From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: Question on QEMU restore process Date: Tue, 26 May 2015 16:49:28 +0100 Message-ID: <1432655368.14664.150.camel@citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "Lengyel, Tamas" Cc: xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Tue, 2015-05-26 at 17:38 +0200, Lengyel, Tamas wrote: > Hi all, > > I'm wondering if someone can point me in the right direction. I'm > trying to understand the process around domain save/restore using XL. > I can see the xl save format and how its appended with the QEMU state > aquired via the xen-save-devices-state qmp command (this is for > upstream QEMU). > > However, I have a hard time locating the exact point where that save > state is being loaded into the new QEMU process. I see in libxc that > it should be dumped into "/var/lib/xen/qemu-resume" appended by the > domain id of the newly created domain. It seems this was passed to > QEMU via the -loadvm flag at one point, but on Xen 4.4 I don't see > that flag on my QEMU processes when I restore a domain. libxl__build_device_model_args_new appears to pass it as "-incoming fd:N" where N is an open file descriptor which qemu will inherit from its parent (libxl). Ian.