From patchwork Fri Oct 18 20:20:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Freimann X-Patchwork-Id: 11199551 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3917214ED for ; Fri, 18 Oct 2019 20:21:54 +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 090BE2082C for ; Fri, 18 Oct 2019 20:21:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 090BE2082C 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:45742 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLYky-0006oX-UL for patchwork-qemu-devel@patchwork.kernel.org; Fri, 18 Oct 2019 16:21:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48027) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLYk6-0005bR-34 for qemu-devel@nongnu.org; Fri, 18 Oct 2019 16:21:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLYk3-0005ZK-45 for qemu-devel@nongnu.org; Fri, 18 Oct 2019 16:20:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42830) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLYk2-0005WB-KH for qemu-devel@nongnu.org; Fri, 18 Oct 2019 16:20:54 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4B83510F2E83; Fri, 18 Oct 2019 20:20:51 +0000 (UTC) Received: from localhost (ovpn-116-92.ams2.redhat.com [10.36.116.92]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 83E5860600; Fri, 18 Oct 2019 20:20:42 +0000 (UTC) From: Jens Freimann To: qemu-devel@nongnu.org Subject: [PATCH v4 0/11] add failover feature for assigned network devices Date: Fri, 18 Oct 2019 22:20:29 +0200 Message-Id: <20191018202040.30349-1-jfreimann@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.66]); Fri, 18 Oct 2019 20:20:51 +0000 (UTC) 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: pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, mst@redhat.com, aadam@redhat.com, dgilbert@redhat.com, alex.williamson@redhat.com, laine@redhat.com, ailan@redhat.com, parav@mellanox.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" This is implementing the host side of the net_failover concept (https://www.kernel.org/doc/html/latest/networking/net_failover.html) Changes since v3: * Patch 1, make return values of qdev_should_hide_device() more clear * Patch 1, clarify comment about new should_be_hidden DeviceListener * Patch 2 new patch, add net_failover_option_id to PCIDevice, only allow PCIExpress devices for now * Patch 8, only go into wait_unplug state when failover devices are present * Patch 8, add new state to migration_is_setup_or_active, tested cancelling while migration is in this state * Patch 8, simplify handling of wait_unplug state, don't cancel migration after timeout, let upper layer do this, get rid of retry counter (dgilbert) * Patch 11, move net_failover_pair_id to PCIDev, move check for pci class to PCI code, only allow PCIe devices for now as we only support hotplugging these devices (aw) * verified qemu make check tests ran, checked that docker-test-quick@centos7 runs successful, tested migration with/without failover, without vfio-pci * this now allows only PCIe devices because that's the only hotplug controller that supports the partial unplug as of now. I'll work on making it discoverable for libvirt or on support for the other hotplug controllers in a follow-on patch set 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/ 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,net_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 (10): qdev/qbus: add hidden device support 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 hw/core/qdev.c | 20 +++ hw/net/virtio-net.c | 267 +++++++++++++++++++++++++++++++++ hw/pci/pci.c | 2 + hw/pci/pcie.c | 6 + hw/vfio/pci.c | 35 ++++- hw/vfio/pci.h | 2 + include/hw/pci/pci.h | 1 + include/hw/qdev-core.h | 10 ++ include/hw/virtio/virtio-net.h | 12 ++ include/hw/virtio/virtio.h | 1 + include/migration/vmstate.h | 2 + migration/migration.c | 34 +++++ migration/migration.h | 3 + migration/savevm.c | 36 +++++ migration/savevm.h | 1 + qapi/migration.json | 24 ++- qapi/net.json | 16 ++ qdev-monitor.c | 43 +++++- tests/libqos/libqos.c | 3 +- vl.c | 6 +- 20 files changed, 515 insertions(+), 9 deletions(-)