From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [RFC PATCH v6 01/26] Documentation/x86: Add CET description Date: Wed, 21 Nov 2018 08:24:33 +0100 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 Return-path: Content-Disposition: inline In-Reply-To: <16a0261fbe4b31e2f42b552d6a991a1116d398c2.camel@intel.com> Sender: linux-kernel-owner@vger.kernel.org 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 , Pa List-Id: linux-api@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