Re: [PATCH v2 00/18] Make vfio_mdev type safe

[Alex Williamson <alex.williamson@redhat.com>]

On Tue,  6 Apr 2021 16:40:23 -0300
Jason Gunthorpe <jgg@nvidia.com> wrote:

> vfio_mdev has a number of different objects: mdev_parent, mdev_type and
> mdev_device.
> 
> Unfortunately the types of these have been erased in various places
> throughout the API, and this makes it very hard to understand this code or
> maintain it by the time it reaches all of the drivers.
> 
> This series puts in all the types and aligns some of the design with the
> driver core standard for a driver core bus driver:
> 
>  - Replace 'struct device *' with 'struct mdev_device *
>  - Replace 'struct device *' with 'struct mdev_type *' and
>    mtype_get_parent_dev()
>  - Replace 'struct kobject *' with 'struct mdev_type *'
> 
> Now that types are clear it is easy to spot a few places that have
> duplicated information.
> 
> More significantly we can now understand how to directly fix the
> obfuscated 'kobj->name' matching by realizing the the kobj is a mdev_type,
> which is linked to the supported_types_list provided by the driver, and
> thus the core code can directly return the array indexes all the drivers
> actually want.
> 
> v2:
>  - Use a mdev_type local in mdev_create_sysfs_files
>  - Rename the goto unwind labels in mdev_device_free()
>  - Reorder patches, annotate reviewed-by's thanks all
> v1: https://lore.kernel.org/r/0-v1-7dedf20b2b75+4f785-vfio2_jgg@nvidia.com
> 
> Jason Gunthorpe (18):
>   vfio/mdev: Fix missing static's on MDEV_TYPE_ATTR's
>   vfio/mdev: Do not allow a mdev_type to have a NULL parent pointer
>   vfio/mdev: Add missing typesafety around mdev_device
>   vfio/mdev: Simplify driver registration
>   vfio/mdev: Use struct mdev_type in struct mdev_device
>   vfio/mdev: Expose mdev_get/put_parent to mdev_private.h
>   vfio/mdev: Add missing reference counting to mdev_type
>   vfio/mdev: Reorganize mdev_device_create()
>   vfio/mdev: Add missing error handling to dev_set_name()
>   vfio/mdev: Remove duplicate storage of parent in mdev_device
>   vfio/mdev: Add mdev/mtype_get_type_group_id()
>   vfio/mtty: Use mdev_get_type_group_id()
>   vfio/mdpy: Use mdev_get_type_group_id()
>   vfio/mbochs: Use mdev_get_type_group_id()
>   vfio/gvt: Make DRM_I915_GVT depend on VFIO_MDEV
>   vfio/gvt: Use mdev_get_type_group_id()
>   vfio/mdev: Remove kobj from mdev_parent_ops->create()
>   vfio/mdev: Correct the function signatures for the
>     mdev_type_attributes
> 
>  .../driver-api/vfio-mediated-device.rst       |   9 +-
>  drivers/gpu/drm/i915/Kconfig                  |   1 +
>  drivers/gpu/drm/i915/gvt/gvt.c                |  41 ++---
>  drivers/gpu/drm/i915/gvt/gvt.h                |   4 +-
>  drivers/gpu/drm/i915/gvt/kvmgt.c              |   7 +-
>  drivers/s390/cio/vfio_ccw_ops.c               |  17 +-
>  drivers/s390/crypto/vfio_ap_ops.c             |  14 +-
>  drivers/vfio/mdev/mdev_core.c                 | 174 +++++++-----------
>  drivers/vfio/mdev/mdev_driver.c               |  19 +-
>  drivers/vfio/mdev/mdev_private.h              |  40 ++--
>  drivers/vfio/mdev/mdev_sysfs.c                |  59 +++---
>  drivers/vfio/mdev/vfio_mdev.c                 |  29 +--
>  drivers/vfio/vfio_iommu_type1.c               |  25 +--
>  include/linux/mdev.h                          |  80 +++++---
>  samples/vfio-mdev/mbochs.c                    |  55 +++---
>  samples/vfio-mdev/mdpy.c                      |  56 +++---
>  samples/vfio-mdev/mtty.c                      |  66 ++-----
>  17 files changed, 313 insertions(+), 383 deletions(-)

Applied to vfio next branch for v5.13.  Thanks!

Alex