drm/vkms: Add configfs support

Hi everyone,

This series allow to configure one or more VKMS instances without having
to reload the driver using configfs.

The series is structured in 3 blocks:

  - Patches 1..11: Basic device configuration. For simplicity, I kept the
    available options as minimal as possible.

  - Patches 12 and 13: New option to skip the default device creation and to-do
    cleanup.

  - Patches 14, 15 and 16: Allow to hot-plug and unplug connectors. This is not
    part of the minimal set of options, but I included in this series so it can
    be used as a template/example of how new configurations can be added.

The process of configuring a VKMS device is documented in "vkms.rst".

Finally, the code is thoroughly tested by a collection of IGT tests [1].

Best wishes,
José Expósito

[1] https://lists.freedesktop.org/archives/igt-dev/2025-Febru...

Changes in v5:

  - Added Reviewed-by tags, thanks Louis!
  - Rebased on top of drm-misc-next
  - Link to v4: https://lore.kernel.org/dri-devel/20250407081425.6420-1-j...

Changes in v4:

  - Since Louis and I worked on this together, set him as the author of some of
    the patches and me as co-developed-by to reflect this joint effort.
  - Rebased on top of drm-misc-next
  - Link to v3: https://lore.kernel.org/all/20250307163353.5896-1-jose.ex...

Changes in v3:

  - Applied review comments by Louis Chauvet: (thanks!!)
    - Use scoped_guard() instead of guard(mutex)(...)
    - Fix a use-after-free error in the connector hot-plug code
  - Rebased on top of drm-misc-next
  - Link to v2: https://lore.kernel.org/all/20250225175936.7223-1-jose.ex...

Changes in v2:

  - Applied review comments by Louis Chauvet:
    - Use guard(mutex)(...) instead of lock/unlock
    - Return -EBUSY when trying to modify a enabled device
    - Move the connector hot-plug related patches to the end
  - Rebased on top of drm-misc-next
  - Link to v1: https://lore.kernel.org/dri-devel/20250218170808.9507-1-j...

José Expósito (6):
  drm/vkms: Expose device creation and destruction
  drm/vkms: Allow to configure the default device creation
  drm/vkms: Remove completed task from the TODO list
  drm/vkms: Allow to configure connector status
  drm/vkms: Allow to update the connector status
  drm/vkms: Allow to configure connector status via configfs

Louis Chauvet (10):
  drm/vkms: Add and remove VKMS instances via configfs
  drm/vkms: Allow to configure multiple planes via configfs
  drm/vkms: Allow to configure the plane type via configfs
  drm/vkms: Allow to configure multiple CRTCs via configfs
  drm/vkms: Allow to configure CRTC writeback support via configfs
  drm/vkms: Allow to attach planes and CRTCs via configfs
  drm/vkms: Allow to configure multiple encoders via configfs
  drm/vkms: Allow to attach encoders and CRTCs via configfs
  drm/vkms: Allow to configure multiple connectors via configfs
  drm/vkms: Allow to attach connectors and encoders via configfs

 Documentation/gpu/vkms.rst                    | 100 ++-
 drivers/gpu/drm/vkms/Kconfig                  |   1 +
 drivers/gpu/drm/vkms/Makefile                 |   3 +-
 drivers/gpu/drm/vkms/tests/vkms_config_test.c |  24 +
 drivers/gpu/drm/vkms/vkms_config.c            |   8 +-
 drivers/gpu/drm/vkms/vkms_config.h            |  26 +
 drivers/gpu/drm/vkms/vkms_configfs.c          | 833 ++++++++++++++++++
 drivers/gpu/drm/vkms/vkms_configfs.h          |   8 +
 drivers/gpu/drm/vkms/vkms_connector.c         |  35 +
 drivers/gpu/drm/vkms/vkms_connector.h         |   9 +
 drivers/gpu/drm/vkms/vkms_drv.c               |  18 +-
 drivers/gpu/drm/vkms/vkms_drv.h               |  20 +
 12 files changed, 1072 insertions(+), 13 deletions(-)
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.c
 create mode 100644 drivers/gpu/drm/vkms/vkms_configfs.h


base-commit: a6c0a91ccb257eaec2aee080df06863ce7601315
-- 
2.49.0