
> -static struct mdev_parent_ops intel_vgpu_ops = {
> - .mdev_attr_groups = intel_vgpu_groups,
> - .create = intel_vgpu_create,
> - .remove = intel_vgpu_remove,
> -
> +static struct vfio_mdev_device_ops intel_vfio_vgpu_dev_ops = {
> .open = intel_vgpu_open,
> .release = intel_vgpu_release,
> -
> .read = intel_vgpu_read,
> .write = intel_vgpu_write,
> .mmap = intel_vgpu_mmap,
> .ioctl = intel_vgpu_ioctl,
> };
>
> +static struct mdev_parent_ops intel_vgpu_ops = {
These could maybe be made const at the same time. Thanks,
Alex
> + .mdev_attr_groups = intel_vgpu_groups,
> + .create = intel_vgpu_create,
> + .remove = intel_vgpu_remove,
> +};
> +
> static int kvmgt_host_init(struct device *dev, void *gvt, const void *ops)
> {
> struct attribute **kvm_type_attrs;
> diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
> index d258ef1fedb9..329d53c1f46b 100644
> --- a/drivers/s390/cio/vfio_ccw_ops.c
> +++ b/drivers/s390/cio/vfio_ccw_ops.c
> @@ -12,6 +12,7 @@
>
> #include <linux/vfio.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> #include <linux/nospec.h>
> #include <linux/slab.h>
>
> @@ -110,6 +111,8 @@ static struct attribute_group *mdev_type_groups[] = {
> NULL,
> };
>
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
> static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> struct vfio_ccw_private *private =
> @@ -130,6 +133,7 @@ static int vfio_ccw_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
> private->sch->schid.sch_no);
>
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &vfio_mdev_ops);
> return 0;
> }
>
> @@ -575,11 +579,7 @@ static ssize_t vfio_ccw_mdev_ioctl(struct mdev_device *mdev,
> }
> }
>
> -static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> - .owner = THIS_MODULE,
> - .supported_type_groups = mdev_type_groups,
> - .create = vfio_ccw_mdev_create,
> - .remove = vfio_ccw_mdev_remove,
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
> .open = vfio_ccw_mdev_open,
> .release = vfio_ccw_mdev_release,
> .read = vfio_ccw_mdev_read,
> @@ -587,6 +587,13 @@ static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> .ioctl = vfio_ccw_mdev_ioctl,
> };
>
> +static const struct mdev_parent_ops vfio_ccw_mdev_ops = {
> + .owner = THIS_MODULE,
> + .supported_type_groups = mdev_type_groups,
> + .create = vfio_ccw_mdev_create,
> + .remove = vfio_ccw_mdev_remove,
> +};
> +
> int vfio_ccw_mdev_reg(struct subchannel *sch)
> {
> return mdev_register_device(&sch->dev, &vfio_ccw_mdev_ops);
> diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
> index 2cfd96112aa0..3a89933f0d3e 100644
> --- a/drivers/s390/crypto/vfio_ap_ops.c
> +++ b/drivers/s390/crypto/vfio_ap_ops.c
> @@ -16,6 +16,7 @@
> #include <linux/bitops.h>
> #include <linux/kvm_host.h>
> #include <linux/module.h>
> +#include <linux/vfio_mdev.h>
> #include <asm/kvm.h>
> #include <asm/zcrypt.h>
>
> @@ -321,6 +322,8 @@ static void vfio_ap_matrix_init(struct ap_config_info *info,
> matrix->adm_max = info->apxa ? info->Nd : 15;
> }
>
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
> static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> struct ap_matrix_mdev *matrix_mdev;
> @@ -344,6 +347,7 @@ static int vfio_ap_mdev_create(struct kobject *kobj, struct mdev_device *mdev)
> mutex_unlock(&matrix_dev->lock);
>
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &vfio_mdev_ops);
> return 0;
> }
>
> @@ -1281,15 +1285,18 @@ static ssize_t vfio_ap_mdev_ioctl(struct mdev_device *mdev,
> return ret;
> }
>
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
> + .open = vfio_ap_mdev_open,
> + .release = vfio_ap_mdev_release,
> + .ioctl = vfio_ap_mdev_ioctl,
> +};
> +
> static const struct mdev_parent_ops vfio_ap_matrix_ops = {
> .owner = THIS_MODULE,
> .supported_type_groups = vfio_ap_mdev_type_groups,
> .mdev_attr_groups = vfio_ap_mdev_attr_groups,
> .create = vfio_ap_mdev_create,
> .remove = vfio_ap_mdev_remove,
> - .open = vfio_ap_mdev_open,
> - .release = vfio_ap_mdev_release,
> - .ioctl = vfio_ap_mdev_ioctl,
> };
>
> int vfio_ap_mdev_register(void)
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index 8764cf4a276d..6f35f2ced2c9 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -51,6 +51,18 @@ void mdev_set_class_id(struct mdev_device *mdev, u16 id)
> }
> EXPORT_SYMBOL(mdev_set_class_id);
>
> +const void *mdev_get_dev_ops(struct mdev_device *mdev)
> +{
> + return mdev->device_ops;
> +}
> +EXPORT_SYMBOL(mdev_get_dev_ops);
> +
> +void mdev_set_dev_ops(struct mdev_device *mdev, const void *ops)
> +{
> + mdev->device_ops = ops;
> +}
> +EXPORT_SYMBOL(mdev_set_dev_ops);
> +
> struct device *mdev_dev(struct mdev_device *mdev)
> {
> return &mdev->dev;
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index c65f436c1869..b666805f0b1f 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -34,6 +34,7 @@ struct mdev_device {
> struct device *iommu_device;
> bool active;
> u16 class_id;
> + const void *device_ops;
> };
>
> #define to_mdev_device(dev) container_of(dev, struct mdev_device, dev)
> diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
> index 891cf83a2d9a..95efa054442f 100644
> --- a/drivers/vfio/mdev/vfio_mdev.c
> +++ b/drivers/vfio/mdev/vfio_mdev.c
> @@ -14,6 +14,7 @@
> #include <linux/slab.h>
> #include <linux/vfio.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
>
> #include "mdev_private.h"
>
> @@ -24,16 +25,16 @@
> static int vfio_mdev_open(void *device_data)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
> int ret;
>
> - if (unlikely(!parent->ops->open))
> + if (unlikely(!ops->open))
> return -EINVAL;
>
> if (!try_module_get(THIS_MODULE))
> return -ENODEV;
>
> - ret = parent->ops->open(mdev);
> + ret = ops->open(mdev);
> if (ret)
> module_put(THIS_MODULE);
>
> @@ -43,10 +44,10 @@ static int vfio_mdev_open(void *device_data)
> static void vfio_mdev_release(void *device_data)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
>
> - if (likely(parent->ops->release))
> - parent->ops->release(mdev);
> + if (likely(ops->release))
> + ops->release(mdev);
>
> module_put(THIS_MODULE);
> }
> @@ -55,47 +56,47 @@ static long vfio_mdev_unlocked_ioctl(void *device_data,
> unsigned int cmd, unsigned long arg)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
>
> - if (unlikely(!parent->ops->ioctl))
> + if (unlikely(!ops->ioctl))
> return -EINVAL;
>
> - return parent->ops->ioctl(mdev, cmd, arg);
> + return ops->ioctl(mdev, cmd, arg);
> }
>
> static ssize_t vfio_mdev_read(void *device_data, char __user *buf,
> size_t count, loff_t *ppos)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
>
> - if (unlikely(!parent->ops->read))
> + if (unlikely(!ops->read))
> return -EINVAL;
>
> - return parent->ops->read(mdev, buf, count, ppos);
> + return ops->read(mdev, buf, count, ppos);
> }
>
> static ssize_t vfio_mdev_write(void *device_data, const char __user *buf,
> size_t count, loff_t *ppos)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
>
> - if (unlikely(!parent->ops->write))
> + if (unlikely(!ops->write))
> return -EINVAL;
>
> - return parent->ops->write(mdev, buf, count, ppos);
> + return ops->write(mdev, buf, count, ppos);
> }
>
> static int vfio_mdev_mmap(void *device_data, struct vm_area_struct *vma)
