From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Xu Subject: Re: [PATCH] migration: introduce decompress-error-check Date: Fri, 27 Apr 2018 17:31:35 +0800 Message-ID: <20180427093135.GC13269@xz-mi> References: <20180426091519.26934-1-xiaoguangrong@tencent.com> <32eaad8e-35a0-5240-37a2-4242b7890ab9@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: kvm@vger.kernel.org, mst@redhat.com, mtosatti@redhat.com, Xiao Guangrong , qemu-devel@nongnu.org, dgilbert@redhat.com, wei.w.wang@intel.com, jiang.biao2@zte.com.cn, pbonzini@redhat.com To: Xiao Guangrong Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel2=m.gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: kvm.vger.kernel.org On Fri, Apr 27, 2018 at 11:15:37AM +0800, Xiao Guangrong wrote: > > > On 04/26/2018 10:01 PM, Eric Blake wrote: > > On 04/26/2018 04:15 AM, guangrong.xiao@gmail.com wrote: > > > From: Xiao Guangrong > > > > > > QEMU 2.13 enables strict check for compression & decompression to > > > make the migration more robuster, that depends on the source to fix > > > > s/robuster/robust/ > > > > Will fix, thank you for pointing it out. > > > > the internal design which triggers the unexpected error conditions > > > > 2.13 hasn't been released yet. Why do we need a knob to explicitly turn > > off strict checking? Can we not instead make 2.13 automatically smart > > enough to tell if the incoming stream is coming from an older qemu > > (which might fail if the strict checks are enabled) vs. a newer qemu > > (the sender gave us what we need to ensure the strict checks are > > worthwhile)? > > > > Really smart. > > How about introduce a new command, MIG_CMD_DECOMPRESS_ERR_CHECK, > the destination will do strict check if got this command (i.e, new > QEMU is running on the source), otherwise, turn the check off. Why not we just introduce a compat bit for that? I mean something like: 15c3850325 ("migration: move skip_section_footers", 2017-06-28). Then we turn that check bit off for <=2.12. Would that work? (I would suspect that's what Eric mean too) Regards, -- Peter Xu From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34510) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fBzjQ-0002dM-Sv for qemu-devel@nongnu.org; Fri, 27 Apr 2018 05:31:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fBzjM-0007mO-BZ for qemu-devel@nongnu.org; Fri, 27 Apr 2018 05:31:56 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38244 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fBzjM-0007lq-7X for qemu-devel@nongnu.org; Fri, 27 Apr 2018 05:31:52 -0400 Date: Fri, 27 Apr 2018 17:31:35 +0800 From: Peter Xu Message-ID: <20180427093135.GC13269@xz-mi> References: <20180426091519.26934-1-xiaoguangrong@tencent.com> <32eaad8e-35a0-5240-37a2-4242b7890ab9@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH] migration: introduce decompress-error-check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong Cc: Eric Blake , pbonzini@redhat.com, mst@redhat.com, mtosatti@redhat.com, kvm@vger.kernel.org, Xiao Guangrong , qemu-devel@nongnu.org, dgilbert@redhat.com, wei.w.wang@intel.com, jiang.biao2@zte.com.cn On Fri, Apr 27, 2018 at 11:15:37AM +0800, Xiao Guangrong wrote: > > > On 04/26/2018 10:01 PM, Eric Blake wrote: > > On 04/26/2018 04:15 AM, guangrong.xiao@gmail.com wrote: > > > From: Xiao Guangrong > > > > > > QEMU 2.13 enables strict check for compression & decompression to > > > make the migration more robuster, that depends on the source to fix > > > > s/robuster/robust/ > > > > Will fix, thank you for pointing it out. > > > > the internal design which triggers the unexpected error conditions > > > > 2.13 hasn't been released yet. Why do we need a knob to explicitly turn > > off strict checking? Can we not instead make 2.13 automatically smart > > enough to tell if the incoming stream is coming from an older qemu > > (which might fail if the strict checks are enabled) vs. a newer qemu > > (the sender gave us what we need to ensure the strict checks are > > worthwhile)? > > > > Really smart. > > How about introduce a new command, MIG_CMD_DECOMPRESS_ERR_CHECK, > the destination will do strict check if got this command (i.e, new > QEMU is running on the source), otherwise, turn the check off. Why not we just introduce a compat bit for that? I mean something like: 15c3850325 ("migration: move skip_section_footers", 2017-06-28). Then we turn that check bit off for <=2.12. Would that work? (I would suspect that's what Eric mean too) Regards, -- Peter Xu