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 7939BFD2D99 for ; Tue, 10 Mar 2026 13:54:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vzxWi-00037S-HR; Tue, 10 Mar 2026 09:53:36 -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 1vzxWf-00036x-IG for qemu-devel@nongnu.org; Tue, 10 Mar 2026 09:53:33 -0400 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 1vzxWd-0005zP-Ae for qemu-devel@nongnu.org; Tue, 10 Mar 2026 09:53:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1773150808; 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=QwPGxLKyl4WnkrlRO4iCkB05zSTeBuf2ShTthp2skEo=; b=QnSeLGzjFd9w/yeD//a8qlH4gBOIDATIqoR8q7BWbKnfbRfds8RP7AdN4qHed01fWLlsei bBqyE2sS+FDtN9E3wVL6U9IvGM4Q3CY6w5T5t9zSiYXJ6NcQ00ZX1P+S1FpqP7s8D5gtOP tguwSs6AFbYrAZGvUUKgjz0MWhMc5Hk= Received: from mx-prod-mc-01.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-592-Pdakyj_5OXWOjGEh5tk7tA-1; Tue, 10 Mar 2026 09:53:23 -0400 X-MC-Unique: Pdakyj_5OXWOjGEh5tk7tA-1 X-Mimecast-MFC-AGG-ID: Pdakyj_5OXWOjGEh5tk7tA_1773150801 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 87D221956094; Tue, 10 Mar 2026 13:53:20 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.12]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 915711956095; Tue, 10 Mar 2026 13:53:19 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3DA9F21E6614; Tue, 10 Mar 2026 14:53:17 +0100 (CET) From: Markus Armbruster To: Vladimir Sementsov-Ogievskiy Cc: jasowang@redhat.com, mst@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 v12 3/8] qapi: add local migration parameter In-Reply-To: <20260306213235.216863-4-vsementsov@yandex-team.ru> (Vladimir Sementsov-Ogievskiy's message of "Sat, 7 Mar 2026 00:32:30 +0300") References: <20260306213235.216863-1-vsementsov@yandex-team.ru> <20260306213235.216863-4-vsementsov@yandex-team.ru> Date: Tue, 10 Mar 2026 14:53:17 +0100 Message-ID: <87cy1biyeq.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 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: -3 X-Spam_score: -0.4 X-Spam_bar: / X-Spam_report: (-0.4 / 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.819, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.903, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no 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 local-migration feature: some devices will be > able to transfer open file descriptors through migration stream (which > must UNIX domain socket for that purpose). This allows to transfer the > whole backend state without reconnecting and restarting the backend > service. For example, virtio-net will migrate its attached TAP netdev, > together with its connected file descriptors. > > In this commit we introduce a migration parameter, which enables > the feature for supporting devices (no one at the moment). for devices that support it (none at the moment). > > Signed-off-by: Vladimir Sementsov-Ogievskiy > Reviewed-by: Peter Xu [...] > diff --git a/qapi/migration.json b/qapi/migration.json > index f925e5541bf..2c8d85f5834 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', > + 'local'] } > > ## > # @migrate-set-parameters: > @@ -1004,6 +1005,15 @@ > # is @cpr-exec. The first list element is the program's filename, > # the remainder its arguments. (Since 10.2) > # > +# @local: Enable local migration feature for devices that support > +# it. The feature is for local migration only and rely on the > +# channel support for passing file descriptors (it must be a UNIX > +# socket). In general that means that backend state and its file > +# descriptors are passed to the destination in the migration > +# channel. In general devices may have an option which in > +# conjunction with @local set to true enables the local-migration > +# feature for that device. (Since 11.0) This needs polish. Let me try. # @local: Enable local migration for devices that support it. Backend # state and its file descriptors are then passed to the # destination in the migration channel. The migration channel # must be a Unix domain socket. Also needs to be enabled per # device by setting device property "local" to true. > +# > # Features: > # > # @unstable: Members @x-checkpoint-delay and > @@ -1043,7 +1053,8 @@ > '*mode': 'MigMode', > '*zero-page-detection': 'ZeroPageDetection', > '*direct-io': 'bool', > - '*cpr-exec-command': [ 'str' ]} } > + '*cpr-exec-command': [ 'str' ], > + '*local': 'bool' } } > > ## > # @query-migrate-parameters: