vfio/mdev: Move the compat_class initialization to module init

The pointer to mdev_bus_compat_class is statically defined at the top
of mdev_core, and was originally (commit 7b96953bc640 ("vfio: Med

vfio/mdev: Move the compat_class initialization to module init

The pointer to mdev_bus_compat_class is statically defined at the top
of mdev_core, and was originally (commit 7b96953bc640 ("vfio: Mediated
device Core driver") serialized by the parent_list_lock. The blamed
commit removed this mutex, leaving the pointer initialization
unserialized. As a result, the creation of multiple MDEVs in parallel
(such as during boot) can encounter errors during the creation of the
sysfs entries, such as:

[ 8.337509] sysfs: cannot create duplicate filename '/class/mdev_bus'
[ 8.337514] vfio_ccw 0.0.01d8: MDEV: Registered
[ 8.337516] CPU: 13 PID: 946 Comm: driverctl Not tainted 6.4.0-rc7 #20
[ 8.337522] Hardware name: IBM 3906 M05 780 (LPAR)
[ 8.337525] Call Trace:
[ 8.337528] [<0000000162b0145a>] dump_stack_lvl+0x62/0x80
[ 8.337540] [<00000001622aeb30>] sysfs_warn_dup+0x78/0x88
[ 8.337549] [<00000001622aeca6>] sysfs_create_dir_ns+0xe6/0xf8
[ 8.337552] [<0000000162b04504>] kobject_add_internal+0xf4/0x340
[ 8.337557] [<0000000162b04d48>] kobject_add+0x78/0xd0
[ 8.337561] [<0000000162b04e0a>] kobject_create_and_add+0x6a/0xb8
[ 8.337565] [<00000001627a110e>] class_compat_register+0x5e/0x90
[ 8.337572] [<000003ff7fd815da>] mdev_register_parent+0x102/0x130 [mdev]
[ 8.337581] [<000003ff7fdc7f2c>] vfio_ccw_sch_probe+0xe4/0x178 [vfio_ccw]
[ 8.337588] [<0000000162a7833c>] css_probe+0x44/0x80
[ 8.337599] [<000000016279f4da>] really_probe+0xd2/0x460
[ 8.337603] [<000000016279fa08>] driver_probe_device+0x40/0xf0
[ 8.337606] [<000000016279fb78>] __device_attach_driver+0xc0/0x140
[ 8.337610] [<000000016279cbe0>] bus_for_each_drv+0x90/0xd8
[ 8.337618] [<00000001627a00b0>] __device_attach+0x110/0x190
[ 8.337621] [<000000016279c7c8>] bus_rescan_devices_helper+0x60/0xb0
[ 8.337626] [<000000016279cd48>] drivers_probe_store+0x48/0x80
[ 8.337632] [<00000001622ac9b0>] kernfs_fop_write_iter+0x138/0x1f0
[ 8.337635] [<00000001621e5e14>] vfs_write+0x1ac/0x2f8
[ 8.337645] [<00000001621e61d8>] ksys_write+0x70/0x100
[ 8.337650] [<0000000162b2bdc4>] __do_syscall+0x1d4/0x200
[ 8.337656] [<0000000162b3c828>] system_call+0x70/0x98
[ 8.337664] kobject: kobject_add_internal failed for mdev_bus with -EEXIST, don't try to register things with the same name in the same directory.
[ 8.337668] kobject: kobject_create_and_add: kobject_add error: -17
[ 8.337674] vfio_ccw: probe of 0.0.01d9 failed with error -12
[ 8.342941] vfio_ccw_mdev aeb9ca91-10c6-42bc-a168-320023570aea: Adding to iommu group 2

Move the initialization of the mdev_bus_compat_class pointer to the
init path, to match the cleanup in module exit. This way the code
in mdev_register_parent() can simply link the new parent to it,
rather than determining whether initialization is required first.

Fixes: 89345d5177aa ("vfio/mdev: embedd struct mdev_parent in the parent data structure")
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230626133642.2939168-1-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: add mdev available instance checking to the core

Many of the mdev drivers use a simple counter for keeping track of the
available instances. Move this code to the core code and store the

vfio/mdev: add mdev available instance checking to the core

Many of the mdev drivers use a simple counter for keeping track of the
available instances. Move this code to the core code and store the counter
in the mdev_parent. Implement it using correct locking, fixing mdpy.