> {
> struct mdev_device *mdev = device_data;
> - struct mdev_parent *parent = mdev->parent;
> + const struct vfio_mdev_device_ops *ops = mdev_get_dev_ops(mdev);
>
> - if (unlikely(!parent->ops->mmap))
> + if (unlikely(!ops->mmap))
> return -EINVAL;
>
> - return parent->ops->mmap(mdev, vma);
> + return ops->mmap(mdev, vma);
> }
>
> static const struct vfio_device_ops vfio_mdev_dev_ops = {
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index 3974650c074f..3414307311f1 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -10,6 +10,11 @@
> #ifndef MDEV_H
> #define MDEV_H
>
> +#include <linux/types.h>
> +#include <linux/device.h>
> +#include <linux/mdev.h>
> +#include <uapi/linux/uuid.h>
> +
> struct mdev_device;
>
> /*
> @@ -48,30 +53,8 @@ struct device *mdev_get_iommu_device(struct device *dev);
> * @mdev: mdev_device device structure which is being
> * destroyed
> * Returns integer: success (0) or error (< 0)
> - * @open: Open mediated device.
> - * @mdev: mediated device.
> - * Returns integer: success (0) or error (< 0)
> - * @release: release mediated device
> - * @mdev: mediated device.
> - * @read: Read emulation callback
> - * @mdev: mediated device structure
> - * @buf: read buffer
> - * @count: number of bytes to read
> - * @ppos: address.
> - * Retuns number on bytes read on success or error.
> - * @write: Write emulation callback
> - * @mdev: mediated device structure
> - * @buf: write buffer
> - * @count: number of bytes to be written
> - * @ppos: address.
> - * Retuns number on bytes written on success or error.
> - * @ioctl: IOCTL callback
> - * @mdev: mediated device structure
> - * @cmd: ioctl command
> - * @arg: arguments to ioctl
> - * @mmap: mmap callback
> - * @mdev: mediated device structure
> - * @vma: vma structure
> + * @device_ops: Device specific emulation callback.
> + *
> * Parent device that support mediated device should be registered with mdev
> * module with mdev_parent_ops structure.
> **/
> @@ -83,15 +66,6 @@ struct mdev_parent_ops {
>
> int (*create)(struct kobject *kobj, struct mdev_device *mdev);
> int (*remove)(struct mdev_device *mdev);
> - int (*open)(struct mdev_device *mdev);
> - void (*release)(struct mdev_device *mdev);
> - ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
> - size_t count, loff_t *ppos);
> - ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
> - size_t count, loff_t *ppos);
> - long (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
> - unsigned long arg);
> - int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
> };
>
> /* interface for exporting mdev supported type attributes */
> @@ -133,6 +107,8 @@ struct mdev_driver {
>
> void *mdev_get_drvdata(struct mdev_device *mdev);
> void mdev_set_drvdata(struct mdev_device *mdev, void *data);
> +const void *mdev_get_dev_ops(struct mdev_device *mdev);
> +void mdev_set_dev_ops(struct mdev_device *mdev, const void *ops);
> void mdev_set_class_id(struct mdev_device *mdev, u16 id);
> const guid_t *mdev_uuid(struct mdev_device *mdev);
>
> diff --git a/include/linux/vfio_mdev.h b/include/linux/vfio_mdev.h
> new file mode 100644
> index 000000000000..3907c5371c2b
> --- /dev/null
> +++ b/include/linux/vfio_mdev.h
> @@ -0,0 +1,52 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * VFIO Mediated device definition
> + */
> +
> +#ifndef VFIO_MDEV_H
> +#define VFIO_MDEV_H
> +
> +#include <linux/mdev.h>
> +
> +/**
> + * struct vfio_mdev_device_ops - Structure to be registered for each
> + * mdev device to register the device to vfio-mdev module.
> + *
> + * @open: Open mediated device.
> + * @mdev: mediated device.
> + * Returns integer: success (0) or error (< 0)
> + * @release: release mediated device
> + * @mdev: mediated device.
> + * @read: Read emulation callback
> + * @mdev: mediated device structure
> + * @buf: read buffer
> + * @count: number of bytes to read
> + * @ppos: address.
> + * Retuns number on bytes read on success or error.
> + * @write: Write emulation callback
> + * @mdev: mediated device structure
> + * @buf: write buffer
> + * @count: number of bytes to be written
> + * @ppos: address.
> + * Retuns number on bytes written on success or error.
> + * @ioctl: IOCTL callback
> + * @mdev: mediated device structure
> + * @cmd: ioctl command
> + * @arg: arguments to ioctl
> + * @mmap: mmap callback
> + * @mdev: mediated device structure
> + * @vma: vma structure
> + */
> +struct vfio_mdev_device_ops {
> + int (*open)(struct mdev_device *mdev);
> + void (*release)(struct mdev_device *mdev);
> + ssize_t (*read)(struct mdev_device *mdev, char __user *buf,
> + size_t count, loff_t *ppos);
> + ssize_t (*write)(struct mdev_device *mdev, const char __user *buf,
> + size_t count, loff_t *ppos);
> + long (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
> + unsigned long arg);
> + int (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
> +};
> +
> +#endif
> diff --git a/samples/vfio-mdev/mbochs.c b/samples/vfio-mdev/mbochs.c
> index 8a8583c892b2..b4bf29c6136c 100644
> --- a/samples/vfio-mdev/mbochs.c
> +++ b/samples/vfio-mdev/mbochs.c
> @@ -30,6 +30,7 @@
> #include <linux/iommu.h>
> #include <linux/sysfs.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> #include <linux/pci.h>
> #include <linux/dma-buf.h>
> #include <linux/highmem.h>
> @@ -516,6 +517,8 @@ static int mbochs_reset(struct mdev_device *mdev)
> return 0;
> }
>
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
> static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> const struct mbochs_type *type = mbochs_find_type(kobj);
> @@ -562,6 +565,7 @@ static int mbochs_create(struct kobject *kobj, struct mdev_device *mdev)
>
> mbochs_used_mbytes += type->mbytes;
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &vfio_mdev_ops);
> return 0;
>
> err_mem:
> @@ -1419,12 +1423,7 @@ static struct attribute_group *mdev_type_groups[] = {
> NULL,
> };
>
> -static const struct mdev_parent_ops mdev_fops = {
> - .owner = THIS_MODULE,
> - .mdev_attr_groups = mdev_dev_groups,
> - .supported_type_groups = mdev_type_groups,
> - .create = mbochs_create,
> - .remove = mbochs_remove,
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
> .open = mbochs_open,
> .release = mbochs_close,
> .read = mbochs_read,
> @@ -1433,6 +1432,14 @@ static const struct mdev_parent_ops mdev_fops = {
> .mmap = mbochs_mmap,
> };
>
> +static const struct mdev_parent_ops mdev_fops = {
> + .owner = THIS_MODULE,
> + .mdev_attr_groups = mdev_dev_groups,
> + .supported_type_groups = mdev_type_groups,
> + .create = mbochs_create,
> + .remove = mbochs_remove,
> +};
> +
> static const struct file_operations vd_fops = {
> .owner = THIS_MODULE,
> };
> diff --git a/samples/vfio-mdev/mdpy.c b/samples/vfio-mdev/mdpy.c
> index 88d7e76f3836..80c2df531326 100644
