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Diffstat (limited to 'Documentation/driver-api/vfio.rst')
| -rw-r--r-- | Documentation/driver-api/vfio.rst | 82 |
1 files changed, 60 insertions, 22 deletions
diff --git a/Documentation/driver-api/vfio.rst b/Documentation/driver-api/vfio.rst index c663b6f97825..50b690f7f663 100644 --- a/Documentation/driver-api/vfio.rst +++ b/Documentation/driver-api/vfio.rst @@ -249,19 +249,21 @@ VFIO bus driver API VFIO bus drivers, such as vfio-pci make use of only a few interfaces into VFIO core. When devices are bound and unbound to the driver, -the driver should call vfio_register_group_dev() and -vfio_unregister_group_dev() respectively:: +Following interfaces are called when devices are bound to and +unbound from the driver:: - void vfio_init_group_dev(struct vfio_device *device, - struct device *dev, - const struct vfio_device_ops *ops); - void vfio_uninit_group_dev(struct vfio_device *device); int vfio_register_group_dev(struct vfio_device *device); + int vfio_register_emulated_iommu_dev(struct vfio_device *device); void vfio_unregister_group_dev(struct vfio_device *device); -The driver should embed the vfio_device in its own structure and call -vfio_init_group_dev() to pre-configure it before going to registration -and call vfio_uninit_group_dev() after completing the un-registration. +The driver should embed the vfio_device in its own structure and use +vfio_alloc_device() to allocate the structure, and can register +@init/@release callbacks to manage any private state wrapping the +vfio_device:: + + vfio_alloc_device(dev_struct, member, dev, ops); + void vfio_put_device(struct vfio_device *device); + vfio_register_group_dev() indicates to the core to begin tracking the iommu_group of the specified dev and register the dev as owned by a VFIO bus driver. Once vfio_register_group_dev() returns it is possible for userspace to @@ -270,28 +272,64 @@ ready before calling it. The driver provides an ops structure for callbacks similar to a file operations structure:: struct vfio_device_ops { - int (*open)(struct vfio_device *vdev); + char *name; + int (*init)(struct vfio_device *vdev); void (*release)(struct vfio_device *vdev); + int (*bind_iommufd)(struct vfio_device *vdev, + struct iommufd_ctx *ictx, u32 *out_device_id); + void (*unbind_iommufd)(struct vfio_device *vdev); + int (*attach_ioas)(struct vfio_device *vdev, u32 *pt_id); + int (*open_device)(struct vfio_device *vdev); + void (*close_device)(struct vfio_device *vdev); ssize_t (*read)(struct vfio_device *vdev, char __user *buf, size_t count, loff_t *ppos); - ssize_t (*write)(struct vfio_device *vdev, - const char __user *buf, - size_t size, loff_t *ppos); + ssize_t (*write)(struct vfio_device *vdev, const char __user *buf, + size_t count, loff_t *size); long (*ioctl)(struct vfio_device *vdev, unsigned int cmd, unsigned long arg); - int (*mmap)(struct vfio_device *vdev, - struct vm_area_struct *vma); + int (*mmap)(struct vfio_device *vdev, struct vm_area_struct *vma); + void (*request)(struct vfio_device *vdev, unsigned int count); + int (*match)(struct vfio_device *vdev, char *buf); + void (*dma_unmap)(struct vfio_device *vdev, u64 iova, u64 length); + int (*device_feature)(struct vfio_device *device, u32 flags, + void __user *arg, size_t argsz); }; Each function is passed the vdev that was originally registered -in the vfio_register_group_dev() call above. This allows the bus driver -to obtain its private data using container_of(). The open/release -callbacks are issued when a new file descriptor is created for a -device (via VFIO_GROUP_GET_DEVICE_FD). The ioctl interface provides -a direct pass through for VFIO_DEVICE_* ioctls. The read/write/mmap -interfaces implement the device region access defined by the device's -own VFIO_DEVICE_GET_REGION_INFO ioctl. +in the vfio_register_group_dev() or vfio_register_emulated_iommu_dev() +call above. This allows the bus driver to obtain its private data using +container_of(). + +:: + + - The init/release callbacks are issued when vfio_device is initialized + and released. + + - The open/close device callbacks are issued when the first + instance of a file descriptor for the device is created (eg. + via VFIO_GROUP_GET_DEVICE_FD) for a user session. + + - The ioctl callback provides a direct pass through for some VFIO_DEVICE_* + ioctls. + + - The [un]bind_iommufd callbacks are issued when the device is bound to + and unbound from iommufd. + + - The attach_ioas callback is issued when the device is attached to an + IOAS managed by the bound iommufd. The attached IOAS is automatically + detached when the device is unbound from iommufd. + + - The read/write/mmap callbacks implement the device region access defined + by the device's own VFIO_DEVICE_GET_REGION_INFO ioctl. + + - The request callback is issued when device is going to be unregistered, + such as when trying to unbind the device from the vfio bus driver. + - The dma_unmap callback is issued when a range of iovas are unmapped + in the container or IOAS attached by the device. Drivers which make + use of the vfio page pinning interface must implement this callback in + order to unpin pages within the dma_unmap range. Drivers must tolerate + this callback even before calls to open_device(). PPC64 sPAPR implementation note ------------------------------- |