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 732ECE95396 for ; Wed, 4 Feb 2026 13:16:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vnck6-00087w-7q; Wed, 04 Feb 2026 08:16:26 -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 1vncjw-00084i-Uj for qemu-devel@nongnu.org; Wed, 04 Feb 2026 08:16:24 -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 1vncjp-00017r-Sa for qemu-devel@nongnu.org; Wed, 04 Feb 2026 08:16:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770210968; 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: in-reply-to:in-reply-to:references:references; bh=A2VEJb8N1dPg3t1FRCvYZ2PFOYUkhFcDLv0JhHTU5AQ=; b=QvaicRYxTZNozv9+BJqRhLDuVTjYNGGsQgjfo6k7+FQfL6xM1QEE/aU+oNSmEk0ApRcBEy 3zNtTQPssCY2O+xScZsz7ik2T3ohnoPf6zz5OBQlyEkrs2QJIWMAd4wYsXRCdPicvATZUZ 0485VYKILen/sA7J/BaqgrbTGeKZa1A= 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-660-wh9ZBhHFObOhdFqzys1nxw-1; Wed, 04 Feb 2026 08:16:05 -0500 X-MC-Unique: wh9ZBhHFObOhdFqzys1nxw-1 X-Mimecast-MFC-AGG-ID: wh9ZBhHFObOhdFqzys1nxw_1770210964 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 C4AFF1956051; Wed, 4 Feb 2026 13:16:03 +0000 (UTC) Received: from localhost (unknown [10.2.16.22]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 032B31800464; Wed, 4 Feb 2026 13:16:02 +0000 (UTC) Date: Wed, 4 Feb 2026 08:16:02 -0500 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Paolo Bonzini , Yanan Wang , Zhao Liu , Qing Wang , Kevin Wolf , Fam Zheng , Marcel Apfelbaum , Hannes Reinecke , pkrempa@redhat.com, Eduardo Habkost , Alberto Faria , berrange@redhat.com Subject: Re: [PATCH v3 0/5] scsi: persistent reservation live migration Message-ID: <20260204131602.GB591743@fedora> References: <20260129212035.219676-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hUE8l+RUprBjQyXP" Content-Disposition: inline In-Reply-To: <20260129212035.219676-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@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=unavailable 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 --hUE8l+RUprBjQyXP Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 29, 2026 at 04:20:30PM -0500, Stefan Hajnoczi wrote: > v3: > - Use warn_report_err() instead of suppressing errors [Daniel Berrang=E9] > - Wrap lines exceeding 80 characters CCing Daniel Berrang=E9 (sorry, I forgot!) >=20 > 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 af= ter > the destination issues its own PREEMPT. >=20 > 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. >=20 > The approach involves snooping PERSISTENT RESERVE OUT replies and trackin= g 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 thi= s is > acceptable as long as real applications don't run into problems. >=20 > 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 >=20 > Stefan Hajnoczi (5): > scsi: generalize scsi_SG_IO_FROM_DEV() to scsi_SG_IO() > scsi: add error reporting to scsi_SG_IO() > scsi: track SCSI reservation state for live migration > scsi: save/load SCSI reservation state > docs: add SCSI migrate-pr documentation >=20 > docs/system/device-emulation.rst | 1 + > docs/system/devices/scsi/index.rst | 10 + > docs/system/devices/scsi/migrate-pr.rst | 54 +++++ > include/hw/scsi/scsi.h | 15 +- > include/scsi/constants.h | 21 ++ > hw/core/machine.c | 4 +- > hw/scsi/scsi-bus.c | 3 + > hw/scsi/scsi-disk.c | 90 +++++++- > hw/scsi/scsi-generic.c | 291 +++++++++++++++++++++++- > hw/scsi/trace-events | 2 + > 10 files changed, 476 insertions(+), 15 deletions(-) > create mode 100644 docs/system/devices/scsi/index.rst > create mode 100644 docs/system/devices/scsi/migrate-pr.rst >=20 > --=20 > 2.52.0 >=20 --hUE8l+RUprBjQyXP Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmmDRpEACgkQnKSrs4Gr c8gzRwf/b1eqPwjmM1IjisMIPLVd+lh2DYuSDA5T0UctUO85dBOvzd5m6LD2qGxm 8KTzB1Rw9mepqsl+2q5Fqw1zMJ8+xoP1Ql18ruKrWjwXVFJXGFXQhgs0TsaXU0t4 1O1Eskym1ccPUNmoWbeZwrCWt/59QwU6d7USnz5IiIZ2HBpRYPMoHW7Q4Ao8KDsA LY3E7RPMtVWfJUH3TGigMzCjnz5PPmJ0tbM9cqMlp5wqIA7DFZlin6j1CJ+0iSYU C718KFe58OvjgZNw+7S7jD+zQA0tfWnLqfXOn3jWmo8/fRTZ78351t+sEmA6WuVG Emzv5RF9UpwjtI697maApjTXu51O2g== =8JEL -----END PGP SIGNATURE----- --hUE8l+RUprBjQyXP--