diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2025-07-09 22:59:11 -0700 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2025-07-11 14:34:35 -0300 |
| commit | 035c9211f05befe3fa2765c00356d32974176a94 (patch) | |
| tree | 87dc8b5d04e6a49965bbca1c02e8104a56a0e0b8 /Documentation/userspace-api | |
| parent | 80478a2b450e984b5d270d0d7088912d64e84303 (diff) | |
Documentation: userspace-api: iommufd: Update HW QUEUE
With the introduction of the new object and its infrastructure, update the
doc to reflect that.
Link: https://patch.msgid.link/r/caa3ddc0d9bacf05c5b3e02c5f306ff3172cc54d.1752126748.git.nicolinc@nvidia.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'Documentation/userspace-api')
| -rw-r--r-- | Documentation/userspace-api/iommufd.rst | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst index b0df15865dec..03f7510384d2 100644 --- a/Documentation/userspace-api/iommufd.rst +++ b/Documentation/userspace-api/iommufd.rst @@ -124,6 +124,17 @@ Following IOMMUFD objects are exposed to userspace: used to allocate a vEVENTQ. Each vIOMMU can support multiple types of vEVENTS, but is confined to one vEVENTQ per vEVENTQ type. +- IOMMUFD_OBJ_HW_QUEUE, representing a hardware accelerated queue, as a subset + of IOMMU's virtualization features, for the IOMMU HW to directly read or write + the virtual queue memory owned by a guest OS. This HW-acceleration feature can + allow VM to work with the IOMMU HW directly without a VM Exit, so as to reduce + overhead from the hypercalls. Along with the HW QUEUE object, iommufd provides + user space an mmap interface for VMM to mmap a physical MMIO region from the + host physical address space to the guest physical address space, allowing the + guest OS to directly control the allocated HW QUEUE. Thus, when allocating a + HW QUEUE, the VMM must request a pair of mmap info (offset/length) and pass in + exactly to an mmap syscall via its offset and length arguments. + All user-visible objects are destroyed via the IOMMU_DESTROY uAPI. The diagrams below show relationships between user-visible objects and kernel @@ -270,6 +281,7 @@ User visible objects are backed by following datastructures: - iommufd_viommu for IOMMUFD_OBJ_VIOMMU. - iommufd_vdevice for IOMMUFD_OBJ_VDEVICE. - iommufd_veventq for IOMMUFD_OBJ_VEVENTQ. +- iommufd_hw_queue for IOMMUFD_OBJ_HW_QUEUE. Several terminologies when looking at these datastructures: |