From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1EFOuj-0000Wy-86 for qemu-devel@nongnu.org; Wed, 14 Sep 2005 00:30:30 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1EFOuN-0000Mq-CD for qemu-devel@nongnu.org; Wed, 14 Sep 2005 00:30:07 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1EFOuM-0000MV-SR for qemu-devel@nongnu.org; Wed, 14 Sep 2005 00:30:06 -0400 Received: from [32.97.110.131] (helo=e33.co.us.ibm.com) by monty-python.gnu.org with esmtp (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA:24) (Exim 4.34) id 1EFOtL-0002NV-Fd for qemu-devel@nongnu.org; Wed, 14 Sep 2005 00:29:08 -0400 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e33.co.us.ibm.com (8.12.10/8.12.9) with ESMTP id j8E4T0vd339328 for ; Wed, 14 Sep 2005 00:29:00 -0400 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by westrelay02.boulder.ibm.com (8.12.10/NCO/VERS6.7) with ESMTP id j8E4RitC541282 for ; Tue, 13 Sep 2005 22:27:44 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id j8E4RhkR024176 for ; Tue, 13 Sep 2005 22:27:44 -0600 Message-ID: <4327A6BB.1040509@us.ibm.com> Date: Tue, 13 Sep 2005 23:27:39 -0500 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] About qemu emulation speed (a question) and supported OS References: <1dc7f0e3050913053635cd61af@mail.gmail.com> <20050913214856.GA31111@jbrown.mylinuxbox.org> <43278F61.8060103@us.ibm.com> <200509140448.24354.mark.williamson@cl.cam.ac.uk> In-Reply-To: <200509140448.24354.mark.williamson@cl.cam.ac.uk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mark Williamson Cc: qemu-devel@nongnu.org Mark Williamson wrote: >>>No, I got the impression that Fabrice was taking about virtualization the >>>way VMware, old plex86, and vmbear (new FOSS x86 virtualizer in the >>>works) do it. >>> >>> >>The x86 cannot be "virtualized" in the Popek/Goldberg sense, so there's >>a couple of fast emulation techniques that are possible. Other than a >>hand coded dynamic translator, I reckon qemu + kqemu is about as good as >>it can get (unless I'm missing something here). Do you have >> >> > >Well, VMware does manage direct execution of some kernel code, I believe. >VMware's real super-cunningness is doing this as much as they can, instead of >emulating all the stuff. That said, I think with suitable optimisations >emulating all the kernel code could be acceptable. > >The unfortunate thing is that the guest can still tell it's in a VMware >machine (I'm not clear how) so it's not really *full* virtualisation, it's >just about epsilon away from it :-) VT / SVM will solve this properly. > > I reckon kqemu has this same problem... Technically, even in ring 3, if you run natively, you violate the Popek/Goldberg requirements because of cpuid. It's just not possible to trap it but it shouldn't matter for most software. >They have a (crazy but cool) idea that they'll one day be able to live-migrate >(i.e. without more than a few hundred ms downtime) virtual machines between >L4 hypervisors and Xen hypervisors. > > Yeah, how cool is that :-) Regards, Anthony Liguori >Cheers, >Mark > > > >>>>FWIW, Xen is already using QEMU in this way. It would be very neat to >>>>see this technique applied to a Type II VMM. >>>> >>>> >>>Do you have any details on this? >>> >>> >>Mark did a really good job of summarizing the current architecture. >> >>Regards, >> >>Anthony Liguori >> >> >> >>>>Regards, >>>> >>>>Anthony Liguori >>>> >>>> >>>>_______________________________________________ >>>>Qemu-devel mailing list >>>>Qemu-devel@nongnu.org >>>>http://lists.nongnu.org/mailman/listinfo/qemu-devel >>>> >>>> >>_______________________________________________ >>Qemu-devel mailing list >>Qemu-devel@nongnu.org >>http://lists.nongnu.org/mailman/listinfo/qemu-devel >> >> > > >