Drivers just provide the value in the mdev_driver at registration time
and the core code takes care of maintaining it and exposing the value in
sysfs.

[hch: count instances per-parent instead of per-type, use an atomic_t
to avoid taking mdev_list_lock in the show method]

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-15-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: remove mtype_get_parent_dev

Just open code the dereferences in the only user.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jas

vfio/mdev: remove mtype_get_parent_dev

Just open code the dereferences in the only user.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-10-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: remove mdev_parent_dev

Just open code the dereferences in the only user.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Ti

vfio/mdev: remove mdev_parent_dev

Just open code the dereferences in the only user.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220923092652.100656-9-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: remove mdev_from_dev

Just open code it in the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian

vfio/mdev: remove mdev_from_dev

Just open code it in the only caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220923092652.100656-7-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: simplify mdev_type handling

Instead of abusing struct attribute_group to control initialization of
struct mdev_type, just define the actual attributes in the mdev_driver,
allocate the mde

vfio/mdev: simplify mdev_type handling

Instead of abusing struct attribute_group to control initialization of
struct mdev_type, just define the actual attributes in the mdev_driver,
allocate the mdev_type structures in the caller and pass them to
mdev_register_parent.

This allows the caller to use container_of to get at the containing
structure and thus significantly simplify the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-6-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: embedd struct mdev_parent in the parent data structure

Simplify mdev_{un}register_device by requiring the caller to pass in
a structure allocate as part of the parent device structure. T

vfio/mdev: embedd struct mdev_parent in the parent data structure

Simplify mdev_{un}register_device by requiring the caller to pass in
a structure allocate as part of the parent device structure. This
removes the need for a list of parents and the separate mdev_parent
refcount as we can simplify rely on the reference to the parent device.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-5-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: make mdev.h standalone includable

Include <linux/device.h> and <linux/uuid.h> so that users of this headers
don't need to do that and remove those includes that aren't needed
any more.

S

vfio/mdev: make mdev.h standalone includable

Include <linux/device.h> and <linux/uuid.h> so that users of this headers
don't need to do that and remove those includes that aren't needed
any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220923092652.100656-4-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Use the driver core to create the 'remove' file

The device creator is supposed to use the dev.groups value to add sysfs
files before device_add is called, not call sysfs_create_files() af

vfio/mdev: Use the driver core to create the 'remove' file

The device creator is supposed to use the dev.groups value to add sysfs
files before device_add is called, not call sysfs_create_files() after
device_add() returns. This creates a race with uevent delivery where the
extra attribute will not be visible.

This was being done because the groups had been co-opted by the mdev
driver, now that prior patches have moved the driver's groups to the
struct device_driver the dev.group is properly free for use here.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220411141403.86980-34-hch@lst.de
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>

show more ...

vfio/mdev: Remove mdev_parent_ops

The last useful member in this struct is the supported_type_groups, move
it to the mdev_driver and delete mdev_parent_ops.

Replace it with mdev_driver as an argume

vfio/mdev: Remove mdev_parent_ops

The last useful member in this struct is the supported_type_groups, move
it to the mdev_driver and delete mdev_parent_ops.

Replace it with mdev_driver as an argument to mdev_register_device()

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220411141403.86980-33-hch@lst.de
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>

show more ...

vfio/mdev: Remove vfio_mdev.c

Now that all mdev drivers directly create their own mdev_device driver and
directly register with the vfio core's vfio_device_ops this is all dead
code.

Delete vfio_md

vfio/mdev: Remove vfio_mdev.c

Now that all mdev drivers directly create their own mdev_device driver and
directly register with the vfio core's vfio_device_ops this is all dead
code.

