Re: [PATCH v5 05/19] iommufd: Document overview of iommufd

From: Jason Gunthorpe <jgg@nvidia.com>
To: Binbin Wu <binbin.wu@linux.intel.com>
Cc: bpf@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
	David Woodhouse <dwmw2@infradead.org>,
	iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
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Subject: Re: [PATCH v5 05/19] iommufd: Document overview of iommufd
Date: Wed, 30 Nov 2022 20:08:56 -0400	[thread overview]
Message-ID: <Y4fwmIYO6OCYxhSb@nvidia.com> (raw)
In-Reply-To: <f1077114-0f0c-0ec0-0dd7-8b6cbc26ebb1@linux.intel.com>

On Wed, Nov 30, 2022 at 11:06:51PM +0800, Binbin Wu wrote:

> > +iommufd_ioas serves as the metadata datastructure to manage how IOVA ranges are
> > +mapped to memory pages, composed of:
> > +
> > +- struct io_pagetable holding the IOVA map
> > +- struct iopt_areas
> 
> The struct name should be iopt_area, adding "s" is a typo or intented for
> plural?

Yes, plural, I'll add a quote:

- struct iopt_area's representing populated portions of IOVA

> > representing populated portions of IOVA
> > +- struct iopt_pages representing the storage of PFNs
> > +- struct iommu_domain representing the IO page table in the IOMMU
> > +- struct iopt_pages_access representing in-kernel users of PFNs
> > +- struct xarray pinned_pfns holding a list of pages pinned by in-kernel users
> > +
> > +Each iopt_pages represents a logical linear array of full PFNs. The PFNs are
> > +ultimately derived from userspave
> 
> typo, userspave -> userspace
> 
> 
> >   VAs via an mm_struct. Once they have been
> > +pinned the PFNs are stored in IOPTEs of an iommu_domain or inside the pinned_pages
> 
> pinned_pages -> pinned_pfns?

Yep

Got all the other stuff too!

Thanks,
Jason