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 1FC4AFF493A for ; Mon, 30 Mar 2026 05:12:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1w74ud-00027Q-KO; Mon, 30 Mar 2026 01:11:45 -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 1w74uL-00026p-Nm for qemu-devel@nongnu.org; Mon, 30 Mar 2026 01:11:27 -0400 Received: from mgamail.intel.com ([192.198.163.18]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1w74uJ-0002tK-VZ for qemu-devel@nongnu.org; Mon, 30 Mar 2026 01:11:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1774847484; x=1806383484; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=dmwMMcDYcAa6hBKkGozfmUQZoylD24wVipEXWxaZ6ok=; b=e7pp2UT1Umkv4n9hqQnQoYt8HAOHvKfOtUfoF3BdrzCQ/m5HCKoJUBm/ Pze2vrLjE9hoo003KUR8IrXeBp4tZfoCyik8ou3CPhKYPFxSgCKyPgI+G Jq6ykWuMa8zwr8DKmoMoeGkOnLPrwxEQSFxwX9IZJSS1NCA58J6f0KDre eWY+3E9xwSl+DXLez2BkXtcK0CD5F7VxUoLZbnIZgUo8NiaoW+v7U+h1p sfiBnNIjdSIuNcMFp/zPNsjDip7W1sPRo0+xPc8Kwoarj9aGSO4qHrF8n Y2HUhg/sOIt7QZMGWxF9Ri0a2EAWflQj9i1tw7ju6x//2nD9G8ipll/re g==; X-CSE-ConnectionGUID: 5REGrfiNTWOUQzRnqYNOhw== X-CSE-MsgGUID: Fwmu/T6nSdmbqRw1lTqriQ== X-IronPort-AV: E=McAfee;i="6800,10657,11743"; a="75009526" X-IronPort-AV: E=Sophos;i="6.23,149,1770624000"; d="scan'208";a="75009526" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Mar 2026 22:11:22 -0700 X-CSE-ConnectionGUID: eJcbkJTGTS2F1zgeKBAwig== X-CSE-MsgGUID: b377fU6ZRwW88yRSm8ZC/Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,149,1770624000"; d="scan'208";a="227563613" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.39]) by fmviesa004.fm.intel.com with ESMTP; 29 Mar 2026 22:11:20 -0700 Date: Mon, 30 Mar 2026 13:37:38 +0800 From: Zhao Liu To: Peter Maydell Cc: Igor Mammedov , Paolo Bonzini , qemu-devel@nongnu.org, Fabiano Rosas , Peter Xu , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Aurelien Jarno , Zhao Liu Subject: Re: [PULL 04/41] pc: Start with modern CPU hotplug interface by default Message-ID: References: <20260212144244.22579-1-pbonzini@redhat.com> <20260212144244.22579-5-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=192.198.163.18; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=1, RCVD_IN_VALIDITY_RPBL_BLOCKED=1, 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: 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 On Sun, Mar 29, 2026 at 01:35:15PM +0100, Peter Maydell wrote: > Date: Sun, 29 Mar 2026 13:35:15 +0100 > From: Peter Maydell > Subject: Re: [PULL 04/41] pc: Start with modern CPU hotplug interface by > default > > On Tue, 17 Mar 2026 at 03:57, Zhao Liu wrote: > > > > +Philippe & Aurelien > > > > (And seeking Igor's input) > > > > > The problem is that the vmstate_cpu_hotplug VMStateDescription > > > that is being used has a NULL "fields" (it is the "stub" one). > > > This used to be OK because the "piix4_pm/cpuhp" vmstate had > > > a "needed" function that would return false for Malta, so we > > > never tried to use the stub code. > > > > > > What's the intention here ? Shouldn't we still have a "needed" > > > function that returns "false" for the cases where we would be > > > using the stub version of vmstate_cpu_hotplug ? Otherwise we > > > would be changing the migration data. We can permit a compat > > > break for MIPS boards, but the commit message suggests that > > > this wasn't intended to be a compat break. > > > > Thanks, this is my bad - I didn't realize it would break Malta. The > > "needed" method looks necessary, but previously making the "stub" one > > depend on cpu_hotplug_legacy=true also sounds a bit not proper. > > > > Maybe in the needed() method we should also check whether the board/ > > machine supports CPU hotplug: check mc->has_hotpluggable_cpus. IIUC, > > Malta doesn't support this. > > > > > In this thread Fabiano suggests a fix which is probably OK > > > if we want to take the "break migration compat" route: > > > https://lore.kernel.org/qemu-devel/CAFEAcA9BzSp9F8yv4eZv5eeUM4JXSy9T-QnRr_UbJZpNmhtHyw@mail.gmail.com/T/#m6f4a672ddfa8a0a34dfdf9b57bb04e529ab5c9a4 > > > > I think Fabiano's patch is a clean solution. Or I think there's another > > option: we can bring needed() back but check mc->has_hotpluggable_cpus > > instead, like acpi-ged/cpuhp did (). > > > > Igor, what do you think? > > Hi, what's the plan here ? We need to fix this before 11.0 > releases. Are you going to send your proposed ich9.c fix > as a proper patch ? Hi Peter, Now I post a patch here: https://lore.kernel.org/qemu-devel/20260330053008.2721532-1-zhao1.liu@intel.com Thanks, Zhao