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Re: [Qemu-devel] Re: [PATCH 1/2] allow hypervisor CPUID bit to be overri

From: Avi Kivity
Subject: Re: [Qemu-devel] Re: [PATCH 1/2] allow hypervisor CPUID bit to be overriden
Date: Tue, 23 Jun 2009 14:35:35 +0300
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On 06/23/2009 02:31 PM, Paul Brook wrote:
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.

I agree it's pointless, but it is a Microsoft requirement for passing their SVVP tests. Enabling it by default makes life a little easier for users who wish to validate their hypervisor and has no drawbacks.

error compiling committee.c: too many arguments to function

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