Re: [PATCH v7 13/13] Documentation: userspace-api: iommufd: Update vIOMMU

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Tue, Nov 05, 2024 at 12:04:29PM -0800, Nicolin Chen wrote:
> With the introduction of the new object and its infrastructure, update the
> doc to reflect that and add a new graph.
> 
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>  Documentation/userspace-api/iommufd.rst | 69 ++++++++++++++++++++++++-
>  1 file changed, 68 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/userspace-api/iommufd.rst b/Documentation/userspace-api/iommufd.rst
> index 2deba93bf159..a8b7766c2849 100644
> --- a/Documentation/userspace-api/iommufd.rst
> +++ b/Documentation/userspace-api/iommufd.rst
> @@ -63,6 +63,37 @@ Following IOMMUFD objects are exposed to userspace:
>    space usually has mappings from guest-level I/O virtual addresses to guest-
>    level physical addresses.
>  
> +- IOMMUFD_OBJ_VIOMMU, representing a slice of the physical IOMMU instance,
> +  passed to or shared with a VM. It may be some HW-accelerated virtualization
> +  features and some SW resources used by the VM. For examples:
> +  * Security namespace for guest owned ID, e.g. guest-controlled cache tags
> +  * Non-device-affiliated event reporting, e.g. invalidation queue errors
> +  * Access to a sharable nesting parent pagetable across physical IOMMUs
> +  * Virtualization of various platforms IDs, e.g. RIDs and others
> +  * Delivery of paravirtualized invalidation
> +  * Direct assigned invalidation queues
> +  * Direct assigned interrupts

The bullet list above is outputted in htmldocs build as long-running paragraph
instead.

> +  Such a vIOMMU object generally has the access to a nesting parent pagetable
> +  to support some HW-accelerated virtualization features. So, a vIOMMU object
> +  must be created given a nesting parent HWPT_PAGING object, and then it would
> +  encapsulate that HWPT_PAGING object. Therefore, a vIOMMU object can be used
> +  to allocate an HWPT_NESTED object in place of the encapsulated HWPT_PAGING.

Thanks.

-- 
An old man doll... just what I always wanted! - Clara

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