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Date: Mon, 22 Mar 2010 20:55:14 +0200
From: Avi Kivity <avi@redhat.com>
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To: Pekka Enberg <penberg@cs.helsinki.fi>
CC: "Frank Ch. Eigler" <fche@redhat.com>, Ingo Molnar <mingo@elte.hu>,
       Joerg Roedel <joro@8bytes.org>, Anthony Liguori <anthony@codemonkey.ws>,
       "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Sheng Yang <sheng@linux.intel.com>, linux-kernel@vger.kernel.org,
       kvm@vger.kernel.org, Marcelo Tosatti <mtosatti@redhat.com>,
       Jes Sorensen <Jes.Sorensen@redhat.com>, Gleb Natapov <gleb@redhat.com>,
       Zachary Amsden <zamsden@redhat.com>, ziteng.huang@intel.com,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Fr?d?ric Weisbecker <fweisbec@gmail.com>
Subject: Re: [RFC] Unify KVM kernel-space and user-space code into a single
 	project
References: <20100318172805.GB26067@elte.hu>	 <20100322111040.GL13108@8bytes.org> <20100322122228.GH3483@elte.hu>	 <20100322134633.GD1940@8bytes.org> <20100322163215.GC18796@elte.hu>	 <y0mmxy0wa1r.fsf@fche.csb>	 <84144f021003221027t1a3e7d6ft64612654c5e50da@mail.gmail.com>	 <4BA7A9AF.3010806@redhat.com>	 <84144f021003221052lb693f15ped0b432c34cdd8dc@mail.gmail.com>	 <4BA7B119.1070800@redhat.com> <84144f021003221110p79db476fpae25f6997b61b0b9@mail.gmail.com>
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On 03/22/2010 08:10 PM, Pekka Enberg wrote:
> On Mon, Mar 22, 2010 at 8:04 PM, Avi Kivity<avi@redhat.com>  wrote:
>    
>>> That said, pulling 400 KLOC of code into the kernel sounds really
>>> excessive. Would we need all that if we just do native virtualization
>>> and no actual emulation?
>>>        
>> What is native virtualization and no actual emulation?
>>      
> What I meant with "actual emulation" was running architecture A code
> on architecture B what was qemu's traditional use case. So the
> question was how much of the 400 KLOC do we need for just KVM on all
> the architectures that it supports?
>    

qemu is 620 KLOC.  Without cpu emulation that drops to ~480 KLOC.  Much 
of that is device emulation that is not supported by kvm now (like ARM) 
but some might be needed again in the future (like ARM).

x86-only is perhaps 300 KLOC, but kvm is not x86 only.

And that is with a rudimentary GUI.  GUIs are heavy.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.