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=-2.3 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 568FCC47404 for ; Wed, 9 Oct 2019 10:50:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A8C120B7C for ; Wed, 9 Oct 2019 10:50:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730696AbfJIKus (ORCPT ); Wed, 9 Oct 2019 06:50:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34792 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726579AbfJIKus (ORCPT ); Wed, 9 Oct 2019 06:50:48 -0400 Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 30A12859FE for ; Wed, 9 Oct 2019 10:50:48 +0000 (UTC) Received: by mail-wr1-f71.google.com with SMTP id c17so915256wro.18 for ; Wed, 09 Oct 2019 03:50:48 -0700 (PDT) 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:openpgp:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Bmn/r0BsJ/ckLkCEhbCCOJ9mUA04B3GjpaUyic1itQY=; b=M8ANC+WwMGvqbVU7ujzpozTS/YE3PGt6XMsAwOin9idvzgkA5ATaK5k+8aoHa10prH mugySxZEtOt33LFJUal/sSvgEVOw4ASbY7H03pBhaC1MtLsKmU0AHiaa3ACOV2k6Yy7d xKN3EIfooIqpkYiSmLVTpynmKQxkFwoliEsHmN4x0mq4G4dhMrMQsnsXyzYM/AYVAkS+ 2O1EALH7plf1ejhaqub/DY7vaPgkdG68aSOXee1Ltd6GibZMEdMdMLNqVXEOgObWvCxg kkvsC+NJ/DQQPcWMlB2Oqi3pFABCXK3tW8ui+p1jcKI9MzwydcBeWmqNNVFZwsKSNF6G KSVA== X-Gm-Message-State: APjAAAV1wOt7M6X+5P++K3BwKLvFWszDWciwEVjTuTt2RNN3EHZPgc8J yM3x9bcKbjx5OAqBu3gAFYQCGrgzwXoWRdA4+9tU9Ec2wxeCbUIiLJRcFcKu4Ifi9JxbUkXIVBk wcOLPHpcMDYPYOmkpQhEfpjHS X-Received: by 2002:a1c:990a:: with SMTP id b10mr2059256wme.39.1570618246852; Wed, 09 Oct 2019 03:50:46 -0700 (PDT) X-Google-Smtp-Source: APXvYqwhBZEvSW0EUo/Gi5mU/wgwGG9A2c5aEjG6Esfy9ahvDY3vtdaKuBgF6plJ2JQLOMY1Q38/Fg== X-Received: by 2002:a1c:990a:: with SMTP id b10mr2059238wme.39.1570618246602; Wed, 09 Oct 2019 03:50:46 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:f4b0:55d4:57da:3527? ([2001:b07:6468:f312:f4b0:55d4:57da:3527]) by smtp.gmail.com with ESMTPSA id n1sm2469406wrg.67.2019.10.09.03.50.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Oct 2019 03:50:46 -0700 (PDT) Subject: Re: [PATCH v2 5/8] KVM: x86: Add WARNs to detect out-of-bounds register indices To: Sean Christopherson , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= Cc: Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Reto Buerki , Liran Alon References: <20190927214523.3376-1-sean.j.christopherson@intel.com> <20190927214523.3376-6-sean.j.christopherson@intel.com> From: Paolo Bonzini Openpgp: preference=signencrypt Message-ID: <9e4570a4-1da1-1109-32d3-1fba25de1963@redhat.com> Date: Wed, 9 Oct 2019 12:50:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190927214523.3376-6-sean.j.christopherson@intel.com> Content-Type: text/plain; charset=utf-8 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 27/09/19 23:45, Sean Christopherson wrote: > Open code the RIP and RSP accessors so as to avoid pointless overhead of > WARN_ON_ONCE(). Is there actually an overhead here? It is effectively WARN_ON_ONCE(0) which should be compiled out just fine. Paolo