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2018-01-09vfio: mdev: make a couple of functions and structure vfio_mdev_driver staticXiongwei Song1-3/+3
The functions vfio_mdev_probe, vfio_mdev_remove and the structure vfio_mdev_driver are only used in this file, so make them static. Clean up sparse warnings: drivers/vfio/mdev/vfio_mdev.c:114:5: warning: no previous prototype for 'vfio_mdev_probe' [-Wmissing-prototypes] drivers/vfio/mdev/vfio_mdev.c:121:6: warning: no previous prototype for 'vfio_mdev_remove' [-Wmissing-prototypes] Signed-off-by: Xiongwei Song <sxwjean@gmail.com> Reviewed-by: Quan Xu <quan.xu0@gmail.com> Reviewed-by: Liu, Yi L <yi.l.liu@intel.com> Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2017-02-08vfio/mdev: Use a module softdep for vfio_mdevAlex Williamson1-12/+2
Use an explicit module softdep rather than a request module call such that the dependency is exposed to userspace. This allows us to more easily support modules loaded at initrd time. Reviewed by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-12-30vfio-mdev: Make mdev_device private and abstract interfacesAlex Williamson2-0/+43
Abstract access to mdev_device so that we can define which interfaces are public rather than relying on comments in the structure. Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Jike Song <jike.song@intel.com> Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
2016-12-30vfio-mdev: Make mdev_parent privateAlex Williamson2-0/+16
Rather than hoping for good behavior by marking some elements internal, enforce it by making the entire structure private and creating an accessor function for the one useful external field. Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
2016-12-30vfio-mdev: de-polute the namespace, rename parent_device & parent_opsAlex Williamson4-27/+27
Add an mdev_ prefix so we're not poluting the namespace so much. Cc: Zhenyu Wang <zhenyuw@linux.intel.com> Cc: Zhi Wang <zhi.a.wang@intel.com> Cc: Jike Song <jike.song@intel.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed by: Kirti Wankhede <kwankhede@nvidia.com>
2016-12-30vfio-mdev: Fix remove raceAlex Williamson1-2/+34
Using the mtty mdev sample driver we can generate a remove race by starting one shell that continuously creates mtty devices and several other shells all attempting to remove devices, in my case four remove shells. The fault occurs in mdev_remove_sysfs_files() where the passed type arg is NULL, which suggests we've received a struct device in mdev_device_remove() but it's in some sort of teardown state. The solution here is to make use of the accidentally unused list_head on the mdev_device such that the mdev core keeps a list of all the mdev devices. This allows us to validate that we have a valid mdev before we start removal, remove it from the list to prevent others from working on it, and if the vendor driver refuses to remove, we can re-add it to the list. Cc: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17docs: Add Documentation for Mediated devicesKirti Wankhede1-0/+1
Add file Documentation/vfio-mediated-device.txt that include details of mediated device framework. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: VFIO based driver for Mediated devicesKirti Wankhede4-1/+168
vfio_mdev driver registers with mdev core driver. mdev core driver creates mediated device and calls probe routine of vfio_mdev driver for each device. Probe routine of vfio_mdev driver adds mediated device to VFIO core module This driver forms a shim layer that pass through VFIO devices operations to vendor driver for mediated devices. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Jike Song <jike.song@intel.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
2016-11-17vfio: Mediated device Core driverKirti Wankhede6-0/+833
Design for Mediated Device Driver: Main purpose of this driver is to provide a common interface for mediated device management that can be used by different drivers of different devices. This module provides a generic interface to create the device, add it to mediated bus, add device to IOMMU group and then add it to vfio group. Below is the high Level block diagram, with Nvidia, Intel and IBM devices as example, since these are the devices which are going to actively use this module as of now. +---------------+ | | | +-----------+ | mdev_register_driver() +--------------+ | | | +<------------------------+ __init() | | | mdev | | | | | | bus | +------------------------>+ |<-> VFIO user | | driver | | probe()/remove() | vfio_mdev.ko | APIs | | | | | | | +-----------+ | +--------------+ | | | MDEV CORE | | MODULE | | mdev.ko | | +-----------+ | mdev_register_device() +--------------+ | | | +<------------------------+ | | | | | | nvidia.ko |<-> physical | | | +------------------------>+ | device | | | | callback +--------------+ | | Physical | | | | device | | mdev_register_device() +--------------+ | | interface | |<------------------------+ | | | | | | i915.ko |<-> physical | | | +------------------------>+ | device | | | | callback +--------------+ | | | | | | | | mdev_register_device() +--------------+ | | | +<------------------------+ | | | | | | ccw_device.ko|<-> physical | | | +------------------------>+ | device | | | | callback +--------------+ | +-----------+ | +---------------+ Core driver provides two types of registration interfaces: 1. Registration interface for mediated bus driver: /** * struct mdev_driver - Mediated device's driver * @name: driver name * @probe: called when new device created * @remove:called when device removed * @driver:device driver structure * **/ struct mdev_driver { const char *name; int (*probe) (struct device *dev); void (*remove) (struct device *dev); struct device_driver driver; }; Mediated bus driver for mdev device should use this interface to register and unregister with core driver respectively: int mdev_register_driver(struct mdev_driver *drv, struct module *owner); void mdev_unregister_driver(struct mdev_driver *drv); Mediated bus driver is responsible to add/delete mediated devices to/from VFIO group when devices are bound and unbound to the driver. 2. Physical device driver interface This interface provides vendor driver the set APIs to manage physical device related work in its driver. APIs are : * dev_attr_groups: attributes of the parent device. * mdev_attr_groups: attributes of the mediated device. * supported_type_groups: attributes to define supported type. This is mandatory field. * create: to allocate basic resources in vendor driver for a mediated device. This is mandatory to be provided by vendor driver. * remove: to free resources in vendor driver when mediated device is destroyed. This is mandatory to be provided by vendor driver. * open: open callback of mediated device * release: release callback of mediated device * read : read emulation callback. * write: write emulation callback. * ioctl: ioctl callback. * mmap: mmap emulation callback. Drivers should use these interfaces to register and unregister device to mdev core driver respectively: extern int mdev_register_device(struct device *dev, const struct parent_ops *ops); extern void mdev_unregister_device(struct device *dev); There are no locks to serialize above callbacks in mdev driver and vfio_mdev driver. If required, vendor driver can have locks to serialize above APIs in their driver. Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com> Signed-off-by: Neo Jia <cjia@nvidia.com> Reviewed-by: Jike Song <jike.song@intel.com> Reviewed-by: Dong Jia Shi <bjsdjshi@linux.vnet.ibm.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

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