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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 68103C433DB for ; Thu, 28 Jan 2021 18:12:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2796E64E1D for ; Thu, 28 Jan 2021 18:12:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231911AbhA1SMC (ORCPT ); Thu, 28 Jan 2021 13:12:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231528AbhA1SHa (ORCPT ); Thu, 28 Jan 2021 13:07:30 -0500 Received: from mail-pg1-x532.google.com (mail-pg1-x532.google.com [IPv6:2607:f8b0:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C05FCC061756 for ; Thu, 28 Jan 2021 10:04:55 -0800 (PST) Received: by mail-pg1-x532.google.com with SMTP id z21so4794705pgj.4 for ; Thu, 28 Jan 2021 10:04:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=l+c1w6fiiLX9kxCupjhibRajZzK8pqS48Kplrt4ilkA=; b=T3m9rl3PNu0va9eG4D3kmd7qcXfuWtB5669NgtCNk+n6h6gQt2JmZnPTA4O8551Qho uxSFmjeshjifkB0qCBN3OQyh4nyni1taYjzxvMVbZpVZag9E/lbT3dgwtJY27ooOeEXK yshp+XxJH/nqGrjxuT+1uF7RTeOLjotvJzUTNCUjB3XFmS8NVsx5K6VKE7o5YCPxZCJ1 fWQnExyY8N/F/5INWDgZXRVtBWeGqUgST0zgxR8XrsFs3sp9gRLLQxe5kCwLzffH1fHC ggR/O4dsGCsjF16YlG7+mcvCh9hseMh6kwxyPNe/I3fZhe170acMeHwDvMU2tGGtb8jE LYdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=l+c1w6fiiLX9kxCupjhibRajZzK8pqS48Kplrt4ilkA=; b=l+Sna/vnYI94uy4zmM5IJEc9U/wQ2grbf3foANBEhsHQBaNqX7Lc7RXYdA8F/7zzal CjEPPP4GTWFK8aiw3E19uvnnukxLJRsHwW3ILteZ5dfGdcDfgWX5wEdZn8MtJrFjtThL F2wPc5BASWbV+mg6KgOYDL4BQDYOP5A2GYAJlUWVyz/MD3r/6dv3fklimxUcSAmZJSA1 WIs0cD2zItRfbudNcN+E3Bn+e9f8C18DYw//Bja+3STfpkg8ophlNK+ZSp9yq/tM+UmJ fTVrAfGLyiZPwu37N0KOPQ2SoRttoQyYiO5jSwkiFCRjN/g8yxzdpGi7mTXHcGsCAHZ7 79ug== X-Gm-Message-State: AOAM530sAho/XySp8C2qQG0tmsqVWKe5iNUzFYMEBwgcACazquUGQPQq S/0HsxD8iO1za7QyGS1NxUsY4Q== X-Google-Smtp-Source: ABdhPJzgotNp2OoYBkNnmmQ6aWuLzyj9BkoBDCjhGVKIlPnXaes0QrP6iblBCQrSBBtvP0cxAs4q/Q== X-Received: by 2002:a63:3e0c:: with SMTP id l12mr667543pga.165.1611857095234; Thu, 28 Jan 2021 10:04:55 -0800 (PST) Received: from google.com ([2620:15c:f:10:91fd:c415:8a8b:ccc4]) by smtp.gmail.com with ESMTPSA id fs21sm5558089pjb.30.2021.01.28.10.04.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Jan 2021 10:04:54 -0800 (PST) Date: Thu, 28 Jan 2021 10:04:48 -0800 From: Sean Christopherson To: Paolo Bonzini Cc: Yang Weijiang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jmattson@google.com, yu.c.zhang@linux.intel.com Subject: Re: [PATCH v14 00/13] Introduce support for guest CET feature Message-ID: References: <20201106011637.14289-1-weijiang.yang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 28, 2021, Paolo Bonzini wrote: > On 06/11/20 02:16, Yang Weijiang wrote: > > Control-flow Enforcement Technology (CET) provides protection against > > Return/Jump-Oriented Programming (ROP/JOP) attack. There're two CET > > sub-features: Shadow Stack (SHSTK) and Indirect Branch Tracking (IBT). > > SHSTK is to prevent ROP programming and IBT is to prevent JOP programming. ... > I reviewed the patch and it is mostly okay. However, if I understand it > correctly, it will not do anything until host support materializes, because > otherwise XSS will be 0. IIRC, it won't even compile due to the X86_FEATURE_SHSTK and X86_FEATURE_IBT dependencies. > If this is the case, I plan to apply locally v15 and hold on it until the > host code is committed. > > Paolo >