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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 E13FCC04AAF for ; Tue, 21 May 2019 09:35:04 +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 BA6AF21743 for ; Tue, 21 May 2019 09:35:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BA6AF21743 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]:50116 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hT1Al-0004cY-4C for qemu-devel@archiver.kernel.org; Tue, 21 May 2019 05:35:03 -0400 Received: from eggs.gnu.org ([209.51.188.92]:39808) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hT19f-00044k-LP for qemu-devel@nongnu.org; Tue, 21 May 2019 05:33:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hT19e-0001Rr-NE for qemu-devel@nongnu.org; Tue, 21 May 2019 05:33:55 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44242) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hT19e-0001NJ-Hv for qemu-devel@nongnu.org; Tue, 21 May 2019 05:33:54 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1AF965AFD9 for ; Tue, 21 May 2019 09:33:48 +0000 (UTC) Received: from work-vm (ovpn-117-210.ams2.redhat.com [10.36.117.210]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 298F45C269; Tue, 21 May 2019 09:33:38 +0000 (UTC) Date: Tue, 21 May 2019 10:33:36 +0100 From: "Dr. David Alan Gilbert" To: Jens Freimann Message-ID: <20190521093336.GA2915@work-vm> References: <20190517125820.2885-1-jfreimann@redhat.com> <20190517125820.2885-2-jfreimann@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190517125820.2885-2-jfreimann@redhat.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Tue, 21 May 2019 09:33:49 +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 1/4] migration: allow unplug during migration for failover devices 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: pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, mst@redhat.com, aadam@redhat.com, qemu-devel@nongnu.org, laine@redhat.com, ailan@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Jens Freimann (jfreimann@redhat.com) wrote: > In "b06424de62 migration: Disable hotplug/unplug during migration" we > added a check to disable unplug for all devices until we have figured > out what works. For failover primary devices qdev_unplug() is called > from the migration handler, i.e. during migration. > > This patch adds a flag to DeviceState which is set to false for all > devices and makes an exception for vfio-pci devices that are also > primary devices in a failover pair. > > Signed-off-by: Jens Freimann So I think this is safe in your case, because you trigger the unplug right at the start of migration during setup and plug after failure; however it's not generally safe - I can't unplug a device while the migration is actually in progress. Dave > --- > hw/core/qdev.c | 1 + > include/hw/qdev-core.h | 1 + > qdev-monitor.c | 2 +- > 3 files changed, 3 insertions(+), 1 deletion(-) > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > index f9b6efe509..98cdaa6bf7 100644 > --- a/hw/core/qdev.c > +++ b/hw/core/qdev.c > @@ -954,6 +954,7 @@ static void device_initfn(Object *obj) > > dev->instance_id_alias = -1; > dev->realized = false; > + dev->allow_unplug_during_migration = false; > > object_property_add_bool(obj, "realized", > device_get_realized, device_set_realized, NULL); > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h > index 33ed3b8dde..5437395779 100644 > --- a/include/hw/qdev-core.h > +++ b/include/hw/qdev-core.h > @@ -146,6 +146,7 @@ struct DeviceState { > bool pending_deleted_event; > QemuOpts *opts; > int hotplugged; > + bool allow_unplug_during_migration; > BusState *parent_bus; > QLIST_HEAD(, NamedGPIOList) gpios; > QLIST_HEAD(, BusState) child_bus; > diff --git a/qdev-monitor.c b/qdev-monitor.c > index 373b9ad445..9cce8b93c2 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -867,7 +867,7 @@ void qdev_unplug(DeviceState *dev, Error **errp) > return; > } > > - if (!migration_is_idle()) { > + if (!migration_is_idle() && !dev->allow_unplug_during_migration) { > error_setg(errp, "device_del not allowed while migrating"); > return; > } > -- > 2.21.0 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK