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 ACF3EC87FD3 for ; Fri, 8 Aug 2025 10:48:56 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ukKeC-0002gf-Tm; Fri, 08 Aug 2025 06:48:28 -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 1ukKeA-0002ck-GO for qemu-devel@nongnu.org; Fri, 08 Aug 2025 06:48:26 -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 1ukKe8-0004Qd-Fe for qemu-devel@nongnu.org; Fri, 08 Aug 2025 06:48:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754650102; 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=rRkzzxR1VVIbbYj6enXKWSSXJfM5rw+2FQewa+7Zugk=; b=iCIndarCdnRoRNQipeUyluVyaOyxBKkvaQ6SPDz34botgfxsUAblBxtyBwZILmjiQA3tpL yhrrvgWjrRrx73aNYHGqxh3CQVXTaJbdobihZbneZv/8abkbP/wuqqQJAAnYsSo0erbPC1 gFBofkXPgg6wKX0qTxhs26WDbQ5qsuA= 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-683-YreWYYbANV6ZwYElSvfxcw-1; Fri, 08 Aug 2025 06:48:19 -0400 X-MC-Unique: YreWYYbANV6ZwYElSvfxcw-1 X-Mimecast-MFC-AGG-ID: YreWYYbANV6ZwYElSvfxcw_1754650098 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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 2C6991955E7F; Fri, 8 Aug 2025 10:48:18 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.18]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B51C63001455; Fri, 8 Aug 2025 10:48:17 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3633E21E6A27; Fri, 08 Aug 2025 12:48:14 +0200 (CEST) From: Markus Armbruster To: Jonah Palmer Cc: qemu-devel@nongnu.org, peterx@redhat.com, farosas@suse.de, eblake@redhat.com, armbru@redhat.com, jasowang@redhat.com, mst@redhat.com, si-wei.liu@oracle.com, eperezma@redhat.com, boris.ostrovsky@oracle.com Subject: Re: [RFC 1/6] migration: Add virtio-iterative capability In-Reply-To: <20250722124127.2497406-2-jonah.palmer@oracle.com> (Jonah Palmer's message of "Tue, 22 Jul 2025 12:41:22 +0000") References: <20250722124127.2497406-1-jonah.palmer@oracle.com> <20250722124127.2497406-2-jonah.palmer@oracle.com> Date: Fri, 08 Aug 2025 12:48:14 +0200 Message-ID: <874iuihyxd.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 10.30.177.4 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: -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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_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: 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 I apologize for the lateness of my review. Jonah Palmer writes: > Adds a new migration capability 'virtio-iterative' that will allow > virtio devices, where supported, to iteratively migrate configuration > changes that occur during the migration process. Why is that desirable? > This capability is added to the validated capabilities list to ensure > both the source and destination support it before enabling. What happens when only one side enables it? > The capability defaults to off to maintain backward compatibility. > > To enable the capability via HMP: > (qemu) migrate_set_capability virtio-iterative on > > To enable the capability via QMP: > {"execute": "migrate-set-capabilities", "arguments": { > "capabilities": [ > { "capability": "virtio-iterative", "state": true } > ] > } > } > > Signed-off-by: Jonah Palmer > --- > migration/savevm.c | 1 + > qapi/migration.json | 7 ++++++- > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/migration/savevm.c b/migration/savevm.c > index bb04a4520d..40a2189866 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -279,6 +279,7 @@ static bool should_validate_capability(int capability) > switch (capability) { > case MIGRATION_CAPABILITY_X_IGNORE_SHARED: > case MIGRATION_CAPABILITY_MAPPED_RAM: > + case MIGRATION_CAPABILITY_VIRTIO_ITERATIVE: > return true; > default: > return false; > diff --git a/qapi/migration.json b/qapi/migration.json > index 4963f6ca12..8f042c3ba5 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -479,6 +479,11 @@ > # each RAM page. Requires a migration URI that supports seeking, > # such as a file. (since 9.0) > # > +# @virtio-iterative: Enable iterative migration for virtio devices, if > +# the device supports it. When enabled, and where supported, virtio > +# devices will track and migrate configuration changes that may > +# occur during the migration process. (Since 10.1) When and why should the user enable this? What exactly do you mean by "where supported"? docs/devel/qapi-code-gen.rst: For legibility, wrap text paragraphs so every line is at most 70 characters long. Separate sentences with two spaces. > +# > # Features: > # > # @unstable: Members @x-colo and @x-ignore-shared are experimental. > @@ -498,7 +503,7 @@ > { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, > 'validate-uuid', 'background-snapshot', > 'zero-copy-send', 'postcopy-preempt', 'switchover-ack', > - 'dirty-limit', 'mapped-ram'] } > + 'dirty-limit', 'mapped-ram', 'virtio-iterative'] } > > ## > # @MigrationCapabilityStatus: