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 1EE23E9539C for ; Wed, 4 Feb 2026 13:08:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vnccL-0003bH-56; Wed, 04 Feb 2026 08:08:25 -0500 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 1vnccJ-0003b7-VL for qemu-devel@nongnu.org; Wed, 04 Feb 2026 08:08:23 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vnccI-0007QZ-7Z for qemu-devel@nongnu.org; Wed, 04 Feb 2026 08:08:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770210501; 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=8+48y17rmgCRAVb1aKA4ukwPDg7phhqainuUs5j16l0=; b=FzByfV9v+4qfpEYPSGZXyqWUpOuTCc0aW2F8ZYOiqSWFQCkeTPTbAoU4SiKp8kYexrW9Hy W5WN9acPrR5tDF8SaKINxLOOekWHOkZMn/sZPD7GoDz77NoT/VqAxuwUg9sFli3l3LFT2D uORXVgOeDtRZf6N0rEyvANObnw+6fDs= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-124-Ixwc3Ka9NQ6L0eMRHUjvQw-1; Wed, 04 Feb 2026 08:08:18 -0500 X-MC-Unique: Ixwc3Ka9NQ6L0eMRHUjvQw-1 X-Mimecast-MFC-AGG-ID: Ixwc3Ka9NQ6L0eMRHUjvQw_1770210496 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 88B4619560AE; Wed, 4 Feb 2026 13:08:15 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.22]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 369F21800464; Wed, 4 Feb 2026 13:08:14 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id D38F721E692D; Wed, 04 Feb 2026 14:08:11 +0100 (CET) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Cc: jasowang@redhat.com, mst@redhat.com, pbonzini@redhat.com, berrange@redhat.com, thuth@redhat.com, eblake@redhat.com, farosas@suse.de, peterx@redhat.com, zhao1.liu@intel.com, wangyanan55@huawei.com, philmd@linaro.org, marcel.apfelbaum@gmail.com, eduardo@habkost.net, davydov-max@yandex-team.ru, qemu-devel@nongnu.org, yc-core@yandex-team.ru, leiyang@redhat.com, raphael.s.norwitz@gmail.com, bchaney@akamai.com Subject: Re: [PATCH v10 3/8] qapi: add backend-transfer migration parameter In-Reply-To: <20260201162001.296328-4-vsementsov@yandex-team.ru> (Vladimir Sementsov-Ogievskiy's message of "Sun, 1 Feb 2026 19:19:55 +0300") References: <20260201162001.296328-1-vsementsov@yandex-team.ru> <20260201162001.296328-4-vsementsov@yandex-team.ru> Date: Wed, 04 Feb 2026 14:08:11 +0100 Message-ID: <87tsvwwtac.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 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: 2.1.29 Precedence: list List-Id: qemu development 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: > We are going to implement backend-transfer feature: some devices > will be able to transfer their backend through migration stream > for local migration through UNIX domain socket. For example, > virtio-net will migrate its attached TAP netdev, with all its > connected file descriptors. > > In this commit we introduce a migration parameter, which enables > the feature, for supporting devices (no one at the moment). > > Signed-off-by: Vladimir Sementsov-Ogievskiy [...] > void qmp_migrate_set_parameters(MigrationParameters *params, Error **errp) > diff --git a/qapi/migration.json b/qapi/migration.json > index f925e5541b..cbe88f0c91 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -828,7 +828,8 @@ > 'mode', > 'zero-page-detection', > 'direct-io', > - 'cpr-exec-command'] } > + 'cpr-exec-command', > + 'backend-transfer'] } > > ## > # @migrate-set-parameters: > @@ -1004,6 +1005,13 @@ > # is @cpr-exec. The first list element is the program's filename, > # the remainder its arguments. (Since 10.2) > # > +# @backend-transfer: Enable backend-transfer feature for devices that > +# supports it. In general that means that backend state and its support > +# file descriptors are passed to the destination in the migraton > +# channel (which must be a UNIX socket). Individual devices > +# declare the support for backend-transfer by per-device > +# backend-transfer option. (Since 11.0) > +# > # Features: > # > # @unstable: Members @x-checkpoint-delay and > @@ -1043,7 +1051,8 @@ > '*mode': 'MigMode', > '*zero-page-detection': 'ZeroPageDetection', > '*direct-io': 'bool', > - '*cpr-exec-command': [ 'str' ]} } > + '*cpr-exec-command': [ 'str' ], > + '*backend-transfer': 'bool' } } > > ## > # @query-migrate-parameters: With the grammar fix, QAPI schema Acked-by: Markus Armbruster