[PATCH V2 5/8] mdev: introduce device specific ops

Rob Miller rob.miller at broadcom.com
Wed Sep 25 14:11:00 UTC 2019


On Wed, Sep 25, 2019 at 4:52 AM Tian, Kevin <kevin.tian at intel.com> wrote:

> > From: Alex Williamson
> > Sent: Wednesday, September 25, 2019 7:07 AM
> >
> > On Tue, 24 Sep 2019 21:53:29 +0800
> > Jason Wang <jasowang at redhat.com> 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 at redhat.com>
> > > ---
> > >  .../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.
>
> there is also a mistake in include/Linux/mdev.h, where device_ops is
> still part of mdev_parent_ops in the comment line.
>
> >
> > 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?
>
> or just make it explicit? e.g.
>
> mdev_set_class(mdev, MDEV_ID_VFIO, &intel_vfio_vgpu_dev_ops);
>
> >
> > >  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;
>

RJM>] My understanding lately is that this call to
try_module_get(THIS_MODULE) is no longer needed as is considered as a
latent bug.
Quote from
https://stackoverflow.com/questions/1741415/linux-kernel-modules-when-to-use-try-module-get-module-put
 :
There are a number of uses of try_module_get(THIS_MODULE) in the kernel
source but most if not all of them are latent bugs that should be cleaned
up.

> >
> > > -   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)
> >
> > _______________________________________________
> > intel-gvt-dev mailing list
> > intel-gvt-dev at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev
>
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