From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: QEMU vs KVM Date: Wed, 12 Sep 2007 12:43:32 +0300 Message-ID: <46E7B4C4.8060101@qumranet.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: gerryw-dHy0zPTSVEVBDgjK7y7TUQ@public.gmane.org Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org gerryw-dHy0zPTSVEVBDgjK7y7TUQ@public.gmane.org wrote: > > Hi, > > Thanks! Sorry. Yes. I meant kqemu. > > Okay.. so would it be correct to say that kqemu formed the initial > base of what is now kvm/kvm_intel/kvm_amd No. > and that the mods to qemu are necessary for interfacing to the kernel > drivers and possibly some paravirtualized drivers for enhanced I/O > performance? Yes. > > Also.. when you say that kvm is part of the linux kernel do you mean > 2.6.20 and above? Yes. > Are the modules no longer necessary for the .20+ kernels? They are included in .20+. > > I know your very busy. I really appreciate your taking the time to > answer my questions. > > Thanks Again, > -G > > > > > > > > > *Avi Kivity * > > 09/12/2007 04:04 AM > > > To > gerryw-dHy0zPTSVEVBDgjK7y7TUQ@public.gmane.org > cc > kvm-devel > Subject > Re: [kvm-devel] QEMU vs KVM > > > > > > > > > > gerryw-dHy0zPTSVEVBDgjK7y7TUQ@public.gmane.org wrote: > > > > Hello All, > > > > I am a bit unclear about the differences between QEMU and KVM. If I > > understand correctly, QEMU can run in a mode on an x86 where it > > executes user space code directly on the cpu without emulation. This > > seems to be very similar to what KVM is doing with the exception of > > using the virtualization capability of the cpu. I would think there > > would be very little difference in performance between the two in this > > case. Please forgive my ignorance, because I don't know that much > > about the new VT cpus yet. What is the actual difference / objective > > of the KVM project? > > You're describing kqemu, not qemu. > > Qemu is an emulator; it can emualte a large number of guests on a large > number of hosts, albeit at fairly slow speeds. > > kqemu is a "qemu accelerator" which can be used to speed up qemu > emulation if the guest and host are the same. > > kvm is a hardware virtualization system that is part of the Linux > kernel. While at present the only serious user is a modified qemu, it > is not tied to qemu. It is faster than either qemu of kqemu. The > downside is that it requires hardware virtualization extensions for > fully virtualized guests. > > > > -- > error compiling committee.c: too many arguments to function > > -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2005. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/