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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] Re: [PATCH 1/2] allow hypervisor CPUID bit to be
	overriden
Date: Tue, 23 Jun 2009 12:31:12 +0100
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To: qemu-devel@nongnu.org
Cc: Andre Przywara <andre.przywara@amd.com>, aliguori@us.ibm.com, Avi Kivity <avi@redhat.com>, kvm@vger.kernel.org

On Tuesday 23 June 2009, Avi Kivity wrote:
> On 06/23/2009 12:47 AM, Andre Przywara wrote:
> > KVM defaults to the hypervisor CPUID bit to be set, whereas pure QEMU
> > clears it. On some occasions one want to set or clear it the other way
> > round (for instance to get HyperV running inside a guest).
> > Allow the default to be overridden on the command line and fix some
> > whitespace damage on the way.
>
> It makes sense for qemu to set the hypervisor bit unconditionally.  A
> guest running under qemu is not bare metal.

I see no reason why a guest has to be told that it's running inside a VM.
In principle an appropriately configured qemu should be indistinguishable from 
real hardware. In practice it's technically infeasible to cover absolutely 
everything, but if we set this bit we're not even trying.

I have no objection to the bit being set by default for the QEMU CPU types.

Paul