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Re: [Xen-devel] guest physical to xen machine copy?

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, "Xen-Devel (E-mail)" <xen-devel@xxxxxxxxxxxxxxxxxxx>, "Tian, Kevin" <kevin.tian@xxxxxxxxx>
Subject: Re: [Xen-devel] guest physical to xen machine copy?
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Tue, 30 Sep 2008 07:24:33 +0100
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On 29/9/08 23:30, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> Then I gather I need to be passing an mfn to Xen instead
> of a gpfn.  To do so, it looks like I call pfn_to_mfn()
> in the paravirtualized guest.  But how can this work
> on a 32-bit-PV-on-64-bit-Xen since pfn_to_mfn() returns
> an unsigned long?

So what?

> Also, once I've got an (pvguest-translated-gpfn-to-) mfn
> inside of Xen, do I still do a gfn_to_mfn() on it?
> (Shouldn't matter because it just returns the gfn, right?)

Yes, gfn here means what-the-guest-thinks-is-an-mfn. That's pfn for an HVM
guest; mfn for a PV guest.

 -- Keir

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