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Date: Thu, 05 Jun 2014 18:58:17 +0200
From: Alexander Graf <agraf@suse.de>
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Subject: Re: [Qemu-devel] [RFC 0/2] GET_EMULATED_CPUID support with
	"allow-emulation" option
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To: Paolo Bonzini <pbonzini@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>, qemu-devel@nongnu.org
Cc: Michael Mueller <mimu@linux.vnet.ibm.com>, kvm@vger.kernel.org, "Michael S. Tsirkin" <mst@redhat.com>, Christian Borntraeger <borntraeger@de.ibm.com>, "Gabriel L. Somlo" <gsomlo@gmail.com>, Borislav Petkov <bp@alien8.de>, "Jason J. Herne" <jjherne@linux.vnet.ibm.com>, =?UTF-8?B?QW5kcmVhcyBGw6RyYmVy?= <afaerber@suse.de>


On 05.06.14 18:52, Paolo Bonzini wrote:
> Il 05/06/2014 18:45, Alexander Graf ha scritto:
>>>>
>>>
>>> Only if you were using "-cpu somethingThatHasAVX", though, no?
>>
>> Yes. The same argument goes the other way around. I want to use AVX
>> emulation, do "allow-emulation" and suddenly I get MONITOR/MWAIT 
>> emulation.
>
> What about:
>
> - letting "-cpu foo,+emulatedfeature" just work
>
> - adding emulated=yes that blindly enables all emulated features
>
> - making "-cpu ...,check" prints a warning for emulated features 
> unless emulated=yes

So:

   -cpu foo,+emulatedFeature just works

   -cpu foo,+notEmulatedFeature still sets the CPUID bit for that feature

   -cpu foo,check prints warnings for all cpuid bits not in the 
"allowed" bitmap. It prints different warnings depending on whether the 
bit is in "emulated" or not


Alex