From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-1.8 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, FSL_HELO_FAKE,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 7AEC37D089 for ; Wed, 21 Nov 2018 07:24:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726090AbeKUR6A (ORCPT ); Wed, 21 Nov 2018 12:58:00 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:44036 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726001AbeKUR57 (ORCPT ); Wed, 21 Nov 2018 12:57:59 -0500 Received: by mail-wr1-f67.google.com with SMTP id z5so193869wrt.11; Tue, 20 Nov 2018 23:24:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=HL9Ofpo+fXfQMYMg8SkT8OKAVFuPSOM2FApHtnL7joA=; b=HQtEe05+JNqnFWcP7fVfvwRmTooqFIUz1QZ64fxNee/GNZgkHW6U2zEGNDTlcY8wrx R5ldfP3XQO8I18veGbHr6lym5r+TPCAY2edV3uwW6zX1qjXIC62En958ZFq6QXjVdjuw 7b5gbVugHZH9hAn+Yhtbzt3VC+B7nSeXHhmRdT9bs6l0ujy3qTovBj3FuXcg1pUC0ahp 2eehGmW17fUT9PEU89bIXUqquLOPzZcLAyIdjbZL35OcujvqlIe3x3dKTk+Qg7qTmj14 lvfY4j2+1nZMOID8xpExGOLtahejl1/emCS/siA8DBuh2W9XgHKNAv7wre+OHShc7uWf 9KSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=HL9Ofpo+fXfQMYMg8SkT8OKAVFuPSOM2FApHtnL7joA=; b=PDkPqa+toECafEKKKqp/wjARf838cjKjacUlRhx4DUNHCU6h5zca6XtlYSHPIO4JOt 2EVbYDbl72+K4jv65oEWZIJozQ0KOyr7Hy0SX/v7mfDSYWXUK8uR5sfCHyS/N0CKWefM 7TTxMkqjUsPFaB05gY1v1pRJeBgzbmTJi5DbazzQ7IRmI8EuXfvVQZHNiZaNxz+29tT2 ehA/y98iq63OAIvD5hQdP7/49AAP0U15uc9NYNHPwwFj41DPalpbNBcotLdu0rlFLUy+ /qKAAEH75MhJ1pQMEFmdn77lQLv17we4d3JuJ/8X5dnVHDXVqplpoXtGvqU6q9RL523Q xtvQ== X-Gm-Message-State: AA+aEWbxtSWq/qHSrw+VjdjET59GKYd9auB8dOWW7sftEwC52U+PxrJN GHCwv5rCLVBKsFUJnsscwps= X-Google-Smtp-Source: AFSGD/XN54iEj+GQABK7q+4u5AwT5JgdjtepjO6EJpYdU+3cvVEzWrHBU0npT+mhud40gOD7tG79Vw== X-Received: by 2002:adf:a109:: with SMTP id o9-v6mr4497277wro.169.1542785077292; Tue, 20 Nov 2018 23:24:37 -0800 (PST) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id t5sm70496wmg.43.2018.11.20.23.24.35 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 20 Nov 2018 23:24:36 -0800 (PST) Date: Wed, 21 Nov 2018 08:24:33 +0100 From: Ingo Molnar To: Yu-cheng Yu Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue Subject: Re: [RFC PATCH v6 01/26] Documentation/x86: Add CET description Message-ID: <20181121072433.GA56599@gmail.com> References: <20181119214809.6086-1-yu-cheng.yu@intel.com> <20181119214809.6086-2-yu-cheng.yu@intel.com> <20181120095253.GA119911@gmail.com> <16a0261fbe4b31e2f42b552d6a991a1116d398c2.camel@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16a0261fbe4b31e2f42b552d6a991a1116d398c2.camel@intel.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org * Yu-cheng Yu wrote: > On Tue, 2018-11-20 at 10:52 +0100, Ingo Molnar wrote: > > * Yu-cheng Yu wrote: > > > > > +X86 Documentation > > > [...] > > > + > > > +At run time, /proc/cpuinfo shows the availability of SHSTK and IBT. > > > > What is the rough expected performance impact of CET on average function > > call frequency user applications and the kernel itself? > > I don't have any conclusive numbers yet; but since currently only user-mode > protection is implemented, I suspect any impact would be most likely to the > application. The kernel would spend some small amount of time on the setup of > CET. This is horribly vague. Thanks, Ingo