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=-0.5 required=3.0 tests=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 A704FCA9EA0 for ; Fri, 25 Oct 2019 12:23:18 +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 720F82084C for ; Fri, 25 Oct 2019 12:23:18 +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="QUsI8uJ+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 720F82084C 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]:59288 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNyce-0000Sq-BU for qemu-devel@archiver.kernel.org; Fri, 25 Oct 2019 08:23:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50328) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNyZN-0002qW-TN for qemu-devel@nongnu.org; Fri, 25 Oct 2019 08:19:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iNyZK-0006t8-G5 for qemu-devel@nongnu.org; Fri, 25 Oct 2019 08:19:52 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:21627 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iNyZH-0006qo-95 for qemu-devel@nongnu.org; Fri, 25 Oct 2019 08:19:48 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1572005985; 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=Y/yIDQXOujy2p/+kmEGN3cjeFHHU24zUh36N/pe1xyE=; b=QUsI8uJ+2ejW3YB7htIkdeGkXzmNkN8v3tLhnbULCNFb66sb6lzL+J2YxZPXZLZJhw2EC1 fw55mrIwTKo7gSls+luymksP+b8wwCkMAM7uK+Ag4SCMLuhyA1/gWr+kJbR+YByaWyW8JS ii4AzuU120+5eYkigypMBR6yShya9JE= 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-24-bJVFGKTyNb6IgmfByamkRA-1; Fri, 25 Oct 2019 08:19:41 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9F4051800E01; Fri, 25 Oct 2019 12:19:40 +0000 (UTC) Received: from localhost (ovpn-117-235.ams2.redhat.com [10.36.117.235]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4229E60BEC; Fri, 25 Oct 2019 12:19:32 +0000 (UTC) From: Jens Freimann To: qemu-devel@nongnu.org Subject: [PATCH v6 0/11] add failover feature for assigned network devices Date: Fri, 25 Oct 2019 14:19:19 +0200 Message-Id: <20191025121930.6855-1-jfreimann@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: bJVFGKTyNb6IgmfByamkRA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.61 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, jasowang@redhat.com, dgilbert@redhat.com, armbru@redhat.com, alex.williamson@redhat.com, laine@redhat.com, ailan@redhat.com, parav@mellanox.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.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 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=20 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. Wh= en 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 s= lot 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 QE= MU 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=3Dsplit -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=3Droot0,multifunction=3Don,chassis=3D0,ad= dr=3D0xa \ -device pcie-root-port,id=3Droot1,bus=3Dpcie.0,chassis=3D1 \ -device pcie-root-port,id=3Droot2,bus=3Dpcie.0,chassis=3D2 \ -netdev tap,script=3D/root/bin/bridge.sh,downscript=3Dno,id=3Dhostn= et1,vhost=3Don \ -device virtio-net-pci,netdev=3Dhostnet1,id=3Dnet1,mac=3D52:54:00:6= f:55:cc,bus=3Droot2,failover=3Don \ =09-device vfio-pci,host=3D5e:00.2,id=3Dhostdev0,bus=3Droot1,failover_pair_= id =3Dnet1 \ /root/rhel-guest-image-8.0-1781.x86_64.qcow2 I'm grateful for any remarks or ideas! Thanks! regards, Jens=20 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 --=20 2.21.0