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[v1,12/16] Documentation: userspace-api: iommufd: Update vCMDQ

Message ID b31572a5171b6cdcc6822ca8c100512c8bf88858.1744353300.git.nicolinc@nvidia.com
State New
Headers show
Series iommufd: Add vIOMMU infrastructure (Part-4 vCMDQ) | expand

Commit Message

Nicolin Chen April 11, 2025, 6:37 a.m. UTC
With the introduction of the new object and its infrastructure, update the
doc to reflect that.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 Documentation/userspace-api/iommufd.rst | 11 +++++++++++
 1 file changed, 11 insertions(+)
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Patch

diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst
index b0df15865dec..ace0579432d5 100644
--- a/Documentation/userspace-api/iommufd.rst
+++ b/Documentation/userspace-api/iommufd.rst
@@ -124,6 +124,16 @@  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_VCMDQ, representing a hardware queue as a subset of a vIOMMU's
+  virtualization feature for a VM to directly execute guest-issued commands to
+  invalidate HW cache entries holding the mappings or translations of a guest-
+  owned stage-1 page table. Along with this queue object, iommufd provides the
+  user space a new mmap interface that the VMM can mmap a physical MMIO region
+  from the host physical address space to a guest physical address space. To use
+  this mmap interface, the VMM must define an IOMMU specific driver structure
+  to ask for a pair of VMA info (vm_pgoff/size) to do mmap after a vCMDQ gets
+  allocated.
+
 All user-visible objects are destroyed via the IOMMU_DESTROY uAPI.
 
 The diagrams below show relationships between user-visible objects and kernel
@@ -270,6 +280,7 @@  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_vcmdq for IOMMUFD_OBJ_VCMDQ.
 
 Several terminologies when looking at these datastructures: