From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56823) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLpUM-00016f-9R for qemu-devel@nongnu.org; Wed, 20 Jan 2016 04:55:43 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aLpUH-00054f-BJ for qemu-devel@nongnu.org; Wed, 20 Jan 2016 04:55:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43504) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLpUH-00054R-5G for qemu-devel@nongnu.org; Wed, 20 Jan 2016 04:55:37 -0500 References: <1452851297-11198-1-git-send-email-liang.z.li@intel.com> <5698C735.3020409@huawei.com> <569CA9CC.80603@huawei.com> <569DA952.3090501@huawei.com> From: Paolo Bonzini Message-ID: <569F5993.3030204@redhat.com> Date: Wed, 20 Jan 2016 10:55:31 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] migration: not send zero page header in ram bulk stage List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Li, Liang Z" , Hailiang Zhang , "qemu-devel@nongnu.org" Cc: "amit.shah@redhat.com" , "peter.huangpeng@huawei.com" , "dgilbert@redhat.com" , "quintela@redhat.com" On 19/01/2016 04:17, Li, Liang Z wrote: > > Paolo is right, for VM in destination, QEMU may write VM's memory before > > VM starts. > > So your assumption that "VM's RAM pages are initialized to zero" is incorrect. > > This patch will break LM. > > Which portion of the VM's RAM pages will be written by QEMU? Do you know some exact information? > I can't wait for Paolo's response. It is basically anything that uses rom_add_file_fixed or rom_add_blob_fixed with an address that points into RAM. Paolo