[PATCH v1 0/7] vfio-ccw parent rework

Eric Farman
2022-10-19T16:22:04Z

Hi all,

There have been discussions and attempts [1][2] to rework the vfio-ccw device
lifecycle to better align with the needs/expectations of vfio and mdev.
While those languished, commit cb9ff3f3b84c ("vfio: Add helpers for unifying
vfio_device life cycle") implemented a couple of tricks that help vfio and the
drivers that interact with it, while keeping vfio-ccw as-is. A handful of
commits titled "vfio/xxx: Use the new device life cycle helpers" implemented
those tricks for each of the drivers.

This series attempts to address the oddities/shortcomings of vfio-ccw, such
that vfio-ccw can use the same helpers as everyone else, and the tricks that
were implemented by the other drivers can be removed. It is built on 6.1-rc1,
and thus includes the various changes [3][4] that have occurred in and around
these parts.

Patches 1-5 rework the behavior of the vfio-ccw driver's private struct.
In summary, the mdev pieces are split out of vfio_ccw_private and into a
new vfio_ccw_parent struct that will continue to follow today's lifecycle.
The remainder (bulk) of the private struct moves to follow the mdev
probe/remove pair. There's opportunity for further separation of the
things in the private struct, which would simplify some of the vfio-ccw
code, but it got too hairy as I started that. Once vfio-ccw is no longer
considered unique, those cleanups can happen at our leisure.

Patch 6 removes the trickery where vfio-ccw uses vfio_init_device instead of
vfio_alloc_device, and thus removes vfio_init_device from the outside world.

Patch 7 removes vfio_free_device from vfio-ccw and the other drivers (hello,
CC list!), letting it be handled by vfio_device_release directly.

Looking forward to the feedback.

Thanks,
Eric

[1] https://lore.kernel.org/kvm/0-v3-57c1502c62fd+2190-ccw_mdev_jgg@nvidia.com/
[2] https://lore.kernel.org/kvm/20220602171948.2790690-1-farman@linux.ibm.com/
[3] https://lore.kernel.org/kvm/20220923092652.100656-1-hch@lst.de/
[4] https://lore.kernel.org/kvm/20220921104401.38898-1-kevin.tian@intel.com/

Eric Farman (7):
vfio/ccw: create a parent struct
vfio/ccw: remove private->sch
vfio/ccw: move private initialization to callback
vfio/ccw: move private to mdev lifecycle
vfio/ccw: remove release completion
vfio/ccw: replace vfio_init_device with _alloc_
vfio: Remove vfio_free_device

drivers/gpu/drm/i915/gvt/kvmgt.c | 1 -
drivers/s390/cio/vfio_ccw_chp.c | 5 +-
drivers/s390/cio/vfio_ccw_drv.c | 182 ++++++++++----------------
drivers/s390/cio/vfio_ccw_fsm.c | 27 ++--
drivers/s390/cio/vfio_ccw_ops.c | 108 ++++++++++-----
drivers/s390/cio/vfio_ccw_parent.h | 28 ++++
drivers/s390/cio/vfio_ccw_private.h | 22 ++--
drivers/s390/crypto/vfio_ap_ops.c | 6 -
drivers/vfio/fsl-mc/vfio_fsl_mc.c | 1 -
drivers/vfio/pci/vfio_pci_core.c | 1 -
drivers/vfio/platform/vfio_amba.c | 1 -
drivers/vfio/platform/vfio_platform.c | 1 -
drivers/vfio/vfio_main.c | 25 +---
include/linux/vfio.h | 1 -
samples/vfio-mdev/mbochs.c | 1 -
samples/vfio-mdev/mdpy.c | 1 -
samples/vfio-mdev/mtty.c | 1 -
17 files changed, 204 insertions(+), 208 deletions(-)
create mode 100644 drivers/s390/cio/vfio_ccw_parent.h

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2.34.1