linux/include
Kevin Tian cb9ff3f3b8 vfio: Add helpers for unifying vfio_device life cycle
The idea is to let vfio core manage the vfio_device life cycle instead
of duplicating the logic cross drivers. This is also a preparatory
step for adding struct device into vfio_device.

New pair of helpers together with a kref in vfio_device:

 - vfio_alloc_device()
 - vfio_put_device()

Drivers can register @init/@release callbacks to manage any private
state wrapping the vfio_device.

However vfio-ccw doesn't fit this model due to a life cycle mess
that its private structure mixes both parent and mdev info hence must
be allocated/freed outside of the life cycle of vfio device.

Per prior discussions this won't be fixed in short term by IBM folks.

Instead of waiting for those modifications introduce another helper
vfio_init_device() so ccw can call it to initialize a pre-allocated
vfio_device.

Further implication of the ccw trick is that vfio_device cannot be
freed uniformly in vfio core. Instead, require *EVERY* driver to
implement @release and free vfio_device inside. Then ccw can choose
to delay the free at its own discretion.

Another trick down the road is that kvzalloc() is used to accommodate
the need of gvt which uses vzalloc() while all others use kzalloc().
So drivers should call a helper vfio_free_device() to free the
vfio_device instead of assuming that kfree() or vfree() is appliable.

Later once the ccw mess is fixed we can remove those tricks and
fully handle structure alloc/free in vfio core.

Existing vfio_{un}init_group_dev() will be deprecated after all
existing usages are converted to the new model.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Co-developed-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Link: https://lore.kernel.org/r/20220921104401.38898-2-kevin.tian@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2022-09-21 14:15:10 -06:00
..
acpi Merge branch 'acpi-properties' 2022-08-11 19:21:03 +02:00
asm-generic Seventeen hotfixes. Mostly memory management things. Ten patches are 2022-08-28 14:49:59 -07:00
clocksource
crypto for-5.20/block-2022-08-04 2022-08-04 20:00:14 -07:00
drm
dt-bindings power supply and reset changes for the v6.0 series 2022-08-12 09:37:33 -07:00
keys
kunit
kvm
linux vfio: Add helpers for unifying vfio_device life cycle 2022-09-21 14:15:10 -06:00
math-emu
media SPDX changes for 6.0-rc1 2022-08-04 12:12:54 -07:00
memory
misc
net tcp: make global challenge ack rate limitation per net-ns and default disabled 2022-08-31 19:56:48 -07:00
pcmcia
ras mm, hwpoison: enable memory error handling on 1GB hugepage 2022-08-08 18:06:44 -07:00
rdma dma-mapping updates 2022-08-06 10:56:45 -07:00
rv Documentation/rv: Add deterministic automata monitor synthesis documentation 2022-07-30 14:01:29 -04:00
scsi SCSI misc on 20220813 2022-08-13 13:41:48 -07:00
soc net: mscc: ocelot: keep ocelot_stat_layout by reg address, not offset 2022-08-17 21:58:32 -07:00
sound ASoC: More updates for v5.20 2022-08-01 15:26:40 +02:00
target scsi: target: core: De-RCU of se_lun and se_lun acl 2022-08-01 19:36:02 -04:00
trace * Xen timer fixes 2022-08-11 12:10:08 -07:00
uapi vfio: Introduce DMA logging uAPIs 2022-09-08 12:59:00 -06:00
ufs scsi: ufs: core: Enable link lost interrupt 2022-08-11 22:04:32 -04:00
vdso
video
xen x86/xen: Add support for HVMOP_set_evtchn_upcall_vector 2022-08-12 11:28:21 +02:00