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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 ED770C433DB for ; Thu, 28 Jan 2021 18:12:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9A1F64E1D for ; Thu, 28 Jan 2021 18:12:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231956AbhA1SMI (ORCPT ); Thu, 28 Jan 2021 13:12:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:38055 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231536AbhA1SHs (ORCPT ); Thu, 28 Jan 2021 13:07:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611857180; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rLpGMEsWUFtvOGdp4Bl4045lZDRmMlzwwfBz1eKojT4=; b=hPCUs+7FhA9REhCz1wtcNERYwYaz1B1+re17nZGRTEk8uBr8W5NFHORZxyM70bHnTBtypD rFA2LaJRnZqndY0ouwCGJ64tkhvJaSU2K3EphIZANQKovNoNo+6kYWwU871CDVC52N7T3F pP/aYC0QJATqHzAMY2haOaBcAt6+ods= Received: from mail-ed1-f70.google.com (mail-ed1-f70.google.com [209.85.208.70]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-199-z5PpwGCAPn26VFYs_O4BIw-1; Thu, 28 Jan 2021 13:06:18 -0500 X-MC-Unique: z5PpwGCAPn26VFYs_O4BIw-1 Received: by mail-ed1-f70.google.com with SMTP id y6so3572141edc.17 for ; Thu, 28 Jan 2021 10:06:18 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rLpGMEsWUFtvOGdp4Bl4045lZDRmMlzwwfBz1eKojT4=; b=Y8TMrqytg+iKlL41mYOcaQqjOpvrArqZi61ZOZJYZguEHJtr5iqrmuCMhRTi70Wy/6 SlDJqPWiYIoA35ZNmQJXSe84co4ckGnw0z/Id+tE5stpHg76ZrcD9Tl/2Gbgj9Fa9Whe UcGKs4wk1Og5n8xWNAmwRWHhG8FxGYiU8kzKEasX4CCMyGIe7UhBx+cdHr7c7runrtRB xs0x8LrF1gpR+EQb0oUWXD6hYlkvYh5Qy4vQlVwpfZ5eykgHlNT8hx1EQ+a4P38Aurt3 WVwNMeBsFqV9sM5Edl1FU4uIfJCZX9X0Bnrhq6WsQ4v/NoovDqHsmkBj51RHFoxpD27v Rv5A== X-Gm-Message-State: AOAM530G6anUp3f7PRWpm21+NyBKxJH3KgWAwJCCeV/61PqOfBmxJGK6 1wjeLstFZLr0yAWZr/PbKd2tzAXb6W6nr+rocJ63uutE5s+A65p+WoOJzzwLOUM9N8rsSH8c53u THEUuj8o4hFdpeg+hQpIsK5vn X-Received: by 2002:a17:906:a48:: with SMTP id x8mr626106ejf.444.1611857177303; Thu, 28 Jan 2021 10:06:17 -0800 (PST) X-Google-Smtp-Source: ABdhPJzHfUKevTd/4l9Cq7zXQgMsfc9UehVxY6ry045/wWY1PjhtT8vA4WzaKXdxYCtMCcp0FrzTOA== X-Received: by 2002:a17:906:a48:: with SMTP id x8mr626095ejf.444.1611857177168; Thu, 28 Jan 2021 10:06:17 -0800 (PST) Received: from ?IPv6:2001:b07:6468:f312:c8dd:75d4:99ab:290a? ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id p15sm2652745ejd.121.2021.01.28.10.06.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 Jan 2021 10:06:16 -0800 (PST) Subject: Re: [PATCH v14 00/13] Introduce support for guest CET feature To: Sean Christopherson Cc: Yang Weijiang , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, jmattson@google.com, yu.c.zhang@linux.intel.com References: <20201106011637.14289-1-weijiang.yang@intel.com> From: Paolo Bonzini Message-ID: <32c9cdf7-7432-1212-2fe4-fe35ad27105a@redhat.com> Date: Thu, 28 Jan 2021 19:06:13 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/01/21 19:04, Sean Christopherson wrote: > 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. Of course, but if that was the only issue I would sort it out with Boris as usual. OTOH if it is dead code I won't push it to Linus. Paolo >> If this is the case, I plan to apply locally v15 and hold on it until the >> host code is committed. >> >> Paolo >> >