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 75F63C47254 for ; Tue, 5 May 2020 14:59:21 +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 4C87C20675 for ; Tue, 5 May 2020 14:59:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C87C20675 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 1jVz2H-00076D-Ai; Tue, 05 May 2020 14:59:05 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jVz2G-000768-Hc for xen-devel@lists.xenproject.org; Tue, 05 May 2020 14:59:04 +0000 X-Inumbo-ID: f5ceee5a-8ee0-11ea-9887-bc764e2007e4 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id f5ceee5a-8ee0-11ea-9887-bc764e2007e4; Tue, 05 May 2020 14:59:04 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 6199DABB2; Tue, 5 May 2020 14:59:05 +0000 (UTC) Subject: Re: [PATCH 1/3] x86/mm: do not attempt to convert _PAGE_GNTTAB to a boolean To: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= , Andrew Cooper References: <20200505092454.9161-1-roger.pau@citrix.com> <20200505092454.9161-2-roger.pau@citrix.com> <20332b18-960c-a180-8150-55fae60bdc6e@suse.com> <20200505141138.GC1353@Air-de-Roger> From: Jan Beulich Message-ID: <26ec20bb-411f-c16a-40ff-417c8c5ce777@suse.com> Date: Tue, 5 May 2020 16:59:01 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200505141138.GC1353@Air-de-Roger> 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: xen-devel@lists.xenproject.org, Wei Liu Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 05.05.2020 16:11, Roger Pau Monné wrote: > On Tue, May 05, 2020 at 03:47:43PM +0200, Jan Beulich wrote: >> On 05.05.2020 11:24, Roger Pau Monne wrote: >>> Remove the conversion of _PAGE_GNTTAB to a boolean, since the and >>> operation performed afterwards will already return false if the value >>> of the macro is 0. >> >> I'm sorry, but no. The expression was put there on purpose by >> 0932210ac095 ("x86: Address "Bitwise-and with zero >> CONSTANT_EXPRESSION_RESULT" Coverity issues"), and the >> description there is clearly telling us that this wants to stay >> unless Coverity changed in the meantime. Otherwise I'm afraid >> a more elaborate solution will be needed to please both. > > Clang is fine with changing this to _PAGE_GNTTAB != 0. Would you be > OK with this approach? I'd be okay with it, but then I guess I'd prefer ... >> Or a >> more simplistic one, like using "#if _PAGE_GNTTAB" around the >> construct. > > Yes, that's the other solution I had in mind. .... this one. Let's see if Andrew has a clear opinion either way - it was him to address the original Coverity issue after all. Jan