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Subject: Re: [PATCH v2 2/6] driver core: Add common support to skip probe for
 un-authorized devices
To:     Alan Stern <stern@rowland.harvard.edu>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Kuppuswamy Sathyanarayanan 
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        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>,
        Andreas Noever <andreas.noever@gmail.com>,
        Michael Jamet <michael.jamet@intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Jason Wang <jasowang@redhat.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Kuppuswamy Sathyanarayanan <knsathya@kernel.org>,
        linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
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        "Reshetova, Elena" <elena.reshetova@intel.com>
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From:   Andi Kleen <ak@linux.intel.com>
Message-ID: <95b0e0c1-b0a2-944d-0b57-30360ac39a35@linux.intel.com>
Date:   Fri, 1 Oct 2021 08:56:31 -0700
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> Forget about trust for the moment.  Let's say the goal is to prevent
> the kernel from creating any bindings other that those in some small
> "allowed" set.  To fully specify one of the allowed bindings, you
> would have to provide both a device ID and a driver name.  But in
> practice this isn't necessary, since a device with a given ID will
> bind to only one driver in almost all cases, and hence giving just
> the device ID is enough.
>
> So to do what they want, all that's needed is to forbid any bindings
> except where the device ID is "allowed".  Or to put it another way,
> where the device's authorized flag (which can be initialized based on
> the device ID) is set.
>
> (The opposite approach, in which the drivers are "allowed" rather
> than the device IDs, apparently has already been discussed and
> rejected.  I'm not convinced that was a good decision, but...)
>
> Does this seem like a fair description of the situation?

Yes. That's roughly what the patchkit under discussion implements.


-Andi