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 lists1p.gnu.org (lists1p.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 CB668C43458 for ; Mon, 13 Jul 2026 09:51:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wjDJx-0002zO-Us; Mon, 13 Jul 2026 05:51:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wjDJs-0002z6-Q5 for qemu-devel@nongnu.org; Mon, 13 Jul 2026 05:51:24 -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 1wjDJr-00046v-2N for qemu-devel@nongnu.org; Mon, 13 Jul 2026 05:51:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783936282; h=from:from:reply-to: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=5wlxbAq4pDK3cgqDS5mWb3MH/RxUPgffkK4ECP7xfbs=; b=gn+waNb6689zo2b3Yofo3KpTZw8z/wwE9WWWAZll+tpmQfb4vWRYxzQd1wpx/ZTxecsWKO xI0TWmspJwdy6iigVEYjoyrNFyH1Qga8Qy4CS0Sp4CAIZ08erkzmVdzuu7AGkI8r3ge15I uUNFwWV/rzoRjS8fPNS1IKbCAyn9Sfk= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-9-EyJLA95PMkGj9kVElF7zhw-1; Mon, 13 Jul 2026 05:51:18 -0400 X-MC-Unique: EyJLA95PMkGj9kVElF7zhw-1 X-Mimecast-MFC-AGG-ID: EyJLA95PMkGj9kVElF7zhw_1783936277 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AFE1B180064A; Mon, 13 Jul 2026 09:51:16 +0000 (UTC) Received: from redhat.com (unknown [10.44.50.22]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0B9B6180065F; Mon, 13 Jul 2026 09:51:11 +0000 (UTC) Date: Mon, 13 Jul 2026 10:51:08 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Vladimir Sementsov-Ogievskiy Cc: jasowang@redhat.com, mst@redhat.com, armbru@redhat.com, peterx@redhat.com, farosas@suse.de, raphael.s.norwitz@gmail.com, bchaney@akamai.com, qemu-devel@nongnu.org, pbonzini@redhat.com, yc-core@yandex-team.ru, mark.caveayland@nutanix.com, Eric Blake Subject: Re: [PATCH v18 09/14] qapi: add local migration parameter Message-ID: References: <20260710191809.721154-1-vsementsov@yandex-team.ru> <20260710191809.721154-10-vsementsov@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260710191809.721154-10-vsementsov@yandex-team.ru> User-Agent: Mutt/2.3.2 (2026-04-26) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: permerror client-ip=170.10.129.124; envelope-from=berrange@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_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_PASS=-0.001, T_SPF_PERMERROR=0.01 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Jul 10, 2026 at 10:17:58PM +0300, Vladimir Sementsov-Ogievskiy wrote: > 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 devices that support it (none at the moment). > > Signed-off-by: Vladimir Sementsov-Ogievskiy > Acked-by: Markus Armbruster > Acked-by: Peter Xu > Reviewed-by: Ben Chaney > --- > include/migration/misc.h | 2 ++ > migration/options.c | 18 +++++++++++++++++- > qapi/migration.json | 12 ++++++++++-- > 3 files changed, 29 insertions(+), 3 deletions(-) > diff --git a/qapi/migration.json b/qapi/migration.json > index 66bd900465a..03bdf19f3a6 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -830,7 +830,8 @@ > 'zero-page-detection', > 'direct-io', > { 'name': 'x-rdma-chunk-size', 'features': [ 'unstable' ] }, > - 'cpr-exec-command'] } > + 'cpr-exec-command', > + 'local'] } > > ## > # @migrate-set-parameters: > @@ -1012,6 +1013,12 @@ > # Must be set to the same value on both source and destination > # before migration starts. (Since 11.1) > # > +# @local: Enable local migration for devices that support it. Backend > +# state and its file descriptors can then be passed to the > +# destination in the migration channel. The migration channel > +# must be a Unix domain socket. Usually needs to be enabled per > +# device. (Since 11.2) What happens when this is enabled and there are devices which don't support it ? What happens when this is enabled and a device on the src does not support it but a device on the (newer) QEMU dest does support it ? How does the mgmt app know which devices support it ? Can we document the semantics in these cases. > +# > # Features: > # > # @unstable: Members @x-checkpoint-delay, @x-rdma-chunk-size, and > @@ -1053,7 +1060,8 @@ > '*direct-io': 'bool', > '*x-rdma-chunk-size': { 'type': 'uint64', > 'features': [ 'unstable' ] }, > - '*cpr-exec-command': [ 'str' ]} } > + '*cpr-exec-command': [ 'str' ], > + '*local': 'bool' } } > > ## > # @query-migrate-parameters: > -- > 2.43.0 > With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|