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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B6725CA9EC0 for ; Mon, 28 Oct 2019 16:59:18 +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 8F38E208C0 for ; Mon, 28 Oct 2019 16:59:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F38E208C0 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]:60710 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP8MP-0001WT-Gq for qemu-devel@archiver.kernel.org; Mon, 28 Oct 2019 12:59:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35095) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP7QB-0006QP-LD for qemu-devel@nongnu.org; Mon, 28 Oct 2019 11:59:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iP7Q8-0004EB-A5 for qemu-devel@nongnu.org; Mon, 28 Oct 2019 11:59:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:28580) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iP7Q6-0004BQ-2F for qemu-devel@nongnu.org; Mon, 28 Oct 2019 11:59:04 -0400 Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1250D8553D for ; Mon, 28 Oct 2019 15:59:00 +0000 (UTC) Received: by mail-qk1-f197.google.com with SMTP id a13so8283410qkc.17 for ; Mon, 28 Oct 2019 08:59:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=nMWAnY6McylHcGTvc+B7VrN+HbqR4plgo+YW/WXOm7U=; b=rMIe3RXUlfUKB5gWBC6s80CMv7OhFzIM4Xj7uPFOqS6GZLf9rNtuOV6fZQs+YECS11 nN36oFR1pMBnlY4eCLDZY8C3kH5ZXyb3Nqq7TNg1lDiuhSQuiIx4tWJmbvVlskRBjvjV DE2ZHVPfCP82Wov2Cyud+iUZfmu9fySOHzWkUzv/bZe+lchFjKyDhG0O469UGlROqsLR Rht51I0NSGgyXvjbExxg86AjuciWOzectyVVDH3UvrgfcwYQ0BnWdDG3+gKKhHmblUAx zrJz04qD5V+5y8Ovf5aEHnQPgV3HCB9lBwQvmdgAHsJwz3vdsxPaf+vO3wNZMGOF2c1B OZrw== X-Gm-Message-State: APjAAAVaQyw05X3ttBmWLj+hycxnh9vGFcR2Uvqr97iWTr+/hF22T84d gujkJ7JVen3RZVh2yjCjLpO3V/YWoQSIx8W7MMP7H6To2lAG0e0268G+ynOuCoCX3g5DTQa7a5z 0iiNrUDMuBfEXeTY= X-Received: by 2002:ad4:4d0f:: with SMTP id l15mr10957615qvl.78.1572278339206; Mon, 28 Oct 2019 08:58:59 -0700 (PDT) X-Google-Smtp-Source: APXvYqyAA1G0s1q3mJXZBoSh/sGMoKtLIOdn/XR+t4enawzGwyaheI0aXNVp2rMIuY7bYzWyYYAKzQ== X-Received: by 2002:ad4:4d0f:: with SMTP id l15mr10957589qvl.78.1572278338811; Mon, 28 Oct 2019 08:58:58 -0700 (PDT) Received: from redhat.com (bzq-79-176-10-77.red.bezeqint.net. [79.176.10.77]) by smtp.gmail.com with ESMTPSA id r2sm7522266qtc.28.2019.10.28.08.58.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Oct 2019 08:58:58 -0700 (PDT) Date: Mon, 28 Oct 2019 11:58:53 -0400 From: "Michael S. Tsirkin" To: Jens Freimann Subject: Re: [PATCH v6 0/11] add failover feature for assigned network devices Message-ID: <20191028115750-mutt-send-email-mst@kernel.org> References: <20191025121930.6855-1-jfreimann@redhat.com> <20191028102723.jwfzxp6mav6ce62g@jenstp.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191028102723.jwfzxp6mav6ce62g@jenstp.localdomain> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: aadam@redhat.com, ailan@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" I see at least comments from Markus. You answered but don't you need to also tweak the patch? On Mon, Oct 28, 2019 at 11:27:23AM +0100, Jens Freimann wrote: > Hi Michael, > > I addressed all comments and feedback and think this can be merged but > I'm unclear about which tree it should go to. Will you merge it into > the virtio-tree? > > regards, > Jens > > On Fri, Oct 25, 2019 at 02:19:19PM +0200, Jens Freimann wrote: > > This is implementing the host side of the net_failover concept > > (https://www.kernel.org/doc/html/latest/networking/net_failover.html) > > > > Changes since v5: > > * rename net_failover_pair_id parameter/property to failover_pair_id > > * in PCI code use pci_bus_is_express(). This won't fail on functions > 0 > > * make sure primary and standby can't be added to same PCI slot > > * add documentation file in docs/ to virtio-net patch, add file to > > MAINTAINERS (added to networking devices section) > > * add comment to QAPI event for failover negotiation, try to improve > > commit message > > > > The general idea is that we have a pair of devices, a vfio-pci and a > > virtio-net device. Before migration the vfio device is unplugged and data > > flows to the virtio-net device, on the target side another vfio-pci device > > is plugged in to take over the data-path. In the guest the net_failover > > module will pair net devices with the same MAC address. > > > > * Patch 1 adds the infrastructure to hide the device for the qbus and qdev APIs > > > > * Patch 2 adds checks to PCIDevice for only allowing ethernet devices as > > failover primary and only PCIExpress capable devices > > > > * Patch 3 sets a new flag for PCIDevice 'partially_hotplugged' which we > > use to skip the unrealize code path when doing a unplug of the primary > > device > > > > * Patch 4 sets the pending_deleted_event before triggering the guest > > unplug request > > > > * Patch 5 and 6 add new qmp events, one sends the device id of a device > > that was just requested to be unplugged from the guest and another one > > to let libvirt know if VIRTIO_NET_F_STANDBY was negotiated > > > > * Patch 7 make sure that we can unplug the vfio-device before > > migration starts > > > > * Patch 8 adds a new migration state that is entered while we wait for > > devices to be unplugged by guest OS > > > > * Patch 9 just adds the new migration state to a check in libqos code > > > > * Patch 10 In the second patch the virtio-net uses the API to defer adding the vfio > > device until the VIRTIO_NET_F_STANDBY feature is acked. It also > > implements the migration handler to unplug the device from the guest and > > re-plug in case of migration failure > > > > * Patch 11 allows migration for failover vfio-pci devices > > > > Previous discussion: > > RFC v1 https://patchwork.ozlabs.org/cover/989098/ > > RFC v2 https://www.mail-archive.com/qemu-devel@nongnu.org/msg606906.html > > v1: https://lists.gnu.org/archive/html/qemu-devel/2019-05/msg03968.html > > v2: https://www.mail-archive.com/qemu-devel@nongnu.org/msg635214.html > > v3: https://patchew.org/QEMU/20191011112015.11785-1-jfreimann@redhat.com/ > > v4: https://patchew.org/QEMU/20191018202040.30349-1-jfreimann@redhat.com/ > > v5: https://patchew.org/QEMU/20191023082711.16694-1-jfreimann@redhat.com/ > > > > To summarize concerns/feedback from previous discussion: > > 1.- guest OS can reject or worse _delay_ unplug by any amount of time. > > Migration might get stuck for unpredictable time with unclear reason. > > This approach combines two tricky things, hot/unplug and migration. > > -> We need to let libvirt know what's happening. Add new qmp events > > and a new migration state. When a primary device is (partially) > > unplugged (only from guest) we send a qmp event with the device id. When > > it is unplugged from the guest the DEVICE_DELETED event is sent. > > Migration will enter the wait-unplug state while waiting for the guest > > os to unplug all primary devices and then move on with migration. > > 2. PCI devices are a precious ressource. The primary device should never > > be added to QEMU if it won't be used by guest instead of hiding it in > > QEMU. > > -> We only hotplug the device when the standby feature bit was > > negotiated. We save the device cmdline options until we need it for > > qdev_device_add() > > Hiding a device can be a useful concept to model. For example a > > pci device in a powered-off slot could be marked as hidden until the slot is > > powered on (mst). > > 3. Management layer software should handle this. Open Stack already has > > components/code to handle unplug/replug VFIO devices and metadata to > > provide to the guest for detecting which devices should be paired. > > -> An approach that includes all software from firmware to > > higher-level management software wasn't tried in the last years. This is > > an attempt to keep it simple and contained in QEMU as much as possible. > > One of the problems that stopped management software and libvirt from > > implementing this idea is that it can't be sure that it's possible to > > re-plug the primary device. By not freeing the devices resources in QEMU > > and only asking the guest OS to unplug it is possible to re-plug the > > device in case of a migration failure. > > 4. Hotplugging a device and then making it part of a failover setup is > > not possible > > -> addressed by extending qdev hotplug functions to check for hidden > > attribute, so e.g. device_add can be used to plug a device. > > > > > > I have tested this with a mlx5 and igb NIC and was able to migrate the VM. > > > > Command line example: > > > > qemu-system-x86_64 -enable-kvm -m 3072 -smp 3 \ > > -machine q35,kernel-irqchip=split -cpu host \ > > -serial stdio \ > > -net none \ > > -qmp unix:/tmp/qmp.socket,server,nowait \ > > -monitor telnet:127.0.0.1:5555,server,nowait \ > > -device pcie-root-port,id=root0,multifunction=on,chassis=0,addr=0xa \ > > -device pcie-root-port,id=root1,bus=pcie.0,chassis=1 \ > > -device pcie-root-port,id=root2,bus=pcie.0,chassis=2 \ > > -netdev tap,script=/root/bin/bridge.sh,downscript=no,id=hostnet1,vhost=on \ > > -device virtio-net-pci,netdev=hostnet1,id=net1,mac=52:54:00:6f:55:cc,bus=root2,failover=on \ > > -device vfio-pci,host=5e:00.2,id=hostdev0,bus=root1,failover_pair_id =net1 \ > > /root/rhel-guest-image-8.0-1781.x86_64.qcow2 > > > > I'm grateful for any remarks or ideas! > > > > Thanks! > > > > regards, > > Jens > > > > > > Jens Freimann (11): > > qdev/qbus: add hidden device support > > pci: add option for net failover > > pci: mark devices partially unplugged > > pci: mark device having guest unplug request pending > > qapi: add unplug primary event > > qapi: add failover negotiated event > > migration: allow unplug during migration for failover devices > > migration: add new migration state wait-unplug > > libqos: tolerate wait-unplug migration state > > net/virtio: add failover support > > vfio: unplug failover primary device before migration > > > > MAINTAINERS | 1 + > > docs/virtio-net-failover.rst | 68 ++++++++ > > hw/core/qdev.c | 25 +++ > > hw/net/virtio-net.c | 302 +++++++++++++++++++++++++++++++++ > > hw/pci/pci.c | 32 ++++ > > hw/pci/pcie.c | 6 + > > hw/vfio/pci.c | 26 ++- > > hw/vfio/pci.h | 1 + > > include/hw/pci/pci.h | 4 + > > include/hw/qdev-core.h | 30 ++++ > > include/hw/virtio/virtio-net.h | 12 ++ > > include/hw/virtio/virtio.h | 1 + > > include/migration/vmstate.h | 2 + > > migration/migration.c | 21 +++ > > migration/migration.h | 3 + > > migration/savevm.c | 36 ++++ > > migration/savevm.h | 2 + > > qapi/migration.json | 24 ++- > > qapi/net.json | 19 +++ > > qdev-monitor.c | 43 ++++- > > tests/libqos/libqos.c | 3 +- > > vl.c | 6 +- > > 22 files changed, 652 insertions(+), 15 deletions(-) > > create mode 100644 docs/virtio-net-failover.rst > > > > -- > > 2.21.0 > > > > > >