From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/30] nVMX: Nested VMX, v9 Date: Mon, 23 May 2011 17:34:20 +0300 Message-ID: <4DDA706C.1000200@redhat.com> References: <20110512154228.GA7943@fermat.math.technion.ac.il> <20110512155727.GA20193@redhat.com> <20110512163115.GA13138@fermat.math.technion.ac.il> <20110512165157.GC20193@redhat.com> <20110522193239.GA13130@fermat.math.technion.ac.il> <4DDA2E72.8070907@redhat.com> <20110523130226.GC23407@8bytes.org> <4DDA5C30.10107@redhat.com> <20110523134052.GD23407@8bytes.org> <4DDA66AF.7020505@redhat.com> <20110523142846.GE23407@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Nadav Har'El" , Gleb Natapov , kvm@vger.kernel.org, abelg@il.ibm.com To: Joerg Roedel Return-path: Received: from mx1.redhat.com ([209.132.183.28]:64386 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755333Ab1EWOe3 (ORCPT ); Mon, 23 May 2011 10:34:29 -0400 In-Reply-To: <20110523142846.GE23407@8bytes.org> Sender: kvm-owner@vger.kernel.org List-ID: On 05/23/2011 05:28 PM, Joerg Roedel wrote: > On Mon, May 23, 2011 at 04:52:47PM +0300, Avi Kivity wrote: > > On 05/23/2011 04:40 PM, Joerg Roedel wrote: > > >> The next benefit is that it works seemlessly even if the state that > >> needs to be transfered is extended (e.g. by emulating a new > >> virtualization hardware feature). This support can be implemented in the > >> kernel module and no changes to qemu are required. > > > > I agree it's a benefit. But I don't like making the fake vmexit part of > > live migration, if it turns out the wrong choice it's hard to undo it. > > Well, saving the state to the host-save-area and doing a fake-vmexit is > logically the same, only the memory where the information is stored > differs. Right. I guess the main difference is "info registers" after a stop. > To user-space we can provide a VCPU_FREEZE/VCPU_UNFREEZE ioctl which > does all the necessary things. > Or we can automatically flush things on any exit to userspace. They should be very rare in guest mode. -- error compiling committee.c: too many arguments to function