With the introduction of the new object and its infrastructure, update the
doc and the vIOMMU graph to reflect that.
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
Documentation/userspace-api/iommufd.rst | 41 +++++++++++++++++++------
1 file changed, 32 insertions(+), 9 deletions(-)
diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst
index a8b7766c2849..8ba868ce7960 100644
--- a/Documentation/userspace-api/iommufd.rst
+++ b/Documentation/userspace-api/iommufd.rst
@@ -94,6 +94,19 @@ Following IOMMUFD objects are exposed to userspace:
backed by corresponding vIOMMU objects, in which case a guest OS would do
the "dispatch" naturally instead of VMM trappings.
+- IOMMUFD_OBJ_VDEVICE, representing a virtual device for an IOMMUFD_OBJ_DEVICE
+ against an IOMMUFD_OBJ_VIOMMU. This virtual device holds the device's virtual
+ information or attributes (related to the vIOMMU) in a VM. An immediate vDATA
+ example can be the virtual ID of the device on a vIOMMU, which is a unique ID
+ that VMM assigns to the device for a translation channel/port of the vIOMMU,
+ e.g. vSID of ARM SMMUv3, vDeviceID of AMD IOMMU, and vRID of Intel VT-d to a
+ Context Table. Potential use cases of some advanced security information can
+ be forwarded via this object too, such as security level or realm information
+ in a Confidential Compute Architecture. A VMM should create a vDEVICE object
+ to forward all the device information in a VM, when it connects a device to a
+ vIOMMU, which is a separate ioctl call from attaching the same device to an
+ HWPT_PAGING that the vIOMMU holds.
+
All user-visible objects are destroyed via the IOMMU_DESTROY uAPI.
The diagrams below show relationships between user-visible objects and kernel
@@ -133,16 +146,16 @@ creating the objects and links::
|____________| |____________| |______|
_______________________________________________________________________
- | iommufd (with vIOMMU) |
+ | iommufd (with vIOMMU/vDEVICE) |
| |
- | [5] |
- | _____________ |
- | | | |
- | |----------------| vIOMMU | |
- | | | | |
- | | | | |
- | | [1] | | [4] [2] |
- | | ______ | | _____________ ________ |
+ | [5] [6] |
+ | _____________ _____________ |
+ | | | | | |
+ | |----------------| vIOMMU |<---| vDEVICE |<----| |
+ | | | | |_____________| | |
+ | | | | | |
+ | | [1] | | [4] | [2] |
+ | | ______ | | _____________ _|______ |
| | | | | [3] | | | | | |
| | | IOAS |<---|(HWPT_PAGING)|<---| HWPT_NESTED |<--| DEVICE | |
| | |______| |_____________| |_____________| |________| |
@@ -215,6 +228,15 @@ creating the objects and links::
the vIOMMU object and the HWPT_PAGING, then this vIOMMU object can be used
as a nesting parent object to allocate an HWPT_NESTED object described above.
+6. IOMMUFD_OBJ_VDEVICE can be only manually created via the IOMMU_VDEVICE_ALLOC
+ uAPI, provided a viommu_id for an iommufd_viommu object and a dev_id for an
+ iommufd_device object. The vDEVICE object will be the binding between these
+ two parent objects. Another @virt_id will be also set via the uAPI providing
+ the iommufd core an index to store the vDEVICE object to a vDEVICE array per
+ vIOMMU. If necessary, the IOMMU driver may choose to implement a vdevce_alloc
+ op to init its HW for virtualization feature related to a vDEVICE. Successful
+ completion of this operation sets up the linkages between vIOMMU and device.
+
A device can only bind to an iommufd due to DMA ownership claim and attach to at
most one IOAS object (no support of PASID yet).
@@ -228,6 +250,7 @@ User visible objects are backed by following datastructures:
- iommufd_hwpt_paging for IOMMUFD_OBJ_HWPT_PAGING.
- iommufd_hwpt_nested for IOMMUFD_OBJ_HWPT_NESTED.
- iommufd_viommu for IOMMUFD_OBJ_VIOMMU.
+- iommufd_vdevice for IOMMUFD_OBJ_VDEVICE.
Several terminologies when looking at these datastructures:
--
2.43.0
