Documentation/userspace-api/iommufd.rst

85   Such a vIOMMU object generally has the access to a nesting parent pagetable
86   to support some HW-accelerated virtualization features. So, a vIOMMU object
88   encapsulate that HWPT_PAGING object. Therefore, a vIOMMU object can be used
93      The name "vIOMMU" isn't necessarily identical to a virtualized IOMMU in a
97      vIOMMU objects created for individual slices of different physical IOMMUs.
98      In other words, a vIOMMU object is always a representation of one physical
103      backed by corresponding vIOMMU objects, in which case a guest OS would do
108   information or attributes (related to the vIOMMU) in a VM. An immediate vDATA
109   example can be the virtual ID of the device on a vIOMMU, which is a unique ID
110   that VMM assigns to the device for a translation channel/port of the vIOMMU,
116   vIOMMU, which is a separate ioctl call from attaching the same device to an
117   HWPT_PAGING that the vIOMMU holds.
119 - IOMMUFD_OBJ_VEVENTQ, representing a software queue for a vIOMMU to report its
122   This queue object provides user space an FD to poll/read the vIOMMU events. A
123   vIOMMU object must be created first to get its viommu_id, which could be then
124   used to allocate a vEVENTQ. Each vIOMMU can support multiple types of vEVENTS,
166  |                      iommufd (with vIOMMU/vDEVICE)                    |
171  |      |----------------|    vIOMMU   |<---|   vDEVICE   |<----|        |
218    uAPI, provided an hwpt_id or a viommu_id of a vIOMMU object encapsulating a
237    uAPI, provided a dev_id (for the device's physical IOMMU to back the vIOMMU)
238    and an hwpt_id (to associate the vIOMMU to a nesting parent HWPT_PAGING). The
239    iommufd core will link the vIOMMU object to the struct iommu_device that the
241    to allocate its own vIOMMU data structure embedding the core-level structure
243    also configure its HW virtualization feature for that vIOMMU (and thus for
245    the vIOMMU object and the HWPT_PAGING, then this vIOMMU object can be used
253    vIOMMU. If necessary, the IOMMU driver may choose to implement a vdevce_alloc
255    completion of this operation sets up the linkages between vIOMMU and device.