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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56374C433DF for ; Mon, 6 Jul 2020 11:20:57 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 226FC2073E for ; Mon, 6 Jul 2020 11:20:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 226FC2073E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jsPAp-00018l-Op; Mon, 06 Jul 2020 11:20:35 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jsPAo-00018g-7T for xen-devel@lists.xenproject.org; Mon, 06 Jul 2020 11:20:34 +0000 X-Inumbo-ID: b49844e8-bf7a-11ea-8c67-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id b49844e8-bf7a-11ea-8c67-12813bfff9fa; Mon, 06 Jul 2020 11:20:33 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 72878AF3D; Mon, 6 Jul 2020 11:20:32 +0000 (UTC) Subject: Re: [PATCH v5 09/11] x86/domctl: add XEN_DOMCTL_vmtrace_op To: Julien Grall References: <6763525a-dca6-dfe5-b417-96e69a22d927@xen.org> <1fe71a95-1757-ca18-1d36-c3712e7b6fdf@suse.com> <7e6e4cd1-7244-243a-6af6-5c24ce24c10f@xen.org> From: Jan Beulich Message-ID: Date: Mon, 6 Jul 2020 13:20:31 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <7e6e4cd1-7244-243a-6af6-5c24ce24c10f@xen.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , tamas.lengyel@intel.com, Wei Liu , Andrew Cooper , =?UTF-8?Q?Micha=c5=82_Leszczy=c5=84ski?= , Ian Jackson , George Dunlap , luwei.kang@intel.com, xen-devel@lists.xenproject.org, =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 06.07.2020 12:38, Julien Grall wrote: > On 06/07/2020 11:37, Jan Beulich wrote: >> On 06.07.2020 12:31, Julien Grall wrote: >>> On 05/07/2020 19:55, Michał Leszczyński wrote: >>>> +/* XEN_DOMCTL_vmtrace_op: Perform VM tracing related operation */ >>>> +#if defined(__XEN__) || defined(__XEN_TOOLS__) >>>> + >>>> +struct xen_domctl_vmtrace_op { >>>> + /* IN variable */ >>>> + uint32_t cmd; >>>> +/* Enable/disable external vmtrace for given domain */ >>>> +#define XEN_DOMCTL_vmtrace_pt_enable 1 >>>> +#define XEN_DOMCTL_vmtrace_pt_disable 2 >>>> +#define XEN_DOMCTL_vmtrace_pt_get_offset 3 >>>> + domid_t domain; >>> >>> AFAICT, there is a 16-bit implicit padding here and ... >>> >>> >>>> + uint32_t vcpu; >>> >>> ... a 32-bit implicit padding here. I would suggest to make >>> the two explicit. >>> >>> We possibly want to check they are also always zero. >> >> Not just possibly imo - we should. > > I wasn't sure given that DOMCTL is not a stable interface. True; checking padding fields allows assigning meaning to them without bumping the domctl interface version. Jan