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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 2D7E5C4363C for ; Thu, 8 Oct 2020 15:53:40 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 95D55206F7 for ; Thu, 8 Oct 2020 15:53:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Mu0H5D6G" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95D55206F7 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 ([::1]:47824 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kQYEc-0001xu-IT for qemu-devel@archiver.kernel.org; Thu, 08 Oct 2020 11:53:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58456) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kQYBf-0006cS-1o for qemu-devel@nongnu.org; Thu, 08 Oct 2020 11:50:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:28622) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kQYBa-0002cP-Nv for qemu-devel@nongnu.org; Thu, 08 Oct 2020 11:50:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602172230; 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; bh=s1woty3NW0yTXYnh6x7CtUrcLpPLI4XsLMjwMq0zmN8=; b=Mu0H5D6GerOjCCJeFNzv/6nnXnyDRvrInZDDRXz8lWnmFEO6AER/skRKdr/Pet0zC5D9Le igJnbEoFuAqGbJnfmTpNbRwt0khGVYv1xF/p4gaeN3vh945WXA6J5zv/pqNVKvbgTlsDh/ 0Axyyi0NIsQCC5DDESzoQTc2OyARf7M= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-217-H5hI6rY1OBCccRz89G6p3w-1; Thu, 08 Oct 2020 11:50:26 -0400 X-MC-Unique: H5hI6rY1OBCccRz89G6p3w-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 616DB803F5A; Thu, 8 Oct 2020 15:50:06 +0000 (UTC) Received: from localhost.localdomain.com (unknown [10.36.110.13]) by smtp.corp.redhat.com (Postfix) with ESMTP id 71EE25C1BD; Thu, 8 Oct 2020 15:50:02 +0000 (UTC) From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH v6 00/10] migration: bring improved savevm/loadvm/delvm to QMP Date: Thu, 8 Oct 2020 16:49:51 +0100 Message-Id: <20201008155001.3357288-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/08 02:56:27 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Peter Krempa , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , "Denis V. Lunev" , qemu-block@nongnu.org, Juan Quintela , John Snow , Markus Armbruster , Max Reitz , Pavel Dovgalyuk , Paolo Bonzini , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" v1: https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg00866.html=0D v2: https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg07523.html=0D v3: https://lists.gnu.org/archive/html/qemu-devel/2020-08/msg07076.html=0D v4: https://lists.gnu.org/archive/html/qemu-devel/2020-09/msg05221.html=0D v5: https://lists.gnu.org/archive/html/qemu-devel/2020-10/msg00587.html=0D =0D This series aims to provide a better designed replacement for the=0D savevm/loadvm/delvm HMP commands, which despite their flaws continue=0D to be actively used in the QMP world via the HMP command passthrough=0D facility.=0D =0D The main problems addressed are:=0D =0D - The logic to pick which disk to store the vmstate in is not=0D satsifactory.=0D =0D The first block driver state cannot be assumed to be the root disk=0D image, it might be OVMF varstore and we don't want to store vmstate=0D in there.=0D =0D - The logic to decide which disks must be snapshotted is hardwired=0D to all disks which are writable=0D =0D Again with OVMF there might be a writable varstore, but this can be=0D raw rather than qcow2 format, and thus unable to be snapshotted.=0D While users might wish to snapshot their varstore, in some/many/most=0D cases it is entirely uneccessary. Users are blocked from snapshotting=0D their VM though due to this varstore.=0D =0D - The commands are synchronous blocking execution and returning=0D errors immediately.=0D =0D This is partially addressed by integrating with the job framework.=0D This forces the client to use the async commands to determine=0D the completion status or error message from the operations.=0D =0D In the block code I've only dealt with node names for block devices, as=0D IIUC, this is all that libvirt should need in the -blockdev world it now=0D lives in. IOW, I've made not attempt to cope with people wanting to use=0D these QMP commands in combination with -drive args, as libvirt will=0D never use -drive with a QEMU new enough to have these new commands.