Delete vfio_mdev.c and the mdev_parent_ops members that are connected to
it.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zhi Wang <zhi.a.wang@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220411141403.86980-31-hch@lst.de
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>

show more ...

vfio/mdev: don't warn if ->request is not set

Only a single driver actually sets the ->request method, so don't print
a scary warning if it isn't.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Revi

vfio/mdev: don't warn if ->request is not set

Only a single driver actually sets the ->request method, so don't print
a scary warning if it isn't.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20210726143524.155779-3-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: turn mdev_init into a subsys_initcall

Without this setups with buіlt-in mdev and mdev-drivers fail to
register like this:

[1.903149] Driver 'intel_vgpu_mdev' was unable to register with

vfio/mdev: turn mdev_init into a subsys_initcall

Without this setups with buіlt-in mdev and mdev-drivers fail to
register like this:

[1.903149] Driver 'intel_vgpu_mdev' was unable to register with bus_type 'mdev' because the bus was not initialized.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20210726143524.155779-2-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind

This allows a mdev driver to opt out of using vfio_mdev.c, instead the
driver will provide a 'struct mdev_driver' and regist

vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind

This allows a mdev driver to opt out of using vfio_mdev.c, instead the
driver will provide a 'struct mdev_driver' and register directly with the
driver core.

Much of mdev_parent_ops becomes unused in this mode:
- create()/remove() are done via the mdev_driver probe()/remove()
- mdev_attr_groups becomes mdev_driver driver.dev_groups
- Wrapper function callbacks are replaced with the same ones from
struct vfio_device_ops

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20210617142218.1877096-8-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE

For some reason the vfio_mdev shim mdev_driver has its own module and
kconfig. As the next patch requires access to it from mdev.ko merge the
two modules to

vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE

For some reason the vfio_mdev shim mdev_driver has its own module and
kconfig. As the next patch requires access to it from mdev.ko merge the
two modules together and remove VFIO_MDEV_DEVICE.

A later patch deletes this driver entirely.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20210617142218.1877096-7-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Correct the function signatures for the mdev_type_attributes

The driver core standard is to pass in the properly typed object, the
properly typed attribute and the buffer data. It stems f

vfio/mdev: Correct the function signatures for the mdev_type_attributes

The driver core standard is to pass in the properly typed object, the
properly typed attribute and the buffer data. It stems from the root
kobject method:

ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,..)

Each subclass of kobject should provide their own function with the same
signature but more specific types, eg struct device uses:

ssize_t (*show)(struct device *dev, struct device_attribute *attr,..)

In this case the existing signature is:

ssize_t (*show)(struct kobject *kobj, struct device *dev,..)

Where kobj is a 'struct mdev_type *' and dev is 'mdev_type->parent->dev'.

Change the mdev_type related sysfs attribute functions to:

ssize_t (*show)(struct mdev_type *mtype, struct mdev_type_attribute *attr,..)

In order to restore type safety and match the driver core standard

There are no current users of 'attr', but if it is ever needed it would be
hard to add in retroactively, so do it now.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <18-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Remove kobj from mdev_parent_ops->create()

The kobj here is a type-erased version of mdev_type, which is already
stored in the struct mdev_device being passed in. It was only ever used to

vfio/mdev: Remove kobj from mdev_parent_ops->create()

The kobj here is a type-erased version of mdev_type, which is already
stored in the struct mdev_device being passed in. It was only ever used to
compute the type_group_id, which is now extracted directly from the mdev.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <17-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Add mdev/mtype_get_type_group_id()

This returns the index in the supported_type_groups array that is
associated with the mdev_type attached to the struct mdev_device or its
containing str

vfio/mdev: Add mdev/mtype_get_type_group_id()

This returns the index in the supported_type_groups array that is
associated with the mdev_type attached to the struct mdev_device or its
containing struct kobject.

Each mdev_device can be spawned from exactly one mdev_type, which in turn
originates from exactly one supported_type_group.

Drivers are using weird string calculations to try and get back to this
index, providing a direct access to the index removes a bunch of wonky
driver code.

mdev_type->group can be deleted as the group is obtained using the
type_group_id.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <11-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Remove duplicate storage of parent in mdev_device

mdev_device->type->parent is the same thing.

The struct mdev_device was relying on the kref on the mdev_parent to also
indirectly hold a

vfio/mdev: Remove duplicate storage of parent in mdev_device

mdev_device->type->parent is the same thing.

The struct mdev_device was relying on the kref on the mdev_parent to also
indirectly hold a kref on the mdev_type pointer. Now that the type holds a
kref on the parent we can directly kref the mdev_type and remove this
implicit relationship.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <10-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Add missing error handling to dev_set_name()

This can fail, and seems to be a popular target for syzkaller error
injection. Check the error return and unwind with put_device().

