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RE: [Xen-devel] A simple question of CPU emulation in Xen

To: "MaoXiaoyun" <tinnycloud@xxxxxxxxxxx>, "xen devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] A simple question of CPU emulation in Xen
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Sat, 14 May 2011 09:41:39 +1000
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Thread-topic: [Xen-devel] A simple question of CPU emulation in Xen
> Hi :
>      I have a simple question on CPU emulation in Xen.
>     Currently, inside guest, we can see that the CPU information
> types and frequency is exactly
> same as physical CPU. Is it possible for Xen(or qemu) to emulate a
> type of CPU. That is inside
> guest, we see a different CPU types?
>     If it is possible, could someone elighten me where to start.

Do you want to emulate a completely different platform (eg PPC / alpha /
Sparc) or just pretend the cpu is a slightly different flavours (eg
running a late model Xeon CPU but emulate a P2)?

In a lot of cases you can do the latter by changing some CPUID values in
the DomU config to mask the CPU features so the guest thinks it is
running on an older model.


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