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[Xen-devel] Identifying pagetype in they hypervisor

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] Identifying pagetype in they hypervisor
From: "Mike Sun" <msun@xxxxxxxxxx>
Date: Sun, 24 Aug 2008 20:47:19 -0400
Delivery-date: Sun, 24 Aug 2008 17:47:43 -0700
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Hi --

I'm working off of a bit older branch, 3.1.0, but hopefully the
question is still relevant.

In the suspend/restore code in 'tools/libxc/xc_domain_save.c', as part
of the saved record, a list of pfn_types are saved prior to the actual
pages themselves.  These pfn_types are pfns with a type bits
associated with them that are accessed with the XEN_DOMCTL_PFINFO_XTAB

I'm doing some copy-on-write work, and when I intercept writes in the
hypervisor, I need to copy both the actual page, and the type
associated with the page (so that it could later be properly written
out to the save record).  I've modified the shadow page table code to
handle write faults associated with CoW and am able to get the mfn of
the faulting page and perform the copy; I cannot seem to find where
given the mfn, I can find the page type associated with it.  Could
anybody help point me to the right place or direction?

Much thanks,

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