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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 BB008C33CB3 for ; Wed, 15 Jan 2020 18:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 959A32187F for ; Wed, 15 Jan 2020 18:20:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="e3fFBVzO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729256AbgAOSU2 (ORCPT ); Wed, 15 Jan 2020 13:20:28 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:52507 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729016AbgAOSU2 (ORCPT ); Wed, 15 Jan 2020 13:20:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579112426; h=from:from: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=17zGvszpS2X4BFkl2CiCggkEpVm2B9z6sEshLBKqEMs=; b=e3fFBVzOGQ2wSbLrL/7aqB7uE6xZP2JesqEilcrcdvH6kHNchFe79DSCK8K0I3GkMHXFR+ J9danh0Wr7Uumhy9U6LJ7+XG4EXy2unX1O/kseicAdfRZ0vDFLUkIoae+fWTp850Sn6rRp 1HrgeeZwRADkpFPn2BIBRiqh+HkrX1s= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-373-OItrfQ9xOhixuAew4QYfbA-1; Wed, 15 Jan 2020 13:20:25 -0500 X-MC-Unique: OItrfQ9xOhixuAew4QYfbA-1 Received: by mail-wr1-f69.google.com with SMTP id v17so8256786wrm.17 for ; Wed, 15 Jan 2020 10:20:25 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=17zGvszpS2X4BFkl2CiCggkEpVm2B9z6sEshLBKqEMs=; b=fd8RZh1UnDrnaGAFmqkkiqKvxTLjCkKk+xZv2kKyAY0oID1OQ4cHwJIUehWMm2fur4 WCXoR46ZC92gb6hxt9eCo22RaTV7QHjWwqialx29a7Jx7//9X4gj35APW2EM5nUkQdpS vXHvyVX2MBFFbRyOMqdMeMAC7Cj8PChpb5fiFia2WClkcWUgvkINerG2RLpwTCwq2tw8 EYq+5ZGxr7jKAuOC2ZTekph+kRcuQx0F1fxRnkGHzO26KUi6JZEHgSaFgNm+8Twsq0KI IPxzeDnZTWVW4dWYggcmAxaYNpnucg6DYoNNxywtdU+NhsaHroOdfEutq16xMJa2JqFe 3T1w== X-Gm-Message-State: APjAAAUsihaRPQNdY63/Zw01ikKsojJATvOzMoXkQpIr8mGvS4xDYp9Q jT1uc+HSbsFmUHQgZxfymnWt//M5nQAx4yJ0JkW0cvcEJO+Iuwt1lVdsnkKY/8PzjAtxl7sddc8 yYsGrVJRvHG3Hf2Io6ExgAsir X-Received: by 2002:adf:eb46:: with SMTP id u6mr33317278wrn.239.1579112423904; Wed, 15 Jan 2020 10:20:23 -0800 (PST) X-Google-Smtp-Source: APXvYqw/Qyejk/Pe57hiihIWH7LtW6xhsVMRE5PFvyRvUxM72lwLh4/4yWAz6JdsH05250/GZ594wQ== X-Received: by 2002:adf:eb46:: with SMTP id u6mr33317258wrn.239.1579112423623; Wed, 15 Jan 2020 10:20:23 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:436:e17d:1fd9:d92a? ([2001:b07:6468:f312:436:e17d:1fd9:d92a]) by smtp.gmail.com with ESMTPSA id e6sm26800599wru.44.2020.01.15.10.20.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Jan 2020 10:20:22 -0800 (PST) Subject: Re: [PATCH] KVM: x86/mmu: Fix a benign Bitwise vs. Logical OR mixup To: Sean Christopherson , Arvind Sankar Cc: David Laight , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20200108001859.25254-1-sean.j.christopherson@intel.com> <20200109152629.GA25610@rani.riverdale.lan> <20200109163624.GA15001@linux.intel.com> From: Paolo Bonzini Message-ID: <41a2328e-a64a-0131-920e-06328305919d@redhat.com> Date: Wed, 15 Jan 2020 19:20:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20200109163624.GA15001@linux.intel.com> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/01/20 17:36, Sean Christopherson wrote: >>> You also don't want to convert the expression result to zero. >> The function is static inline bool, so it's almost certainly a mistake >> originally. The != 0 is superfluous, but this will get inlined anyway. > Ya, the bitwise-OR was added in commit 25d92081ae2f ("nEPT: Add nEPT > violation/misconfigration support"), and AFAICT it's unintentional. It may not be intentional in this case, but it's certainly the kind of code that I would have fun writing. :) Paolo