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 CBD4DC05027 for ; Wed, 8 Feb 2023 20:18:00 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pPqsf-0000Pi-9K; Wed, 08 Feb 2023 15:17:25 -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 1pPqsa-0000Mh-Ma for qemu-devel@nongnu.org; Wed, 08 Feb 2023 15:17:21 -0500 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 1pPqsY-0001OF-Hz for qemu-devel@nongnu.org; Wed, 08 Feb 2023 15:17:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1675887437; 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=SzJ2jg7gOAPuK7eojaO3K+xFnEbZfpLaBArnmcXk2y8=; b=AZPf8XFelCijwZHpUStiCRUtVBhwVTndud/cHUO0Xi67/ylftll0Q7VpVQZQUazBJmM8er uGjF4D4jM0/5d/3wPynyG00u6Z9pyS8d98bPXaRbqwwFwa3rJat6iZrbYaMPtkeNrAKh8I /HOevM5Ffbf2LntnI50C6zvB5TAvWWg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-439-qIy3piJTPmGhLl6IsSS1UA-1; Wed, 08 Feb 2023 15:17:15 -0500 X-MC-Unique: qIy3piJTPmGhLl6IsSS1UA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 455F8811E6E; Wed, 8 Feb 2023 20:17:15 +0000 (UTC) Received: from redhat.com (unknown [10.2.16.104]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5CC3140B3FE1; Wed, 8 Feb 2023 20:17:14 +0000 (UTC) Date: Wed, 8 Feb 2023 14:17:12 -0600 From: Eric Blake To: Het Gala Cc: qemu-devel@nongnu.org, prerna.saxena@nutanix.com, quintela@redhat.com, dgilbert@redhat.com, pbonzini@redhat.com, berrange@redhat.com, armbru@redhat.com, manish.mishra@nutanix.com, aravind.retnakaran@nutanix.com Subject: Re: [PATCH v2 2/6] migration: Updated QAPI format for 'migrate' qemu monitor command Message-ID: <20230208201712.b3a5xtufscrvncqt@redhat.com> References: <20230208093600.242665-1-het.gala@nutanix.com> <20230208093600.242665-3-het.gala@nutanix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230208093600.242665-3-het.gala@nutanix.com> User-Agent: NeoMutt/20220429 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@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, SPF_HELO_NONE=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 On Wed, Feb 08, 2023 at 09:35:56AM +0000, Het Gala wrote: > Existing 'migrate' QAPI design enforces transport mechanism, ip address > of destination interface and corresponding port number in the form > of a unified string 'uri' parameter for initiating a migration stream. > This scheme has a significant flaw in it - double encoding of existing > URIs to extract migration info. > > The current patch maps QAPI uri design onto well defined MigrateChannel > struct. This modified QAPI helps in preventing multi-level uri > encodings ('uri' parameter is kept for backward compatibility). > > Suggested-by: Daniel P. Berrange > Suggested-by: Manish Mishra > Suggested-by: Aravind Retnakaran > Signed-off-by: Het Gala > --- > qapi/migration.json | 131 +++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 129 insertions(+), 2 deletions(-) > > diff --git a/qapi/migration.json b/qapi/migration.json > index c84fa10e86..79acfcfe4e 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -1449,12 +1449,108 @@ > ## > { 'command': 'migrate-continue', 'data': {'state': 'MigrationStatus'} } > > +## > +# @MigrateTransport: > +# > +# The supported communication transport mechanisms for migration > +# > +# @socket: Supported communication type between two devices for migration. > +# Socket is able to cover all of 'tcp', 'unix', 'vsock' and > +# 'fd' already > +# > +# @exec: Supported communication type to redirect migration stream into file. > +# > +# @rdma: Supported communication type to redirect rdma type migration stream. > +# > +# Since 8.0 > +## > +{ 'enum': 'MigrateTransport', > + 'data': ['socket', 'exec', 'rdma'] } > + > +## > +# @MigrateSocketAddr: > +# > +# To support different type of socket. > +# > +# @socket-type: Different type of socket connections. > +# > +# Since 8.0 > +## > +{ 'struct': 'MigrateSocketAddr', > + 'data': {'socket-type': 'SocketAddress' } } Here, you use 'socket-type',... > + > +## > +# @MigrateExecAddr: > + # > + # Since 8.0 > + ## > +{ 'struct': 'MigrateExecAddr', > + 'data' : {'data': ['str'] } } Inconsistent on whether you have a space before :. Most of our qapi files prefer the layout: 'key': 'value' that is, no space before, one space after. It doesn't affect correctness, but a consistent visual style is worth striving for. > + > +## > +# @MigrateRdmaAddr: > +# > +# Since 8.0 > +## > +{ 'struct': 'MigrateRdmaAddr', > + 'data' : {'data': 'InetSocketAddress' } } ...while these