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 B7447CD6E55 for ; Wed, 3 Jun 2026 17:17:00 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wUpCV-00005W-1n; Wed, 03 Jun 2026 13:16:19 -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 1wUpCR-0008W4-MA for qemu-devel@nongnu.org; Wed, 03 Jun 2026 13:16:17 -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 1wUpCP-0006Bm-4h for qemu-devel@nongnu.org; Wed, 03 Jun 2026 13:16:15 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780506971; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=n+bq0CaMYt7tHmdYI9bIrzKoRjv74q4Q1koF9CvivuU=; b=FwEc6bIdV7Qg49WVipN8wY5USr7ykIS+8/FUioDzUbZWqTgVslhwqQRSX9f8zMGd4fqo+O Cb3jXAI9bHtVyFJBIfM3L5EPXUg4bVInghdUPZo4hQ8r5C7KWYjMFVC0JN5WgazBj7agXU ccPHadcHOogZ9DS8NgTu6dJrsbPpLk0= 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-679-jc_0t80CMb2XowCdWLp6KQ-1; Wed, 03 Jun 2026 13:16:07 -0400 X-MC-Unique: jc_0t80CMb2XowCdWLp6KQ-1 X-Mimecast-MFC-AGG-ID: jc_0t80CMb2XowCdWLp6KQ_1780506966 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 074771800345; Wed, 3 Jun 2026 17:16:06 +0000 (UTC) Received: from redhat.com (unknown [10.44.50.34]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9087E30001A1; Wed, 3 Jun 2026 17:16:01 +0000 (UTC) Date: Wed, 3 Jun 2026 18:15:57 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Xu Cc: Fabiano Rosas , qemu-devel@nongnu.org, Paolo Bonzini , Mark Kanda , "Michael S . Tsirkin" , Markus Armbruster , Eric Blake , "Maciej S. Szmigiero" , Jason Wang , Ben Chaney , Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH RFC 0/2] migration/vl: new -incoming config:* for early migration parameters Message-ID: References: <20260528212947.368132-1-peterx@redhat.com> <87se7btcq9.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.3.1 (2026-03-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, 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=0.001, RCVD_IN_MSPIKE_WL=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: , 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 Wed, Jun 03, 2026 at 11:50:53AM -0400, Peter Xu wrote: > On Wed, Jun 03, 2026 at 10:48:54AM +0100, Daniel P. Berrangé wrote: > > On Fri, May 29, 2026 at 10:15:35AM -0400, Peter Xu wrote: > > > On Thu, May 28, 2026 at 07:01:50PM -0300, Fabiano Rosas wrote: > > > > Peter Xu writes: > > > > > > > > > CI: https://gitlab.com/peterx/qemu/-/pipelines/2560168907 > > > > > > > > > > This series introduces a generic way to specify migration parameters that > > > > > can be used even during the early boot phase of QEMU. > > > > > > > > > > One example use case that already existed is CPR-transfer / CPR-exec. > > > > > currently QEMU has a temporary global variable (incoming_mode) to achieve > > > > > this, but it's hard to understand and this hack bleeded into quite a few > > > > > places that we could have avoided. The lines in patch 2 touched may > > > > > provide some idea. > > > > > > > > > > With a generic approach of setting migration parameters with cmdlines, we > > > > > can remove this hack meanwhile QEMU should be able to keep the CPR behavior > > > > > as before. To CPR maintainers and reviewers: please have a closer look, > > > > > even better if it can be smoke tested, to see if this works for Oracle's > > > > > environment, TIA. > > > > > > > > > > The 1st patch implemented that new semantics. It is straightforward: now > > > > > we can setup any migration parameter using an extra line of: > > > > > > > > > > -incoming config:key1=value1,key2=value2,... snip > > > > - using "config:" > > > > > > > > This makes it non-uniform with uri and channels which don't have a > > > > keyword in front of them. I guess I could live with it, but it seems > > > > odd. I see that it makes parsing way easier. > > > > > > Yeah, having some identifier would be nice. I wished channels also have > > > identifiers if we don't need to keep compatibility. > > > > IMHO having a magic "config:" prefix is an anti-pattern because it > > involves custom command line parsing logic. > > Yes, it's not elegant. I wished we had something like this though when > introducing the cpr channels; right now anything wasn't "defer" or URI > implies it's a "channel".. > > I also wanted to avoid introducing new cmdline parameters, so migration > incoming cmdlines can stick with the same option. If there's better > suggestion please shoot. > > > > > Does "-incoming config" imply '-incoming defer' semantics or is it > > independent ? > > They're independent. Examples: > > a) "-incoming config:* -incoming tcp:*", setup parameters for TCP incoming > migration without further deferral > > b) "-incoming config:*" only, setup global parameters for a possible > upcoming outgoing migration In that case they should definitely be independent command line options. The old "-incoming" design is already broken / limited in the non-'defer' case because it is hardcoded to use URI syntax which can't express all the address formats we accept in QAPI syntax. Adding more special cases onto -incoming just makes the bad situation even worse and is not a forward looking design. If we need the ability to specify migration parameters on the CLI, then as a starting point for the design, we should assume that -incoming does not exist, and design a complete solution from scratch that uses QAPI exclusively, both for addresses and configuration. As discussed before, IMHO the "migrate" and "migrate-incoming" commands need to accept both the address(s) and parameters/capabilities as inline data items rather than relying on pre-configured global state from the 'migrate-parameter' / 'migrate-capability' commands. If we did that modelling for 'migrate-incoming' then that modelling of command parmaeters could map directly to a new '-migrate-incoming' command line argument that accepted exactly the same data model. 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 :|