From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,T_HK_NAME_DR,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D09B4C04E53 for ; Wed, 15 May 2019 09:39:58 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A375E2084F for ; Wed, 15 May 2019 09:39:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A375E2084F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:34215 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQqOD-00062d-Oh for qemu-devel@archiver.kernel.org; Wed, 15 May 2019 05:39:57 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55784) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQqN1-0005Ru-CT for qemu-devel@nongnu.org; Wed, 15 May 2019 05:38:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQqN0-0007Bb-Cx for qemu-devel@nongnu.org; Wed, 15 May 2019 05:38:43 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34720) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hQqN0-0007AP-5n for qemu-devel@nongnu.org; Wed, 15 May 2019 05:38:42 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2228B308421A; Wed, 15 May 2019 09:38:41 +0000 (UTC) Received: from work-vm (ovpn-117-193.ams2.redhat.com [10.36.117.193]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0E4A05D71F; Wed, 15 May 2019 09:38:39 +0000 (UTC) Date: Wed, 15 May 2019 10:38:37 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang Message-ID: <20190515093837.GD2668@work-vm> References: <20190424004700.12766-1-richardw.yang@linux.intel.com> <20190424004700.12766-3-richardw.yang@linux.intel.com> <0eb5e5a5-593e-f4a2-7e2d-a9fed481ab6c@gmail.com> <20190426005133.GB25513@richard> <20190514151813.GL2753@work-vm> <20190515063827.GB11845@richard> <20190515070341.GA24741@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190515070341.GA24741@richard> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Wed, 15 May 2019 09:38:41 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH 2/4] migration/savevm: use migration_is_blocked to validate X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Henrique Barboza , qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > On Wed, May 15, 2019 at 02:38:27PM +0800, Wei Yang wrote: > >On Tue, May 14, 2019 at 04:18:14PM +0100, Dr. David Alan Gilbert wrote: > >>* Wei Yang (richardw.yang@linux.intel.com) wrote: > >>> > >>> Well, when you look into the source side of migration: > >>> > >>> qmp_migrate > >>> migrate_prepare > >>> migration_is_blocked > >>> > >>> This means if migration_is_blocked fails, the source will not start migration. > >>> And it is the same as save_snapshot. > >>> > >>> From my understanding, when we load a vm, it should check the same > >>> requirement. > >> > >>I've been thinking about this, and I think I agree with Daniel on this. > >>The 'migration_blockers' list tells you that something about the > >>*current* state of a device means that it can't be migrated - e.g. > >>a 9pfs with a mounted filesystem can't be migrated. > >> > >>If we're about to reload the state from a snapshot, then the saved > >>snapshot's state must have been migratable, so that's OK. > >> > > > >The situation is on a vm with 'migration_blockers' still could reload from a > >snapshot. > > > >This sounds reasonable. Thanks :-) > > > > Well, this is still a little strange. The means source vm and destination vm > could have different configuration. Is this common? It's not different configuration that I'm worried about here; but it's different runtime state. Items can get added/removed from migration_blockers dynamically depending on the behaviour of the guest; e.g. a device might only migratable in certain states. Dave > -- > Wei Yang > Help you, Help me -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK