From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 0/4] random,x86,kvm: Add and use MSR_KVM_GET_RNG_SEED
Date: Wed, 16 Jul 2014 09:13:23 -0700
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Cc: Daniel Borkmann <dborkman@redhat.com>,
	Gleb Natapov <gleb@kernel.org>, kvm list <kvm@vger.kernel.org>,
	"Theodore Ts'o" <tytso@mit.edu>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Kees Cook <keescook@chromium.org>, X86 ML <x86@kernel.org>,
	Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
	Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>
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On 07/16/2014 09:08 AM, Paolo Bonzini wrote:
> Il 16/07/2014 18:03, H. Peter Anvin ha scritto:
>> I suggested emulating RDRAND *but not set the CPUID bit*.  We already
>> developed a protocol in KVM/Qemu to enumerate emulated features (created
>> for MOVBE as I recall), specifically to service the semantic "feature X
>> will work but will be substantially slower than normal."
> 
> But those will set the CPUID bit.  There is currently no way for KVM
> guests to know if a CPUID bit is real or emulated.
> 

OK, so there wasn't any protocol implemented in the end.  I sit corrected.

	-hpa