From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH -v2] kvm: Emulate MOVBE
Date: Tue, 23 Apr 2013 16:50:43 -0700
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References: <20130414074107.GD17919@redhat.com> <20130414173215.GD20547@pd.tnic> <20130416174236.GE5807@redhat.com> <20130417110433.GD11807@pd.tnic> <20130417133829.GH1682@redhat.com> <20130417140200.GE11807@pd.tnic> <20130418224848.GA20712@pd.tnic> <20130421094651.GA8997@redhat.com> <20130421113051.GB4594@pd.tnic> <20130421125115.GD8997@redhat.com> <20130423234150.GA31444@pd.tnic>
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Cc: Gleb Natapov <gleb@redhat.com>, Andre Przywara <andre@andrep.de>,
	kvm@vger.kernel.org,
	=?UTF-8?B?SsO2cmcgUsO2ZGVs?= <joro@8bytes.org>,
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To: Borislav Petkov <bp@alien8.de>
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On 04/23/2013 04:41 PM, Borislav Petkov wrote:
> 
> Btw, in thinking about this more, I'm kinda sceptical we want to use the
> CPUID layout for this new KVM_GET_EMULATED_* ioctl. And the reason why
> I'm sceptical is that not every instruction is behind a CPUID capability
> bit and if we want to tell userspace that we do emulate any insn, even
> one for which there's no CPUID bit, we're going to have to either
> simulate a kvm-specific CPUID leaf or, maybe even better, come up with
> our own format for emulated capabilities. Maybe a bit vector with set
> bits for the respective capability, or something more nifty.
> 
> In any case, it doesn't really need to be CPUID-like, IMHO.
> 

Using CPUID has the major advantage that it is well-defined.

	-hpa