=0D =0D The main limitations of this current impl=0D =0D - The snapshot process runs serialized in the main thread. ie QEMU=0D guest execution is blocked for the duration. The job framework=0D lets us fix this in future without changing the QMP semantics=0D exposed to the apps.=0D =0D - Most vmstate loading errors just go to stderr, as they are not=0D using Error **errp reporting. Thus the job framework just=0D reports a fairly generic message=0D =0D "Error -22 while loading VM state"=0D =0D Again this can be fixed later without changing the QMP semantics=0D exposed to apps.=0D =0D I've done some minimal work in libvirt to start to make use of the new=0D commands to validate their functionality, but this isn't finished yet.=0D =0D My ultimate goal is to make the GNOME Boxes maintainer happy again by=0D having internal snapshots work with OVMF:=0D =0D https://gitlab.gnome.org/GNOME/gnome-boxes/-/commit/c486da262f6566326fbcb= 5e=3D=0D f45c5f64048f16a6e=0D =0D Changed in v6:=0D =0D - Resolve many conflicts with recent replay changes=0D - Misc typos in QAPI=0D =0D Changed in v5:=0D =0D - Fix prevention of tag overwriting=0D - Refactor and expand test suite coverage to validate=0D more negative scenarios=0D =0D Changed in v4:=0D =0D - Make the device lists mandatory, dropping all support for=0D QEMU's built-in heuristics to select devices.=0D =0D - Improve some error reporting and I/O test coverage=0D =0D Changed in v3:=0D =0D - Schedule a bottom half to escape from coroutine context in=0D the jobs. This is needed because the locking in the snapshot=0D code goes horribly wrong when run from a background coroutine=0D instead of the main event thread.=0D =0D - Re-factor way we iterate over devices, so that we correctly=0D report non-existant devices passed by the user over QMP.=0D =0D - Add QAPI docs notes about limitations wrt vmstate error=0D reporting (it all goes to stderr not an Error **errp)=0D so QMP only gets a fairly generic error message currently.=0D =0D - Add I/O test to validate many usage scenarios / errors=0D =0D - Add I/O test helpers to handle QMP events with a deterministic=0D ordering=0D =0D - Ensure 'delete-snapshot' reports an error if requesting=0D delete from devices that don't support snapshot, instead of=0D silently succeeding with no erro.=0D =0D Changed in v2:=0D =0D - Use new command names "snapshot-{load,save,delete}" to make it=0D clear that these are different from the "savevm|loadvm|delvm"=0D as they use the Job framework=0D =0D - Use an include list for block devs, not an exclude list=0D =0D Daniel P. Berrang=3DC3=3DA9 (10):=0D block: push error reporting into bdrv_all_*_snapshot functions=0D migration: stop returning errno from load_snapshot()=0D block: add ability to specify list of blockdevs during snapshot=0D block: allow specifying name of block device for vmstate storage=0D block: rename and alter bdrv_all_find_snapshot semantics=0D migration: control whether snapshots are ovewritten=0D migration: wire up support for snapshot device selection=0D migration: introduce a delete_snapshot wrapper=0D iotests: add support for capturing and matching QMP events=0D migration: introduce snapshot-{save,load,delete} QMP commands=0D =0D block/monitor/block-hmp-cmds.c | 7 +-=0D block/snapshot.c | 256 +++++++++++++++------=0D include/block/snapshot.h | 23 +-=0D include/migration/snapshot.h | 14 +-=0D migration/savevm.c | 280 ++++++++++++++++++++---=0D monitor/hmp-cmds.c | 12 +-=0D qapi/job.json | 9 +-=0D qapi/migration.json | 121 ++++++++++=0D replay/replay-debugging.c | 12 +-=0D replay/replay-snapshot.c | 5 +-=0D softmmu/vl.c | 2 +-=0D tests/qemu-iotests/267.out | 12 +-=0D tests/qemu-iotests/310 | 385 +++++++++++++++++++++++++++++++=0D tests/qemu-iotests/310.out | 407 +++++++++++++++++++++++++++++++++=0D tests/qemu-iotests/common.qemu | 107 ++++++++-=0D tests/qemu-iotests/group | 1 +=0D 16 files changed, 1508 insertions(+), 145 deletions(-)=0D create mode 100755 tests/qemu-iotests/310=0D create mode 100644 tests/qemu-iotests/310.out=0D =0D --=3D20=0D 2.26.2=0D =0D