[PATCH v2 15/22] Documentation: userspace-api: iommufd: Update vCMDQ

[Bagas Sanjaya]

On Fri, Apr 25, 2025 at 10:58:10PM -0700, Nicolin Chen wrote:
> +- 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 an mmap interface for VMM to mmap a physical MMIO region from the
> +  host physical address space to a guest physical address space, to exclusively
> +  control the allocated vCMDQ HW. Thus, when allocating a vCMDQ, the VMM must
> +  request a pair of VMA info (vm_pgoff/size) for a later mmap call. The length
> +  argument of an mmap call could be smaller than the given size for a paritial
> +  mmap, but the given vm_pgoff (as the addr argument of the mmap call) should
"... partial mmap, ..."
> +  never be offsetted, which also implies that the mmap will always start from
> +  the beginning of the physical MMIO region.
> +
 
Thanks.

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