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 68C90C4345F for ; Tue, 30 Apr 2024 08:20:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s1iiO-0007Wf-7q; Tue, 30 Apr 2024 04:19:52 -0400 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 1s1iiG-0007QM-Lk for qemu-devel@nongnu.org; Tue, 30 Apr 2024 04:19:46 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1s1iiC-0002Wh-KM for qemu-devel@nongnu.org; Tue, 30 Apr 2024 04:19:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714465180; 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=uO//olb4+eASICal0010LBnYnskJaQvOgDr4LIleKfs=; b=E1z9YB267jFcapVchoFo25VAJ0MCTopA24WHFBQ8sSAXqnypUKe0AJSWb5qyFsY5NXYiy0 AhJMBu+8VGH+EjnzlGa3HvqxGNyTCXTLdGPcYuvMfyFOeOvb6DCMkHm5h36Sy6Wgdddn8K ZDqdBD83ytb3uJZty+T/pRRjXFZHR74= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-531-8VqLkmUAOoSZtDuMOZM0RA-1; Tue, 30 Apr 2024 04:19:35 -0400 X-MC-Unique: 8VqLkmUAOoSZtDuMOZM0RA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id A044F18065B2; Tue, 30 Apr 2024 08:19:34 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4C41840C6DAE; Tue, 30 Apr 2024 08:19:34 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7097B21E66C8; Tue, 30 Apr 2024 10:19:33 +0200 (CEST) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Cc: qemu-block@nongnu.org, raphael@enfabrica.net, mst@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, eblake@redhat.com, eduardo@habkost.net, berrange@redhat.com, pbonzini@redhat.com, hreitz@redhat.com, kwolf@redhat.com, yc-core@yandex-team.ru Subject: Re: [PATCH v4 3/3] qapi: introduce device-sync-config In-Reply-To: <20240429101623.1992943-4-vsementsov@yandex-team.ru> (Vladimir Sementsov-Ogievskiy's message of "Mon, 29 Apr 2024 13:16:23 +0300") References: <20240429101623.1992943-1-vsementsov@yandex-team.ru> <20240429101623.1992943-4-vsementsov@yandex-team.ru> Date: Tue, 30 Apr 2024 10:19:33 +0200 Message-ID: <877cgfcley.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.987, 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=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: 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 Vladimir Sementsov-Ogievskiy writes: > Add command to sync config from vhost-user backend to the device. It > may be helpful when VHOST_USER_SLAVE_CONFIG_CHANGE_MSG failed or not > triggered interrupt to the guest or just not available (not supported > by vhost-user server). > > Command result is racy if allow it during migration. Let's allow the > sync only in RUNNING state. > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > hw/block/vhost-user-blk.c | 1 + > hw/virtio/virtio-pci.c | 9 ++++++++ > include/hw/qdev-core.h | 3 +++ > qapi/qdev.json | 23 +++++++++++++++++++ > system/qdev-monitor.c | 48 +++++++++++++++++++++++++++++++++++++++ > 5 files changed, 84 insertions(+) > > diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c > index 091d2c6acf..2f301f380c 100644 > --- a/hw/block/vhost-user-blk.c > +++ b/hw/block/vhost-user-blk.c > @@ -588,6 +588,7 @@ static void vhost_user_blk_class_init(ObjectClass *klass, void *data) > > device_class_set_props(dc, vhost_user_blk_properties); > dc->vmsd = &vmstate_vhost_user_blk; > + dc->sync_config = vhost_user_blk_sync_config; > set_bit(DEVICE_CATEGORY_STORAGE, dc->categories); > vdc->realize = vhost_user_blk_device_realize; > vdc->unrealize = vhost_user_blk_device_unrealize; > diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c > index b1d02f4b3d..0d91e8b5dc 100644 > --- a/hw/virtio/virtio-pci.c > +++ b/hw/virtio/virtio-pci.c > @@ -2351,6 +2351,14 @@ static void virtio_pci_dc_realize(DeviceState *qdev, Error **errp) > vpciklass->parent_dc_realize(qdev, errp); > } > > +static int virtio_pci_sync_config(DeviceState *dev, Error **errp) > +{ > + VirtIOPCIProxy *proxy = VIRTIO_PCI(dev); > + VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus); > + > + return qdev_sync_config(DEVICE(vdev), errp); > +} > + > static void virtio_pci_class_init(ObjectClass *klass, void *data) > { > DeviceClass *dc = DEVICE_CLASS(klass); > @@ -2367,6 +2375,7 @@ static void virtio_pci_class_init(ObjectClass *klass, void *data) > device_class_set_parent_realize(dc, virtio_pci_dc_realize, > &vpciklass->parent_dc_realize); > rc->phases.hold = virtio_pci_bus_reset_hold; > + dc->sync_config = virtio_pci_sync_config; > } > > static const TypeInfo virtio_pci_info = { > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h > index 9228e96c87..87135bdcdf 100644 > --- a/include/hw/qdev-core.h > +++ b/include/hw/qdev-core.h > @@ -95,6 +95,7 @@ typedef void (*DeviceUnrealize)(DeviceState *dev); > typedef void (*DeviceReset)(DeviceState *dev); > typedef void (*BusRealize)(BusState *bus, Error **errp); > typedef void (*BusUnrealize)(BusState *bus); > +typedef int (*DeviceSyncConfig)(DeviceState *dev, Error **errp); > > /** > * struct DeviceClass - The base class for all devices. > @@ -162,6 +163,7 @@ struct DeviceClass { > DeviceReset reset; > DeviceRealize realize; > DeviceUnrealize unrealize; > + DeviceSyncConfig sync_config; > > /** > * @vmsd: device state serialisation description for > @@ -546,6 +548,7 @@ bool qdev_hotplug_allowed(DeviceState *dev, Error **errp); > */ > HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev); > void qdev_unplug(DeviceState *dev, Error **errp); > +int qdev_sync_config(DeviceState *dev, Error **errp); > void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev, > DeviceState *dev, Error **errp); > void qdev_machine_creation_done(void); > diff --git a/qapi/qdev.json b/qapi/qdev.json > index facaa0bc6a..fc5e125a45 100644 > --- a/qapi/qdev.json > +++ b/qapi/qdev.json > @@ -161,3 +161,26 @@ > ## > { 'event': 'DEVICE_UNPLUG_GUEST_ERROR', > 'data': { '*device': 'str', 'path': 'str' } } > + > +## > +# @device-sync-config: > +# > +# Synchronize device configuration from host to guest part. First, > +# copy the configuration from the host part (backend) to the guest > +# part (frontend). Then notify guest software that device > +# configuration changed. Blank line here, please. > +# The command may be used to notify the guest about block device > +# capcity change. Currently only vhost-user-blk device supports > +# this. > +# > +# @id: the device's ID or QOM path > +# > +# Features: > +# > +# @unstable: The command is experimental. > +# > +# Since: 9.1 > +## > +{ 'command': 'device-sync-config', > + 'features': [ 'unstable' ], > + 'data': {'id': 'str'} } > diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c > index 264978aa40..47bfc0506e 100644 > --- a/system/qdev-monitor.c > +++ b/system/qdev-monitor.c > @@ -23,6 +23,7 @@ > #include "monitor/monitor.h" > #include "monitor/qdev.h" > #include "sysemu/arch_init.h" > +#include "sysemu/runstate.h" > #include "qapi/error.h" > #include "qapi/qapi-commands-qdev.h" > #include "qapi/qmp/dispatch.h" > @@ -971,6 +972,53 @@ void qmp_device_del(const char *id, Error **errp) > } > } > > +int qdev_sync_config(DeviceState *dev, Error **errp) > +{ > + DeviceClass *dc = DEVICE_GET_CLASS(dev); > + > + if (!dc->sync_config) { > + error_setg(errp, "device-sync-config is not supported for '%s'", > + object_get_typename(OBJECT(dev))); > + return -ENOTSUP; > + } > + > + return dc->sync_config(dev, errp); > +} > + > +void qmp_device_sync_config(const char *id, Error **errp) > +{ > + DeviceState *dev; > + > + /* > + * During migration there is a race between syncing`configuration and > + * migrating it (if migrate first, that target would get outdated version), > + * so let's just not allow it. Wrap comment lines around column 70 for legibility, please. > + * > + * Moreover, let's not rely on setting up interrupts in paused > + * state, which may be a part of migration process. We discussed this in review of v3. You wanted to check whether the problem is real. Is it? > + */ > + > + if (migration_is_running()) { > + error_setg(errp, "Config synchronization is not allowed " > + "during migration"); > + return; > + } > + > + if (!runstate_is_running()) { > + error_setg(errp, "Config synchronization allowed only in '%s' state, " Suggest a line break after errp, > + "current state is '%s'", RunState_str(RUN_STATE_RUNNING), > + RunState_str(runstate_get())); > + return; > + } > + > + dev = find_device_state(id, true, errp); > + if (!dev) { > + return; > + } > + > + qdev_sync_config(dev, errp); > +} > + > void hmp_device_add(Monitor *mon, const QDict *qdict) > { > Error *err = NULL;