[PATCH v2 0/9] Move vfio_ccw to the new mdev API

[Jason Gunthorpe]

This addresses Cornelia's remark on the earlier patch that ccw has a
confusing lifecycle. While it doesn't seem like the original attempt was
functionally wrong, the result can be made better with a lot of further
work.

Reorganize the driver so that the mdev owns the private memory and
controls the lifecycle, not the css_driver. The memory associated with the
css_driver lifecycle is only the mdev_parent/mdev_type registration.

Along the way we change when the sch is quiescent or not to be linked to
the open/close_device lifetime of the vfio_device, which is sort of what
it was tring to do already, just not completely.

The troublesome racey lifecycle of the css_driver callbacks is made clear
with simple vfio_device refcounting so a callback is only delivered into a
registered vfio_device and has obvious correctness.

Move the only per-css_driver state, the "available instance" counter, into
the core code and share that logic with many of the other drivers. The
value is kept in the mdev_type memory.

v2:
 - Clean up the lifecycle in ccw with 7 new patches
 - Rebase
v1: https://lore.kernel.org/all/7-v2-7667f42c9bad+935-vfio3_jgg@nvidia.com

Jason Gunthorpe (9):
  vfio/ccw: Use functions for alloc/free of the vfio_ccw_private
  vfio/ccw: Pass vfio_ccw_private not mdev_device to various functions
  vfio/ccw: Convert to use vfio_register_group_dev()
  vfio/ccw: Make the FSM complete and synchronize it to the mdev
  vfio/mdev: Consolidate all the device_api sysfs into the core code
  vfio/mdev: Add mdev available instance checking to the core
  vfio/ccw: Remove private->mdev
  vfio: Export vfio_device_try_get()
  vfio/ccw: Move the lifecycle of the struct vfio_ccw_private to the
    mdev

 drivers/gpu/drm/i915/gvt/kvmgt.c      |   9 +-
 drivers/s390/cio/vfio_ccw_drv.c       | 282 +++++++++++---------------
 drivers/s390/cio/vfio_ccw_fsm.c       | 152 ++++++++++----
 drivers/s390/cio/vfio_ccw_ops.c       | 240 ++++++++++------------
 drivers/s390/cio/vfio_ccw_private.h   |  42 +++-
 drivers/s390/crypto/vfio_ap_ops.c     |  41 +---
 drivers/s390/crypto/vfio_ap_private.h |   2 -
 drivers/vfio/mdev/mdev_core.c         |  13 +-
 drivers/vfio/mdev/mdev_private.h      |   2 +
 drivers/vfio/mdev/mdev_sysfs.c        |  64 +++++-
 drivers/vfio/vfio.c                   |   3 +-
 include/linux/mdev.h                  |  13 +-
 include/linux/vfio.h                  |   1 +
 samples/vfio-mdev/mbochs.c            |   9 +-
 samples/vfio-mdev/mdpy.c              |  31 +--
 samples/vfio-mdev/mtty.c              |  10 +-
 16 files changed, 470 insertions(+), 444 deletions(-)

-- 
2.33.0