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Date: Mon, 24 Oct 2016 16:02:57 +0800
From: Peter Xu <peterx@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v4 RESEND 3/3] IOMMU: enable intel_iommu
 map and unmap notifiers
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To: "Aviv B.D." <bd.aviv@gmail.com>
Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, Jan Kiszka <jan.kiszka@siemens.com>

On Mon, Oct 24, 2016 at 10:53:01AM +0300, Aviv B.D. wrote:

[...]

> This was my first algorithm, but VFIO do not support remapping of mapped
> page.
> Before each MAP operation in VFIO one must do unmap, and therefore I'm
> sending
> the unmap notifications blindly before.
> I can rearrange my code closer to your suggestion.

If so, I would suggest we solve the real problem first: we should not
notify VFIO twice on map(), but only once. IMO either Alex's or
David's suggestion (in the other mail) is a good start.

> 
> 
> >
> > This is to follow your logic. I don't know whether this is efficient
> > enough, maybe good for the first version. The problem is, when you
> > call translate(), you will need to go over the page every time from
> > root dir. A faster way may be: provide a function to walk specific
> > address range. If you are going to implement the replay logic that
> > Alex/David has mentioned, maybe that will help too (walk over the
> > whole 64bit range).
> >
> > Interesting idea, but I prefer to add it in separate patch set after this
> one committed, if it's OK.

Sure.

-- peterx