> --- a/samples/vfio-mdev/mdpy.c
> +++ b/samples/vfio-mdev/mdpy.c
> @@ -26,6 +26,7 @@
> #include <linux/iommu.h>
> #include <linux/sysfs.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> #include <linux/pci.h>
> #include <drm/drm_fourcc.h>
> #include "mdpy-defs.h"
> @@ -226,6 +227,8 @@ static int mdpy_reset(struct mdev_device *mdev)
> return 0;
> }
>
> +static const struct vfio_mdev_device_ops vfio_mdev_ops;
> +
> static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> const struct mdpy_type *type = mdpy_find_type(kobj);
> @@ -270,6 +273,7 @@ static int mdpy_create(struct kobject *kobj, struct mdev_device *mdev)
>
> mdpy_count++;
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &vfio_mdev_ops);
> return 0;
> }
>
> @@ -726,12 +730,7 @@ static struct attribute_group *mdev_type_groups[] = {
> NULL,
> };
>
> -static const struct mdev_parent_ops mdev_fops = {
> - .owner = THIS_MODULE,
> - .mdev_attr_groups = mdev_dev_groups,
> - .supported_type_groups = mdev_type_groups,
> - .create = mdpy_create,
> - .remove = mdpy_remove,
> +static const struct vfio_mdev_device_ops vfio_mdev_ops = {
> .open = mdpy_open,
> .release = mdpy_close,
> .read = mdpy_read,
> @@ -740,6 +739,14 @@ static const struct mdev_parent_ops mdev_fops = {
> .mmap = mdpy_mmap,
> };
>
> +static const struct mdev_parent_ops mdev_fops = {
> + .owner = THIS_MODULE,
> + .mdev_attr_groups = mdev_dev_groups,
> + .supported_type_groups = mdev_type_groups,
> + .create = mdpy_create,
> + .remove = mdpy_remove,
> +};
> +
> static const struct file_operations vd_fops = {
> .owner = THIS_MODULE,
> };
> diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
> index 4e0735143b69..2db860ccb02c 100644
> --- a/samples/vfio-mdev/mtty.c
> +++ b/samples/vfio-mdev/mtty.c
> @@ -27,6 +27,7 @@
> #include <linux/ctype.h>
> #include <linux/file.h>
> #include <linux/mdev.h>
> +#include <linux/vfio_mdev.h>
> #include <linux/pci.h>
> #include <linux/serial.h>
> #include <uapi/linux/serial_reg.h>
> @@ -723,6 +724,8 @@ static ssize_t mdev_access(struct mdev_device *mdev, u8 *buf, size_t count,
> return ret;
> }
>
> +static const struct vfio_mdev_device_ops vfio_dev_ops;
> +
> static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
> {
> struct mdev_state *mdev_state;
> @@ -771,6 +774,7 @@ static int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
> mutex_unlock(&mdev_list_lock);
>
> mdev_set_class_id(mdev, MDEV_ID_VFIO);
> + mdev_set_dev_ops(mdev, &vfio_dev_ops);
> return 0;
> }
>
> @@ -1411,6 +1415,14 @@ static struct attribute_group *mdev_type_groups[] = {
> NULL,
> };
>
> +static const struct vfio_mdev_device_ops vfio_dev_ops = {
> + .open = mtty_open,
> + .release = mtty_close,
> + .read = mtty_read,
> + .write = mtty_write,
> + .ioctl = mtty_ioctl,
> +};
> +
> static const struct mdev_parent_ops mdev_fops = {
> .owner = THIS_MODULE,
> .dev_attr_groups = mtty_dev_groups,
> @@ -1418,11 +1430,6 @@ static const struct mdev_parent_ops mdev_fops = {
> .supported_type_groups = mdev_type_groups,
> .create = mtty_create,
> .remove = mtty_remove,
> - .open = mtty_open,
> - .release = mtty_close,
> - .read = mtty_read,
> - .write = mtty_write,
> - .ioctl = mtty_ioctl,
> };
>
> static void mtty_device_release(struct device *dev)
