Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751957Ab3CAHgo (ORCPT ); Fri, 1 Mar 2013 02:36:44 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:30085 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751221Ab3CAHgm (ORCPT ); Fri, 1 Mar 2013 02:36:42 -0500 X-IronPort-AV: E=Sophos;i="4.84,760,1355068800"; d="scan'208";a="6792898" Date: Fri, 1 Mar 2013 15:36:48 +0800 From: Hu Tao To: Eric Blake Cc: kvm list , qemu-devel , "linux-kernel@vger.kernel.org" , "Daniel P. Berrange" , KAMEZAWA Hiroyuki , Jan Kiszka , Gleb Natapov , Blue Swirl , Andrew Jones , Marcelo Tosatti , Sasha Levin , Luiz Capitulino , Anthony Liguori , Markus Armbruster , Paolo Bonzini , Stefan Hajnoczi , Juan Quintela , Orit Wasserman , Kevin Wolf , Wen Congyang , "Michael S. Tsirkin" , Alexander Graf , Alex Williamson , Peter Maydell Subject: Re: [PATCH v13 1/8] save/load cpu runstate Message-ID: <20130301073648.GD16362@localhost.localdomain> References: <512FC845.9080209@redhat.com> MIME-Version: 1.0 In-Reply-To: <512FC845.9080209@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/01 15:35:44, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2013/03/01 15:35:46, Serialize complete at 2013/03/01 15:35:46 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1530 Lines: 30 On Thu, Feb 28, 2013 at 02:12:37PM -0700, Eric Blake wrote: > On 02/28/2013 05:13 AM, Hu Tao wrote: > > This patch enables preservation of cpu runstate during save/load vm. > > So when a vm is restored from snapshot, the cpu runstate is restored, > > too. > > What happens if a management app wants to override the runstate when > restoring the domain? I can think of several useful scenarios: > > 1. management app pauses the guest, then saves domain state and other > things (management state, or disk clones), then resumes the guest. > Later, the management wants to revert to the saved state, but have the > guest running right away. I guess here, knowing that the guest was > saved in a paused state doesn't hurt, since the management app can > resume it right away. > > 2. management app saves domain state of a live guest, then copies that > state elsewhere. In its new location, the management app wants to > investigate the state for forensic analysis - so even though the guest > remembers that it was running, management wants to start it paused. > Here, it is important that there must not be a window of time where the > guest can run, otherwise, the results are not reproducible. -S takes precedence in the case. But for in-migration, runstate is loaded from src. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/