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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A92EEA8112 for ; Tue, 10 Feb 2026 13:13:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vpnY9-00086a-Hz; Tue, 10 Feb 2026 08:13:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vpnY1-000862-6I for qemu-devel@nongnu.org; Tue, 10 Feb 2026 08:12:59 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vpnXz-00054R-JB for qemu-devel@nongnu.org; Tue, 10 Feb 2026 08:12:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770729172; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=p72Ycd9HlgZa2McnyEkLgs5kf5rSxURidXNEjNx2Gzo=; b=W7Npmrqf0AYSUFjzAvndfxNagTyN1lSwA/cyqrbuLCInPmaImgPXdXPlT2g35E8/dNWdzN arrrDni3KnYQ/GGB79lXm98RCxBy5blsYe0D6SVi7I2cEwwRvjZI7eHskIh5FL7/HbKDdT AGgO6Ka5EYo5a09zwdRJDqwXDxQMlsU= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-678-FejE-XW1N-eKqgzskyzE6A-1; Tue, 10 Feb 2026 08:12:49 -0500 X-MC-Unique: FejE-XW1N-eKqgzskyzE6A-1 X-Mimecast-MFC-AGG-ID: FejE-XW1N-eKqgzskyzE6A_1770729167 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 21A191956067; Tue, 10 Feb 2026 13:12:47 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.253]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E1BA01956053; Tue, 10 Feb 2026 13:12:42 +0000 (UTC) Date: Tue, 10 Feb 2026 14:12:40 +0100 From: Kevin Wolf To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Paolo Bonzini , Yanan Wang , Zhao Liu , Qing Wang , Fam Zheng , Marcel Apfelbaum , Hannes Reinecke , pkrempa@redhat.com, Eduardo Habkost , Alberto Faria Subject: Re: [PATCH v3 0/5] scsi: persistent reservation live migration Message-ID: References: <20260129212035.219676-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260129212035.219676-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 29.01.2026 um 22:20 hat Stefan Hajnoczi geschrieben: > v3: > - Use warn_report_err() instead of suppressing errors [Daniel Berrangé] > - Wrap lines exceeding 80 characters > > v2: > - Add user documentation [Paolo] > - Send PREEMPT on the source if migration fails. This rollback operation > ensures the source regains access to the LUN even if migration fails after > the destination issues its own PREEMPT. > > Live migration does not work for SCSI Persistent Reservations acquired on > scsi-block devices. This patch series migrates the reservation key and > reservation type so that the destination QEMU can take over the persistent > reservation with the PREEMPT service action upon live migration. > > The approach involves snooping PERSISTENT RESERVE OUT replies and tracking the > scsi-block device's current reservation key and reservation type. In most cases > this involves no additional SCSI commands. This approach isn't perfect: if > another machine modifies the reservation on the physical LUN, then QEMU's state > becomes stale. Persistent reservations are inherently cooperative, so this is > acceptable as long as real applications don't run into problems. > > I am also working on a test suite called pr-tests that runs sg_persist(8) > commands across multiple machines in order to exercise various scenarios: > https://gitlab.com/stefanha/pr-tests On top of this, should we do something to catch cases where migrate-pr is off, but the user still tries to migrate while PRs are in use? Maybe have a migration blocker as long as pr_state->key is set? Kevin