Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752681AbdGYPN1 (ORCPT ); Tue, 25 Jul 2017 11:13:27 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:49176 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752568AbdGYPNY (ORCPT ); Tue, 25 Jul 2017 11:13:24 -0400 Date: Tue, 25 Jul 2017 16:12:20 +0100 From: Mark Rutland To: Li Kun Cc: linux-arm-kernel@lists.infradead.org, arnd@arndb.de, catalin.marinas@arm.com, christoffer.dall@linaro.org, Dave.Martin@arm.com, jiong.wang@arm.com, kvmarm@lists.cs.columbia.edu, linux-arch@vger.kernel.org, marc.zyngier@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, yao.qi@arm.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com Subject: Re: [kernel-hardening] [PATCH 00/11] ARMv8.3 pointer authentication userspace support Message-ID: <20170725151220.GB20857@leverpostej> References: <1500480092-28480-1-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 751 Lines: 23 On Tue, Jul 25, 2017 at 10:12:24PM +0800, Li Kun wrote: > Hi Mark, Hi, > Could you please give us some information about the impact to > performance to help us evaluating the influence to the system? I'm afraid I don't have any performance details to share, as this series has been developed and tested using models, and the performance impact of pointer authentication will be very much dependent on the microarchitecture. I have assumed that this shouldn't regress performance on systems without pointer authentication functionality, but I haven't yet attempted to verify that. >From this series, I'd expect the largest cost to be the semi-lazy KVM context-switch, for guests which are continuously using pointer authentication. Thanks, Mark.