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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 166F0C433F5 for ; Fri, 1 Oct 2021 19:00:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 03CF661159 for ; Fri, 1 Oct 2021 19:00:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355960AbhJATCi (ORCPT ); Fri, 1 Oct 2021 15:02:38 -0400 Received: from netrider.rowland.org ([192.131.102.5]:34017 "HELO netrider.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1355263AbhJATCe (ORCPT ); Fri, 1 Oct 2021 15:02:34 -0400 Received: (qmail 512559 invoked by uid 1000); 1 Oct 2021 15:00:48 -0400 Date: Fri, 1 Oct 2021 15:00:48 -0400 From: Alan Stern To: Dan Williams Cc: Greg Kroah-Hartman , "Kuppuswamy, Sathyanarayanan" , "Michael S. Tsirkin" , Borislav Petkov , X86 ML , Bjorn Helgaas , Thomas Gleixner , Ingo Molnar , Andreas Noever , Michael Jamet , Yehezkel Bernat , "Rafael J . Wysocki" , Mika Westerberg , Jonathan Corbet , Jason Wang , Andi Kleen , Kuppuswamy Sathyanarayanan , Linux Kernel Mailing List , Linux PCI , USB list , virtualization@lists.linux-foundation.org Subject: Re: [PATCH v2 4/6] virtio: Initialize authorized attribute for confidential guest Message-ID: <20211001190048.GA512418@rowland.harvard.edu> References: <20210930010511.3387967-5-sathyanarayanan.kuppuswamy@linux.intel.com> <20210930065953-mutt-send-email-mst@kernel.org> <6d1e2701-5095-d110-3b0a-2697abd0c489@linux.intel.com> <1cfdce51-6bb4-f7af-a86b-5854b6737253@linux.intel.com> <20211001164533.GC505557@rowland.harvard.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 01, 2021 at 11:09:52AM -0700, Dan Williams wrote: > On Fri, Oct 1, 2021 at 9:47 AM Alan Stern wrote: > > > > On Fri, Oct 01, 2021 at 09:13:54AM -0700, Dan Williams wrote: > > > Bear with me, and perhaps it's a lack of imagination on my part, but I > > > don't see how to get to a globally generic "authorized" sysfs ABI > > > given that USB and Thunderbolt want to do bus specific actions on > > > authorization toggle events. Certainly a default generic authorized > > > attribute can be defined for all the other buses that don't have > > > legacy here, but Thunderbolt will still require support for '2' as an > > > authorized value, and USB will still want to base probe decisions on > > > the authorization state of both the usb_device and the usb_interface. > > > > The USB part isn't really accurate (I can't speak for Thunderbolt). > > When a usb_device is deauthorized, the device will be unconfigured, > > deleting all its interfaces and removing the need for any probe > > decisions about them. In other words, the probe decision for a > > usb_device or usb_interface depends only on the device's/interface's > > own authorization state. > > > > True, the interface binding code does contain a test of the device's > > authorization setting. That test is redundant and can be removed. > > > > The actions that USB wants to take on authorization toggle events for > > usb_devices are: for authorize, select and install a configuration; > > for deauthorize, unconfigure the device. Each of these could be > > handled simply enough just by binding/unbinding the device. (There > > is some special code for handling wireless USB devices, but wireless > > USB is now defunct.) > > Ah, so are you saying that it would be sufficient for USB if the > generic authorized implementation did something like: > > dev->authorized = 1; > device_attach(dev); > > ...for the authorize case, and: > > dev->authorize = 0; > device_release_driver(dev); > > ...for the deauthorize case? Yes, I think so. But I haven't tried making this change to test and see what really happens. Alan Stern