From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [Qemu-devel] Re: [PATCH v2] qemu-kvm: Speed up of the dirty-bitmap-traveling Date: Wed, 10 Feb 2010 18:52:00 +0200 Message-ID: <4B72E430.4070700@redhat.com> References: <4B728FF9.6010707@lab.ntt.co.jp> <4B72B28E.6010801@redhat.com> <4B72D69D.7050005@codemonkey.ws> <4B72D838.9060603@suse.de> <4B72E051.8090008@codemonkey.ws> <4B72E224.1090901@suse.de> <4B72E2D2.7010701@redhat.com> <4B72E32F.3080205@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , OHMURA Kei , mtosatti@redhat.com, "qemu-devel@nongnu.org" , "kvm@vger.kernel.org" , Anthony Liguori To: Alexander Graf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43303 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754820Ab0BJQwU (ORCPT ); Wed, 10 Feb 2010 11:52:20 -0500 In-Reply-To: <4B72E32F.3080205@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: On 02/10/2010 06:47 PM, Alexander Graf wrote: >>> Because on PPC, you usually run PPC32 userspace code on a PPC64 kernel. >>> Unlike with x86, there's no real benefit in using 64 bit userspace. >>> >>> >>> >> btw, does 32-bit ppc qemu support large memory guests? It doesn't on >> x86, and I don't remember any hacks to support large memory guests >> elsewhere. >> >> > > It doesn't :-). In fact, the guest we virtualize wouldn't work with > 2 > GB anyways, because that needs an iommu implementation. > Oh, so you may want to revisit the "there's no real benefit in using 64 bit userspace". Seriously, that looks like a big deficiency. What would it take to implement an iommu? I imagine Anthony's latest patches are a first step in that journey. -- error compiling committee.c: too many arguments to function