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 261F0C433EF for ; Thu, 30 Sep 2021 15:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10D8661994 for ; Thu, 30 Sep 2021 15:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352041AbhI3PCA (ORCPT ); Thu, 30 Sep 2021 11:02:00 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:52749 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352104AbhI3PB6 (ORCPT ); Thu, 30 Sep 2021 11:01:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1633014015; 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: in-reply-to:in-reply-to:references:references; bh=0Uhm+QYM76Q/NUVbbvm//7rv1aKv+wtBYWvx/Vlkg4E=; b=SucXab1gQHa/Umh2MgoDVgzG1AhGw+EfI0kz421wbzXrJWInvhzsbL41RH7OlQ4oDVK/iP qt7On/M8ibIU5ucS45aNMLALZ1Pxrjxj07H8YNexME27WVKIzIo0Ob6gYB5HWy30LHAfuD SUq6s7oybrFwysJH8XMfkYxfpdJNQeU= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-491-Bp6giNe8NuiUEipQm6xJAA-1; Thu, 30 Sep 2021 11:00:14 -0400 X-MC-Unique: Bp6giNe8NuiUEipQm6xJAA-1 Received: by mail-ed1-f72.google.com with SMTP id 14-20020a508e4e000000b003d84544f33eso6662321edx.2 for ; Thu, 30 Sep 2021 08:00:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=0Uhm+QYM76Q/NUVbbvm//7rv1aKv+wtBYWvx/Vlkg4E=; b=cU+SHstiUlLmLqjWyUnG/gEpdtBTyXb9TzRI7Pt2gpsjcJ730bRUloUOQvK2r/yVH8 OLS0FqD3ueyZhzOPfwhPpIGEdPacgHcqCTju1bSnOo3HlGVhtqp6w8Hq6Czfoo+hFgsF CwutTl+sI3w3LbJ+1ssN19eh15F8DSAHdAHFRxr0X4UEsmKNLJ/NsxznWPlwu5uCnDiB zyiClg62aJzu30cWMfEX5eY30KD135Vmfp8G/+gBwG0X+BKJ94SfW9lNIVb4Oy6mnWkj CcgerKgXxz0Smc5lsZYlNtaG6Mgb6aAb9qGcfcT4vkvlF2e67F0dYPH1bN7nhsgbQ2Hl ilnA== X-Gm-Message-State: AOAM531MmkmELxHZZfwzhpxWOPsDQYqPEgDKYMYTSpzoyVxgTQh4kKjb S7qwoCpHEzkb6tYfMSg9OaXwTlTjNiS3Ycn3gXyX7UcCurMnWS3KeWGuNN8L28GrS2tPCj2qwyN yZZyPrUKgihpj+X3nzETH X-Received: by 2002:a17:906:1b08:: with SMTP id o8mr7415459ejg.21.1633014012970; Thu, 30 Sep 2021 08:00:12 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzz5aESHhTZJzzyTWIqcWelf63OI2y13i3Gz90wHayn2gr4CKl6nhaZlq4TjwGKZXxkJMK2Wg== X-Received: by 2002:a17:906:1b08:: with SMTP id o8mr7415439ejg.21.1633014012775; Thu, 30 Sep 2021 08:00:12 -0700 (PDT) Received: from redhat.com ([2.55.134.220]) by smtp.gmail.com with ESMTPSA id l10sm1630936edr.14.2021.09.30.08.00.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 30 Sep 2021 08:00:12 -0700 (PDT) Date: Thu, 30 Sep 2021 11:00:07 -0400 From: "Michael S. Tsirkin" To: Greg Kroah-Hartman Cc: Kuppuswamy Sathyanarayanan , Borislav Petkov , x86@kernel.org, Bjorn Helgaas , Thomas Gleixner , Ingo Molnar , Andreas Noever , Michael Jamet , Yehezkel Bernat , "Rafael J . Wysocki" , Mika Westerberg , Jonathan Corbet , Jason Wang , Dan Williams , Andi Kleen , Kuppuswamy Sathyanarayanan , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-usb@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH v2 2/6] driver core: Add common support to skip probe for un-authorized devices Message-ID: <20210930105852-mutt-send-email-mst@kernel.org> References: <20210930010511.3387967-1-sathyanarayanan.kuppuswamy@linux.intel.com> <20210930010511.3387967-3-sathyanarayanan.kuppuswamy@linux.intel.com> <20210930065807-mutt-send-email-mst@kernel.org> <20210930103537-mutt-send-email-mst@kernel.org> 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-pci@vger.kernel.org On Thu, Sep 30, 2021 at 04:49:23PM +0200, Greg Kroah-Hartman wrote: > On Thu, Sep 30, 2021 at 10:38:42AM -0400, Michael S. Tsirkin wrote: > > On Thu, Sep 30, 2021 at 03:52:52PM +0200, Greg Kroah-Hartman wrote: > > > On Thu, Sep 30, 2021 at 06:59:36AM -0400, Michael S. Tsirkin wrote: > > > > On Wed, Sep 29, 2021 at 06:05:07PM -0700, Kuppuswamy Sathyanarayanan wrote: > > > > > While the common case for device-authorization is to skip probe of > > > > > unauthorized devices, some buses may still want to emit a message on > > > > > probe failure (Thunderbolt), or base probe failures on the > > > > > authorization status of a related device like a parent (USB). So add > > > > > an option (has_probe_authorization) in struct bus_type for the bus > > > > > driver to own probe authorization policy. > > > > > > > > > > Reviewed-by: Dan Williams > > > > > Signed-off-by: Kuppuswamy Sathyanarayanan > > > > > > > > > > > > > > > > So what e.g. the PCI patch > > > > https://lore.kernel.org/all/CACK8Z6E8pjVeC934oFgr=VB3pULx_GyT2NkzAogdRQJ9TKSX9A@mail.gmail.com/ > > > > actually proposes is a list of > > > > allowed drivers, not devices. Doing it at the device level > > > > has disadvantages, for example some devices might have a legacy > > > > unsafe driver, or an out of tree driver. It also does not > > > > address drivers that poke at hardware during init. > > > > > > Doing it at a device level is the only sane way to do this. > > > > > > A user needs to say "this device is allowed to be controlled by this > > > driver". This is the trust model that USB has had for over a decade and > > > what thunderbolt also has. > > > > > > > Accordingly, I think the right thing to do is to skip > > > > driver init for disallowed drivers, not skip probe > > > > for specific devices. > > > > > > What do you mean by "driver init"? module_init()? > > > > > > No driver should be touching hardware in their module init call. They > > > should only be touching it in the probe callback as that is the only > > > time they are ever allowed to talk to hardware. Specifically the device > > > that has been handed to them. > > > > > > If there are in-kernel PCI drivers that do not do this, they need to be > > > fixed today. > > > > > > We don't care about out-of-tree drivers for obvious reasons that we have > > > no control over them. > > > > > > thanks, > > > > > > greg k-h > > > > Well talk to Andi about it pls :) > > https://lore.kernel.org/r/ad1e41d1-3f4e-8982-16ea-18a3b2c04019%40linux.intel.com > > As Alan said, the minute you allow any driver to get into your kernel, > it can do anything it wants to. > > So just don't allow drivers to be added to your kernel if you care about > these things. The system owner has that mechanism today. > > thanks, > > greg k-h The "it" that I referred to is the claim that no driver should be touching hardware in their module init call. Andi seems to think such drivers are worth working around with a special remap API. -- MST