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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3542C4332F for ; Wed, 16 Nov 2022 13:29:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233720AbiKPN3q (ORCPT ); Wed, 16 Nov 2022 08:29:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233264AbiKPN3j (ORCPT ); Wed, 16 Nov 2022 08:29:39 -0500 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C97F4450A7 for ; Wed, 16 Nov 2022 05:29:35 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1668605375; x=1700141375; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=XUU7tDNgYGoWHHgbI4B+EDpkeBTZbCvGBKabd0d70uw=; b=OTNybwqBwSh72195APyCi4yYM5PwLwFqET6NQGjx7u0EpwAvgAscK4mL zfngwXuwWjmxeQTtRJTzgO5cT+iACnzALRiIclJGYuNmaf0pcv0E8yHgh edayo6XSr6n0mlpNp2Cexi1H5eLfEmWWjsJOw0IFw8+oZuGI5PVcSQihw VgHHKqPriPoltb9aP8WwovR6G3P0KS30+NCQjYVLghsacXC9uWdM8RTXw G5gzGYLjTVj79x9Z67atlpAE9HAXOSBM0QY8cH1ocvt8Dv3LxvZfMC0lP wd5b8w5wIC/zAXlGmHgRnQXfpY+2Uy4QpsAQfhreqDs77XzcfR68O0/cZ A==; X-IronPort-AV: E=McAfee;i="6500,9779,10532"; a="292248058" X-IronPort-AV: E=Sophos;i="5.96,167,1665471600"; d="scan'208";a="292248058" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Nov 2022 05:29:35 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10532"; a="672391618" X-IronPort-AV: E=Sophos;i="5.96,167,1665471600"; d="scan'208";a="672391618" Received: from smile.fi.intel.com ([10.237.72.54]) by orsmga001.jf.intel.com with ESMTP; 16 Nov 2022 05:29:33 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.96) (envelope-from ) id 1ovITs-00D8sV-0I; Wed, 16 Nov 2022 15:29:32 +0200 Date: Wed, 16 Nov 2022 15:29:31 +0200 From: Andy Shevchenko To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Fei Li , "Rafael J. Wysocki" Subject: Re: [PATCH v4 1/1] virt: acrn: Mark the uuid field as unused Message-ID: References: <20221116092254.66234-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 16, 2022 at 12:42:16PM +0100, Greg Kroah-Hartman wrote: > On Wed, Nov 16, 2022 at 11:22:54AM +0200, Andy Shevchenko wrote: > > After the commits for userspace (see Link tags below) the uuid field is > > not being used in the ACRN code. Update kernel to reflect these changes. > > I.e. we do the following: > > - adding a comment explaining that it's not used anymore > > - replacing the specific type by a raw buffer > > - updating the example code accordingly > > > > The advertised field confused users and actually never been used. So > > the wrong part here is that kernel puts something which userspace never > > used and hence this may confuse a reader of this code. > > - * @uuid: UUID of the VM. Pass to hypervisor directly. > > + * @uuid: Reserved (used to be UUID of the VM) > > If it's reserved, then don't you need to check for 0? Reserved in a way that it may content something we just don't care about. ... > > + __u8 uuid[16]; > > You just changed the type here, so what is that going to break in > userspace that depended on this being of a structure type and now it's > an array? It's the same. The previous was hidden behind additional type level. > And no other kernel changes needed? Shouldn't you warn if this field is > set? No, as pointed out in the commit message kernel never ever used this. -- With Best Regards, Andy Shevchenko