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 E33E3C433F5 for ; Mon, 7 Feb 2022 21:58:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243377AbiBGV6u (ORCPT ); Mon, 7 Feb 2022 16:58:50 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229584AbiBGV6t (ORCPT ); Mon, 7 Feb 2022 16:58:49 -0500 Received: from mail-pj1-x102c.google.com (mail-pj1-x102c.google.com [IPv6:2607:f8b0:4864:20::102c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88765C061355 for ; Mon, 7 Feb 2022 13:58:49 -0800 (PST) Received: by mail-pj1-x102c.google.com with SMTP id qe15so4799348pjb.3 for ; Mon, 07 Feb 2022 13:58:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=mawlywQJ7By+C4lydANsL5EQYZ68ANaR80UGfPWHWA0=; b=JKY3u6RGj9vvgxsCB65Et5hqH/ceaLcskaQckSeAySE/Be9SSTHBpBAHSNSMKL2qID yGadAwamLpJTUi2zzGSU6icjLOSdDbcOCBA+SWEw4GF4P86+lm0oiUXrMw/TCNWjKCU0 LTnU7hnNvHgsPvdaq4Zj/vDsoesW+THaFJCdc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=mawlywQJ7By+C4lydANsL5EQYZ68ANaR80UGfPWHWA0=; b=a3LUndzu5PsT9tryAYQL6HowwwP1JKolhIvSobeccAHmshNhlVdQSK2UaC4LxRMhTo IdKyb5RC1ADjhguoHAR5fl/jNvl4mWynOFBgSnY7DKV7VvOzOwaFkoMWRFGv8MlZGq1p c1yREiryxv+BvWMPR5jhLj/veqo4dAazA2GNjfgNSpiqGIPf5YfcDj1X/E+9c/O9TYNW C2R+1KLitooibnQArws/B9mlG8YHJvcknYwje0OTlNndcq/vJcMNyvZX/JJomNIUgzk5 y/NmHWXxhRWQ4hh6rrw8dKCpO+QQFrpCeuG8A8Xs/AiBQ+RpcwCMBDcjcsCSaOy1iyJy aRYQ== X-Gm-Message-State: AOAM533CVcdNg8bN2ociYVFzYcRna2IsjuapgLj0wIlGNyuktpMZ2fqy EjhQTXAVDwrVVNCJRVqQSPY+lw== X-Google-Smtp-Source: ABdhPJy0AoqQe2w9LmyyFoXpDzQSjRQbdTcBCtjF6vYZ6MgOPeiHhRHaBxTOFUOM55MRrwxO/A8k/g== X-Received: by 2002:a17:902:b692:: with SMTP id c18mr1330327pls.85.1644271129101; Mon, 07 Feb 2022 13:58:49 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id 19sm301213pjb.42.2022.02.07.13.58.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Feb 2022 13:58:48 -0800 (PST) Date: Mon, 7 Feb 2022 13:58:48 -0800 From: Kees Cook To: Borislav Petkov Cc: X86 ML , LKML Subject: Re: [PATCH v2 2/6] x86/cpu: Remove "nosep" Message-ID: <202202071358.2DA81D84B@keescook> References: <20220127115626.14179-1-bp@alien8.de> <20220127115626.14179-3-bp@alien8.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220127115626.14179-3-bp@alien8.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 27, 2022 at 12:56:22PM +0100, Borislav Petkov wrote: > From: Borislav Petkov > > That chicken bit was added by > > 4f88651125e2 ("[PATCH] i386: allow disabling X86_FEATURE_SEP at boot") > > but measuring int80 vsyscall performance on 32-bit doesn't matter > anymore. > > If still needed, one can boot with > > clearcpuid=sep > > to disable that feature for testing. > > Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook -- Kees Cook