user/sven/linux.git/include/linux/mdev.h, branch v5.15.44

vfio: Remove struct vfio_device_ops open/release

2021-08-11T15:50:11Z

Nothing uses this anymore, delete it. Signed-off-by: Yishai Hadas Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Reviewed-by: Cornelia Huck Link: https://lore.kernel.org/r/14-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com Signed-off-by: Alex Williamson

vfio: Provide better generic support for open/release vfio_device_ops

2021-08-11T15:50:10Z

Currently the driver ops have an open/release pair that is called once each time a device FD is opened or closed. Add an additional set of open/close_device() ops which are called when the device FD is opened for the first time and closed for the last time. An analysis shows that all of the drivers require this semantic. Some are open coding it as part of their reflck implementation, and some are just buggy and miss it completely. To retain the current semantics PCI and FSL depend on, introduce the idea of a "device set" which is a grouping of vfio_device's that share the same lock around opening. The device set is established by providing a 'set_id' pointer. All vfio_device's that provide the same pointer will be joined to the same singleton memory and lock across the whole set. This effectively replaces the oddly named reflck. After conversion the set_id will be sourced from: - A struct device from a fsl_mc_device (fsl) - A struct pci_slot (pci) - A struct pci_bus (pci) - The struct vfio_device (everything) The design ensures that the above pointers are live as long as the vfio_device is registered, so they form reliable unique keys to group vfio_devices into sets. This implementation uses xarray instead of searching through the driver core structures, which simplifies the somewhat tricky locking in this area. Following patches convert all the drivers. Signed-off-by: Yishai Hadas Reviewed-by: Cornelia Huck Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Link: https://lore.kernel.org/r/4-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com Signed-off-by: Alex Williamson

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

2021-06-21T21:29:25Z

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 Signed-off-by: Christoph Hellwig Reviewed-by: Cornelia Huck Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kirti Wankhede Link: https://lore.kernel.org/r/20210617142218.1877096-8-hch@lst.de Signed-off-by: Alex Williamson

vfio/mdev: Correct the function signatures for the mdev_type_attributes

2021-04-12T16:36:00Z

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 Reviewed-by: Cornelia Huck Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Message-Id: <18-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

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

2021-04-12T16:36:00Z

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 Reviewed-by: Cornelia Huck Reviewed-by: Christoph Hellwig Signed-off-by: Jason Gunthorpe Message-Id: <17-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

vfio/mdev: Add mdev/mtype_get_type_group_id()

2021-04-07T21:39:18Z

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 Reviewed-by: Kevin Tian Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Message-Id: <11-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

vfio/mdev: Remove duplicate storage of parent in mdev_device

2021-04-07T21:39:18Z

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 Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Message-Id: <10-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

vfio/mdev: Use struct mdev_type in struct mdev_device

2021-04-07T21:39:17Z

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 Reviewed-by: Kevin Tian Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Message-Id: <5-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

vfio/mdev: Simplify driver registration

2021-04-07T21:39:16Z

This is only done once, we don't need to generate code to initialize a structure stored in the ELF .data segment. Fill in the three required .driver members directly instead of copying data into them during mdev_register_driver(). Further the to_mdev_driver() function doesn't belong in a public header, just inline it into the two places that need it. Finally, we can now clearly see that 'drv' derived from dev->driver cannot be NULL, firstly because the driver core forbids it, and secondly because NULL won't pass through the container_of(). Remove the dead code. Reviewed-by: Christoph Hellwig Reviewed-by: Kevin Tian Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Message-Id: <4-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson

vfio/mdev: Add missing typesafety around mdev_device

2021-04-07T21:39:16Z

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 Reviewed-by: Cornelia Huck Signed-off-by: Jason Gunthorpe Reviewed-by: Christoph Hellwig Message-Id: <3-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com> Signed-off-by: Alex Williamson