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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5643AC433FE for ; Mon, 3 Oct 2022 17:26:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D7CA38E0001; Mon, 3 Oct 2022 13:26:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D2B846B0073; Mon, 3 Oct 2022 13:26:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BF3DE8E0001; Mon, 3 Oct 2022 13:26:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id AA9FF6B0071 for ; Mon, 3 Oct 2022 13:26:53 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 728F580589 for ; Mon, 3 Oct 2022 17:26:53 +0000 (UTC) X-FDA: 79980318306.12.7D26BD0 Received: from mail-pj1-f54.google.com (mail-pj1-f54.google.com [209.85.216.54]) by imf05.hostedemail.com (Postfix) with ESMTP id ED4B8100013 for ; Mon, 3 Oct 2022 17:26:52 +0000 (UTC) Received: by mail-pj1-f54.google.com with SMTP id g1-20020a17090a708100b00203c1c66ae3so10531621pjk.2 for ; Mon, 03 Oct 2022 10:26:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date; bh=ABM+NW6fVFThNfu9rqzeSH+UmSPvsbfFChaihmMOzbw=; b=gWyi5FlTflhv4r8w9GnrNfmHyxVxQrP7zj24MK1x/79q55HKbmaJ624vadwY9ZV8Au REnDn+9tMWfFBQQBccazjx5vZNBGXA9jfxCFhdR2RW7Ni1H2jSfv3BaACt3a0Jb9xc+G SqZMLFdOyjCtpNMjWZzY5MBW9r7I1IvM7EpSo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=ABM+NW6fVFThNfu9rqzeSH+UmSPvsbfFChaihmMOzbw=; b=T4bEzR/3A0tlUxnnGL6DF6cfVyFTNGCqubyM4eG9rTB+Xm+J8d3jz1o12W9ksnp2ul eQ7ta1N+RAkt6JNl5RE7TiFCcugNv6zItV0m+zzp3wDFefbgdKl8GlPs46vx46U36ab+ 1bduDYnq+4lK1qBSriPTPSZmBxhU6DHZyR8arHJNHoPVqEWPcgYKcda48Mt0qcjBS/4E 5xUcaFBTzr/VvHSKv+ld7w/8PpGgo0GHzKQPVvRIjiAMPAknFQIaDQDuSVtpA76lIcyg u4qSptzqbr2u9wIJ7nZ0jCyp8tyads4m/An9Okcr/T72KXTBoT3nwbnSGsjNhC4ubAQy JbYw== X-Gm-Message-State: ACrzQf02sracg30iBM2cyss4leSTFsH9qRPgkxrZzejHbRfG3ksbuNdI 3FETc+d6li0Ihfc2j3LXoZ9rYw== X-Google-Smtp-Source: AMsMyM5wNcp5rTMmeLf+u/bHVgBxlTjtCbpJ/kd4PG5p9soWUXZV+BBgGjn7+y+I34j7N+HHikbN6g== X-Received: by 2002:a17:903:32d1:b0:178:1cf0:5081 with SMTP id i17-20020a17090332d100b001781cf05081mr23742922plr.54.1664818011913; Mon, 03 Oct 2022 10:26:51 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id k12-20020a170902ce0c00b00176e6f553efsm7464071plg.84.2022.10.03.10.26.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 03 Oct 2022 10:26:51 -0700 (PDT) Date: Mon, 3 Oct 2022 10:26:50 -0700 From: Kees Cook To: Rick Edgecombe 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 , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H . J . Lu" , Jann Horn , Jonathan Corbet , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V . Shankar" , Weijiang Yang , "Kirill A . Shutemov" , joao.moreira@intel.com, John Allen , kcc@google.com, eranian@google.com, rppt@kernel.org, jamorris@linux.microsoft.com, dethoma@microsoft.com, Yu-cheng Yu Subject: Re: [PATCH v2 03/39] x86/cpufeatures: Add CPU feature flags for shadow stacks Message-ID: <202210031026.22DBF47CCD@keescook> References: <20220929222936.14584-1-rick.p.edgecombe@intel.com> <20220929222936.14584-4-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220929222936.14584-4-rick.p.edgecombe@intel.com> ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664818013; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ABM+NW6fVFThNfu9rqzeSH+UmSPvsbfFChaihmMOzbw=; b=bwB67KPa1XQRCAFqS2wtFSWKdlm4mUYdPr7+kXf6E+UNiLi8k/9bjRHZRO6GOLG4xBIwNH JOABWNAxd56YCYeY4ijo/3mLzmKAOmRLODc90Im0Bk811TyL8hMAasZEkyNPto6YVGmdJ/ 5E1qj51zlmMz8JrbeIXmV70jAec9EH4= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=gWyi5FlT; spf=pass (imf05.hostedemail.com: domain of keescook@chromium.org designates 209.85.216.54 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664818013; a=rsa-sha256; cv=none; b=00L2GDqQU3BqC3WDY6EBR4u7fYirqXAnm8X13LCTe3I2FpoHyFe4gaeZzcO0hUhU/a9dml +qU+xmjCGO1X2kIImMfr58gLPcRm9ZqP7iEPl94f3o/KYwh2vezc0Z1HzsL9g8iEMjy7PG 8STwkCK8yu+eeTkkQCTF2vMWi0mcqd8= X-Rspamd-Queue-Id: ED4B8100013 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=chromium.org header.s=google header.b=gWyi5FlT; spf=pass (imf05.hostedemail.com: domain of keescook@chromium.org designates 209.85.216.54 as permitted sender) smtp.mailfrom=keescook@chromium.org; dmarc=pass (policy=none) header.from=chromium.org X-Rspamd-Server: rspam06 X-Rspam-User: X-Stat-Signature: rm4uwx675haoq9ag8u37o9top1ndomk3 X-HE-Tag: 1664818012-553511 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 Thu, Sep 29, 2022 at 03:29:00PM -0700, Rick Edgecombe wrote: > From: Yu-cheng Yu > > The Control-Flow Enforcement Technology contains two related features, > one of which is Shadow Stacks. Future patches will utilize this feature > for shadow stack support in KVM, so add a CPU feature flags for Shadow > Stacks (CPUID.(EAX=7,ECX=0):ECX[bit 7]). > > To protect shadow stack state from malicious modification, the registers > are only accessible in supervisor mode. This implementation > context-switches the registers with XSAVES. Make X86_FEATURE_SHSTK depend > on XSAVES. > > Signed-off-by: Yu-cheng Yu Reviewed-by: Kees Cook -- Kees Cook