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Re: [Xen-devel] Questions on EPT dump and creation


At 18:57 +0800 on 19 Jul (1311101864), YAO wrote:
> I copied exactly every mapping one by one, but when I dumped the gfn->mfn
> mapping(I've modified ept_dump_p2m_table to find unequal entry),
> there are some strange output like this:
> (XEN) gfn: 200  mfn: 117def  my_mfn: 10d600
> (XEN) gfn: 400  mfn: 117dee  my_mfn: 111200
> (XEN) gfn: 600  mfn: 117ded  my_mfn: 111000
> (XEN) gfn: 800  mfn: 117dec  my_mfn: 10de00
> ......
> (XEN) gfn: 14a00  mfn: 1176bb  my_mfn: 10800
> (XEN) gfn: 14c00  mfn: 1176ba  my_mfn: 10600
> (XEN) gfn: 14e00  mfn: 1176b9  my_mfn: 10400
> (XEN) gfn: 15000  mfn: 1176b8  my_mfn: 10200
> ......
> (XEN) gfn: 1f600  mfn: 117b46  my_mfn: 4200
> (XEN) gfn: 1f800  mfn: 117b45  my_mfn: 4000
> It shouldn't have any unequal entry, I thought...and
> Every mismatch has a step of 0x200 until 0x1f800, which really confused me.

Hmmm.  The "my_mfn" values go up in 0x200s (which is the size of a
full EPT page) too but the "mfn" values go down 1 at a time.  I suspect
that your code is confused somewhere about the number of levels in the
EPT tables.


Tim Deegan <Tim.Deegan@xxxxxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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