branches supply everything else under 'data'. Also, while you documented @socket-type above, you did not document @data in either of these two types. [1] > + > +## > +# @MigrateAddress: > +# > +# The options available for communication transport mechanisms for migration > +# > +# Since 8.0 > +## > +{ 'union' : 'MigrateAddress', > + 'base' : { 'transport' : 'MigrateTransport'}, > + 'discriminator' : 'transport', > + 'data' : { > + 'socket' : 'MigrateSocketAddr', > + 'exec' : 'MigrateExecAddr', > + 'rdma': 'MigrateRdmaAddr' } } Another example of inconsistent spacing around :. I'm guessing the reason you didn't go with 'socket': 'SocketAddress' is that SocketAddress is itself a discriminated union, and Markus does not yet have the QAPI generator wired up to support one union as a branch of another larger union? It leads to extra nesting on the wire [2] > + > +## > +# @MigrateChannelType: > +# > +# The supported options for migration channel type requests > +# > +# @main: Support request for main outbound migration control channel > +# > +# Since 8.0 > +## > +{ 'enum': 'MigrateChannelType', > + 'data': [ 'main'] } A different spacing issue: most arrays in QAPI either have spaces at both ends (as in [ 'string' ]) or neither (as in ['string']). Here, it looks lopsided with space at the front but not the back. > + > +## > +# @MigrateChannel: > +# > +# Information regarding migration Channel-type for transferring packets, > +# source and corresponding destination interface for socket connection > +# and number of multifd channels over the interface. > +# > +# @channeltype: Name of Channel type for transfering packet information > +# > +# @addr: SocketAddress of destination interface More than just a SocketAddress, per the discriminated union type defined above. > +# > +# Since 8.0 > +## > +{ 'struct': 'MigrateChannel', > + 'data' : { > + 'channeltype' : 'MigrateChannelType', > + 'addr' : 'MigrateAddress' } } > + > ## > # @migrate: > # > # Migrates the current running guest to another Virtual Machine. > # > # @uri: the Uniform Resource Identifier of the destination VM > +# for migration thread > +# > +# @channel: Struct containing migration channel type, along with all > +# the details of destination interface required for initiating > +# a migration stream. > # > # @blk: do block migration (full disk copy) > # > @@ -1479,15 +1575,46 @@ > # 3. The user Monitor's "detach" argument is invalid in QMP and should not > # be used > # > +# 4. The uri argument should have the Uniform Resource Identifier of default > +# destination VM. This connection will be bound to default network > +# > +# 5. Both 'uri' and 'channel' arguments, are mutually exclusive but, at least > +# one of the two arguments should be present. Grammar suggestion: 'uri' and 'channel' are mutually exclusive; exactly one of the two should be present. > +# > # Example: > # > # -> { "execute": "migrate", "arguments": { "uri": "tcp:0:4446" } } > # <- { "return": {} } > # > +# -> { "execute": "migrate", > +# "arguments": { > +# "channel": { "channeltype": "main", > +# "addr": { "transport": "socket", > +# "socket-type": { "type': "inet', > +# "host": "10.12.34.9", > +# "port": "1050" } } } } } [2] This is the extra nesting that occurs because of the 'socket-type':'MigrateSocketAddr' above; getting rid of the nesting would require 'socket-type':'SocketAddress', but QAPI would need to support that first. > +# <- { "return": {} } > +# > +# -> { "execute": "migrate", > +# "arguments": { > +# "channel": { "channeltype": "main", > +# "addr": { "transport": "exec", > +# "exec": ["/bin/nc", "-U", > +# "/some/sock" ] } } } } Another lopsided spacing in []. > +# <- { "return": {} } > +# > +# -> { "execute": "migrate", > +# "arguments": { > +# "channel": { "channeltype": "main", > +# "addr": { "transport": "rdma", > +# "rdma": { "host": "10.12.34.9", > +# "port": "1050" } } } } } [1] These examples look wrong; above, the schema named the nesting as 'data', rather than 'exec' or 'rdma'. > +# <- { "return": {} } > +# > ## > { 'command': 'migrate', > - 'data': {'uri': 'str', '*blk': 'bool', '*inc': 'bool', > - '*detach': 'bool', '*resume': 'bool' } } > + 'data': {'*uri': 'str', '*channel': 'MigrateChannel', '*blk': 'bool', > + '*inc': 'bool', '*detach': 'bool', '*resume': 'bool' } } > But overall, I'm a fan of using a more type-accurate description of the channel than the open-coded 'uri':'str'. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org