From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47553) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YcUSb-0001Gi-Fh for qemu-devel@nongnu.org; Mon, 30 Mar 2015 03:50:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YcUSY-0005Dj-Aj for qemu-devel@nongnu.org; Mon, 30 Mar 2015 03:50:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37729) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YcUSY-0005DZ-2d for qemu-devel@nongnu.org; Mon, 30 Mar 2015 03:50:10 -0400 Message-ID: <55190020.6020308@redhat.com> Date: Mon, 30 Mar 2015 09:49:52 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <5518BAC6.4090906@cn.fujitsu.com> In-Reply-To: <5518BAC6.4090906@cn.fujitsu.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 0/7] QEMU memory hot unplug support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Zhu Guihua , qemu-devel@nongnu.org, imammedo@redhat.com, quintela@redhat.com, amit.shah@redhat.com Cc: guz.fnst@cn.fujitsu.com, izumi.taku@jp.fujitsu.com, tangchen@cn.fujitsu.com On 30/03/2015 04:53, Zhu Guihua wrote: > Question: > > When migrating from old qemu to one with this hot remove feature, I found > this feature would not work any more in new qemu. > > The reason is that DSDT table will not re-generate in new qemu when > migration. > So the hot remove will not work in the new qemu even though qemu > has this feature. > > Is it possible to re-generate dsdt table when migration? No, consider the case when the OS is _executing_ the DSDT table during migration! You can either ignore the issue, or disable hot-unplug for older machine types---that is, only enable it for pc-2.4. Then you'll get consistent behavior wherever the VM is started in a cluster. Paolo