From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 1/7] Nested VMX patch 1 implements vmon and vmoff Date: Mon, 21 Dec 2009 18:00:10 +0200 Message-ID: <4B2F9B8A.9070804@redhat.com> References: <1260470309-7166-1-git-send-email-oritw@il.ibm.com> <1260470309-7166-2-git-send-email-oritw@il.ibm.com> <20091220142018.GI4490@redhat.com> <87eimpefpn.fsf@basil.nowhere.org> <4B2E7551.6050201@redhat.com> <20091221155206.GE2500@il.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Andi Kleen , Gleb Natapov , Orit Wasserman , kvm@vger.kernel.org, Ben-Ami Yassour1 , Abel Gordon , aliguori@us.ibm.com, mdday@us.ibm.com To: Muli Ben-Yehuda Return-path: Received: from mx1.redhat.com ([209.132.183.28]:4419 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756622AbZLUQAa (ORCPT ); Mon, 21 Dec 2009 11:00:30 -0500 In-Reply-To: <20091221155206.GE2500@il.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On 12/21/2009 05:52 PM, Muli Ben-Yehuda wrote: > > I would say that VMX only supports nesting if you define "supports" as > "does not make it impossible". The fact that VMX operations in > executed in non-root mode are trapped is welcome, but there's so much > more that could be done in hardware to make nesting "better supported" > that I would hesitate to say that the current generation of VMX > supports nesting. > I would phrase it as "there is so much less the hardware can do to make nesting better supported" (such as avoid using vmread/vmwrite). As nested svm shows, you don't really need much (nested paging is very important though). -- error compiling committee.c: too many arguments to function