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

Jason Gunthorpe
2021-09-09T19:39:25Z

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