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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 6C970C433DB for ; Fri, 29 Jan 2021 22:35:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BEACD61492 for ; Fri, 29 Jan 2021 22:35:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BEACD61492 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 133178D0002; Fri, 29 Jan 2021 17:35:06 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E4BB8D0001; Fri, 29 Jan 2021 17:35:06 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 021438D0002; Fri, 29 Jan 2021 17:35:05 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0146.hostedemail.com [216.40.44.146]) by kanga.kvack.org (Postfix) with ESMTP id E16268D0001 for ; Fri, 29 Jan 2021 17:35:05 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id A298F3622 for ; Fri, 29 Jan 2021 22:35:05 +0000 (UTC) X-FDA: 77760269370.23.kick87_56070c8275ab Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 8555937606 for ; Fri, 29 Jan 2021 22:35:05 +0000 (UTC) X-HE-Tag: kick87_56070c8275ab X-Filterd-Recvd-Size: 4362 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf05.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Jan 2021 22:35:03 +0000 (UTC) IronPort-SDR: 5VDO1LhbxrHeHw69jupLYLBaSedOgEvI+KEjAWQrnDb802cLxK54UmnsdOR8InwyibVYVpD+f0 xbL2AbSiXGaw== X-IronPort-AV: E=McAfee;i="6000,8403,9879"; a="160265042" X-IronPort-AV: E=Sophos;i="5.79,386,1602572400"; d="scan'208";a="160265042" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 14:35:02 -0800 IronPort-SDR: 8bq6hIfAMNgX92hbK4qH5hwd3yObjl/bcMQWw41W0LvWjm/TbPqtXNvZDJ35ASTSZm5aUQZoW5 0tDrkCEfMImg== X-IronPort-AV: E=Sophos;i="5.79,386,1602572400"; d="scan'208";a="411753322" Received: from yyu32-mobl1.amr.corp.intel.com (HELO [10.212.73.214]) ([10.212.73.214]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 14:35:01 -0800 Subject: Re: [NEEDS-REVIEW] [PATCH v18 05/25] x86/fpu/xstate: Introduce CET MSR and XSAVES supervisor states To: Dave Hansen , 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 , Borislav Petkov , 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 , Dave Martin , Weijiang Yang , Pengfei Xu , Andrew Cooper References: <20210127212524.10188-1-yu-cheng.yu@intel.com> <20210127212524.10188-6-yu-cheng.yu@intel.com> <7793b36e-6386-3f2e-36ca-b7ca988a88c9@intel.com> From: "Yu, Yu-cheng" Message-ID: <43f264df-2f3a-ea4c-c737-85cdc6714bd8@intel.com> Date: Fri, 29 Jan 2021 14:35:01 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: <7793b36e-6386-3f2e-36ca-b7ca988a88c9@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/29/2021 1:00 PM, Dave Hansen wrote: > On 1/27/21 1:25 PM, Yu-cheng Yu wrote: >> @@ -135,6 +135,8 @@ enum xfeature { >> #define XFEATURE_MASK_PT (1 << XFEATURE_PT_UNIMPLEMENTED_SO_FAR) >> #define XFEATURE_MASK_PKRU (1 << XFEATURE_PKRU) >> #define XFEATURE_MASK_PASID (1 << XFEATURE_PASID) >> +#define XFEATURE_MASK_CET_USER (1 << XFEATURE_CET_USER) >> +#define XFEATURE_MASK_CET_KERNEL (1 << XFEATURE_CET_KERNEL) >> #define XFEATURE_MASK_LBR (1 << XFEATURE_LBR) >> >> #define XFEATURE_MASK_FPSSE (XFEATURE_MASK_FP | XFEATURE_MASK_SSE) >> @@ -237,6 +239,23 @@ struct pkru_state { >> u32 pad; >> } __packed; >> >> +/* >> + * State component 11 is Control-flow Enforcement user states >> + */ >> +struct cet_user_state { >> + u64 user_cet; /* user control-flow settings */ >> + u64 user_ssp; /* user shadow stack pointer */ >> +}; > > Andy Cooper just mentioned on IRC about this nugget in the spec: > > XRSTORS on CET state will do reserved bit and canonicality > checks on the state in similar manner as done by the WRMSR to > these state elements. > > We're using copy_kernel_to_xregs_err(), so the #GP *should* be OK. > Could we prove this out in practice, please? > Do we want to verify that setting reserved bits in CET XSAVES states triggers GP? Then, yes, I just verified it again. Thanks for reminding. Do we have any particular case relating to this? -- Yu-cheng