Fixes: 7b

vfio/mdev: Add missing error handling to dev_set_name()

This can fail, and seems to be a popular target for syzkaller error
injection. Check the error return and unwind with put_device().

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <9-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Reorganize mdev_device_create()

Once the memory for the struct mdev_device is allocated it should
immediately be device_initialize()'d and filled in so that put_device()
can always be use

vfio/mdev: Reorganize mdev_device_create()

Once the memory for the struct mdev_device is allocated it should
immediately be device_initialize()'d and filled in so that put_device()
can always be used to undo the allocation.

Place the mdev_get/put_parent() so that they are clearly protecting the
mdev->parent pointer. Move the final put to the release function so that
the lifetime rules are trivial to understand. Update the goto labels to
follow the normal convention.

Remove mdev_device_free() as the release function via device_put() is now
usable in all cases.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <8-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

show more ...

vfio/mdev: Expose mdev_get/put_parent to mdev_private.h

The next patch will use these in mdev_sysfs.c

While here remove the now dead code checks for NULL, a mdev_type can never
have a NULL parent.

vfio/mdev: Expose mdev_get/put_parent to mdev_private.h

The next patch will use these in mdev_sysfs.c

While here remove the now dead code checks for NULL, a mdev_type can never
have a NULL parent.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <6-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/mdev: Use struct mdev_type in struct mdev_device

The kobj pointer in mdev_device is actually pointing at a struct
mdev_type. Use the proper type so things are understandable.

There are a numbe

vfio/mdev: Use struct mdev_type in struct mdev_device

The kobj pointer in mdev_device is actually pointing at a struct
mdev_type. Use the proper type so things are understandable.

There are a number of places that are confused and passing both the mdev
and the mtype as function arguments, fix these to derive the mtype
directly from the mdev to remove the redundancy.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <5-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio/mdev: Add missing typesafety around mdev_device

The mdev API should accept and pass a 'struct mdev_device *' in all
places, not pass a 'struct device *' and cast it internally with
to_mdev_devi

vfio/mdev: Add missing typesafety around mdev_device

The mdev API should accept and pass a 'struct mdev_device *' in all
places, not pass a 'struct device *' and cast it internally with
to_mdev_device(). Particularly in its struct mdev_driver functions, the
whole point of a bus's struct device_driver wrapper is to provide type
safety compared to the default struct device_driver.

Further, the driver core standard is for bus drivers to expose their
device structure in their public headers that can be used with
container_of() inlines and '&foo->dev' to go between the class levels, and
'&foo->dev' to be used with dev_err/etc driver core helper functions. Move
'struct mdev_device' to mdev.h

Once done this allows moving some one instruction exported functions to
static inlines, which in turns allows removing one of the two grotesque
symbol_get()'s related to mdev in the core code.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <3-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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vfio-mdev: Wire in a request handler for mdev parent

While performing some destructive tests with vfio-ccw, where the
paths to a device are forcible removed and thus the device itself
is unreachable

vfio-mdev: Wire in a request handler for mdev parent

While performing some destructive tests with vfio-ccw, where the
paths to a device are forcible removed and thus the device itself
is unreachable, it is rather easy to end up in an endless loop in
vfio_del_group_dev() due to the lack of a request callback for the
associated device.

In this example, one MDEV (77c) is used by a guest, while another
(77b) is not. The symptom is that the iommu is detached from the
mdev for 77b, but not 77c, until that guest is shutdown:

[ 238.794867] vfio_ccw 0.0.077b: MDEV: Unregistering
[ 238.794996] vfio_mdev 11f2d2bc-4083-431d-a023-eff72715c4f0: Removing from iommu group 2
[ 238.795001] vfio_mdev 11f2d2bc-4083-431d-a023-eff72715c4f0: MDEV: detaching iommu
[ 238.795036] vfio_ccw 0.0.077c: MDEV: Unregistering
...silence...

Let's wire in the request call back to the mdev device, so that a
device being physically removed from the host can be (gracefully?)
handled by the parent device at the time the device is removed.

Add a message when registering the device if a driver doesn't
provide this callback, so a clue is given that this same loop
may be encountered in a similar situation, and a message when
this occurs instead of the awkward silence noted above.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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