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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 664DDC432BE for ; Wed, 4 Aug 2021 21:07:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4064860F58 for ; Wed, 4 Aug 2021 21:07:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238844AbhHDVIH (ORCPT ); Wed, 4 Aug 2021 17:08:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33612 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231602AbhHDVIH (ORCPT ); Wed, 4 Aug 2021 17:08:07 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E4A18C0613D5; Wed, 4 Aug 2021 14:07:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=bpxyDpnvly9eIlMQTFPJ1aBcN9lOvzkoVYTJFUDJnqo=; b=iLoMBWKjIEusVQoTWW/PDbf4E6 UpBvg0/6a7I3wA1o0hOk+3nIixZMjbuU7AvdPcOKwOHcxBJJxKPbw+sVrBvYmdHKAJC1+7ivKtRCW kw51BIbzdxEgabH2EqeEkojnf/p8N6qRwm3jfLoqiPMn8bw2ImSKR1bKk7RxwBR0/1nD2ktoveeXy uw3t0cctv1UXtLL2gLzkOW3aGA4l1asOPtBeBC/leUQBRFaTPM5o48yWRjN2ja0OMNj7WPlSdJNQM QChffB6AwMrUaPh+iaThHIffvV/O4P3Wk29gLPuGRqg/qsmyay8NgDlcmM5YfEFD+KLW87Vjcrsla 9NH6/B2g==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mBO6W-006IQp-Ga; Wed, 04 Aug 2021 21:07:16 +0000 Date: Wed, 4 Aug 2021 22:07:08 +0100 From: Matthew Wilcox To: Dan Williams Cc: Greg Kroah-Hartman , Kuppuswamy Sathyanarayanan , "Rafael J . Wysocki" , Jonathan Corbet , Andi Kleen , Kuppuswamy Sathyanarayanan , Linux Kernel Mailing List , Linux Doc Mailing List Subject: Re: [PATCH v1] driver: base: Add driver filter support Message-ID: References: <20210804174322.2898409-1-sathyanarayanan.kuppuswamy@linux.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 Wed, Aug 04, 2021 at 01:11:27PM -0700, Dan Williams wrote: > On Wed, Aug 4, 2021 at 12:29 PM Greg Kroah-Hartman > wrote: > > Why not just make distros that want to support this type of platform, > > also provide these tiny kernel images? Why are you pushing this work on > > the kernel community instead? > > In fact, these questions are where I started when first encountering > this proposal. Andi has addressed the single kernel image constraint, > but I want to pick up on this "pushing work to the kernel community" > contention. The small list of vetted drivers that a TDX guest needs > will be built-in and maintained in the kernel by the protected guest > developer community, so no "pushing work" there. However, given that > any driver disable mechanism needs to touch the driver core I > advocated to go ahead and make this a general purpose capability to > pick up where this [1] conversation left off. I.e. a general facility > for the corner cases that modprobe and kernel config policy can not > reach. Corner cases like VMM attacking the VM, or broken hardware with > a built-in driver that can't be unbound after the fact. I don't understand how this defends against a hypervisor attacking a guest. If the hardware exists, the hypervisor can access it, regardless of whether the driver is default-disabled by configuration.