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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 996B4C4332F for ; Fri, 14 Oct 2022 16:21:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230136AbiJNQU7 (ORCPT ); Fri, 14 Oct 2022 12:20:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229672AbiJNQUx (ORCPT ); Fri, 14 Oct 2022 12:20:53 -0400 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7C3A7E4C21; Fri, 14 Oct 2022 09:20:49 -0700 (PDT) Received: from zn.tnic (p200300ea9733e7ed329c23fffea6a903.dip0.t-ipconnect.de [IPv6:2003:ea:9733:e7ed:329c:23ff:fea6:a903]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 309AA1EC064E; Fri, 14 Oct 2022 18:20:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1665764444; h=from:from: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; bh=/Wh0zbFGTIbft2gDvKR16DzRYnJEB/RKZdQTzdqS+mY=; b=ph9EsHV1y0KX4HYpc4X1/DaIFwwH07WDdjPORZ/cMJunsKSVMNLOUJerlurPUwYFdShdbq hM6gbuhSJQA9gypG8KSA/BUTXwUIMb9AeMGlJ0BFu7DaYO18AYtvcvlpG1NMdPTlaX7cwf wWdoa6T2PDBLrPzaaR1c8h+EZX7yIt0= Date: Fri, 14 Oct 2022 18:20:38 +0200 From: Borislav Petkov 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 , 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" , 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: 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=utf-8 Content-Disposition: inline In-Reply-To: <20220929222936.14584-4-rick.p.edgecombe@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > Co-developed-by: Rick Edgecombe > Signed-off-by: Rick Edgecombe > Cc: Kees Cook Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette