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

Nicolin Chen nicolinc at nvidia.com
Mon Apr 28 12:00:14 PDT 2025


On Mon, Apr 28, 2025 at 09:31:31PM +0700, Bagas Sanjaya wrote:
> 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, ..."

Fixed. Thanks!

Nicolin



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