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Date:   Wed, 22 May 2019 09:15:54 +1000
From:   Paul Mackerras <paulus@ozlabs.org>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Thiago Jung Bauermann <bauerman@linux.ibm.com>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Anshuman Khandual <anshuman.linux@gmail.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Mike Anderson <andmike@linux.ibm.com>,
        Ram Pai <linuxram@us.ibm.com>,
        Claudio Carvalho <cclaudio@linux.ibm.com>
Subject: Re: [RFC PATCH 02/12] powerpc: Add support for adding an ESM blob to
 the zImage wrapper
Message-ID: <20190521231554.GB3874@blackberry>
References: <20190521044912.1375-1-bauerman@linux.ibm.com>
 <20190521044912.1375-3-bauerman@linux.ibm.com>
 <20190521051326.GC29120@lst.de>
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On Tue, May 21, 2019 at 07:13:26AM +0200, Christoph Hellwig wrote:
> On Tue, May 21, 2019 at 01:49:02AM -0300, Thiago Jung Bauermann wrote:
> > From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > 
> > For secure VMs, the signing tool will create a ticket called the "ESM blob"
> > for the Enter Secure Mode ultravisor call with the signatures of the kernel
> > and initrd among other things.
> > 
> > This adds support to the wrapper script for adding that blob via the "-e"
> > option to the zImage.pseries.
> > 
> > It also adds code to the zImage wrapper itself to retrieve and if necessary
> > relocate the blob, and pass its address to Linux via the device-tree, to be
> > later consumed by prom_init.
> 
> Where does the "BLOB" come from?  How is it licensed and how can we
> satisfy the GPL with it?

The blob is data, not code, and it will be created by a tool that will
be open source.  My understanding is that most of it will be encrypted
with a session key that is encrypted with the secret key of the
ultravisor.  Ram Pai's KVM Forum talk last year explained how this
works.

Paul.