Re: [Qemu-devel] [PATCH 1/7] nios2: Add disas entries

[Eric Blake <eblake@redhat.com>]

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On 06/13/2016 02:11 PM, Sandra Loosemore wrote:

>>> This is a non-starter.  Qemu is a GPLv2-only project because of some of
>>> the files it has already borrowed from other places, so we CANNOT use
>>> GPLv3 files.  You'll have to implement this from scratch, or pull from
>>> binutils at the point prior to where upstream binutils upgraded to
>>> GPLv3.
>>>
>> Ouch, I see. I hope Sandra (on CC) might have some idea how to best go
>> about this licensing thing. I briefly checked and the nios2 stuff landed
>> in binutils under gpl3 already.
> 
> Hmmmm.  Upstream binutils was already using GPLv3 at the time the nios2
> support was contributed.  I believe Altera's original out-of-tree patch
> set was GPLv2 but it is extremely bit-rotten at this point and doesn't
> include the new R2 instruction set or abstractions to support multiple
> ISA variants (I had to do a lot of refactoring of the old
> opcodes/disassembler support that amounted to almost a complete
> rewrite).  I could look into whether Mentor Graphics could relicense our
> changes under GPLv2, but I'm not sure that would be possible or helpful
> given that both Altera and Mentor have already assigned copyright to the
> FSF?  I'm not a legal expert.  :-(

I'm not a copyright lawyer.  However, I _do_ know that when you assign
copyright to the FSF, you retain the right as original author to
relicense _your_ contribution however you see fit.  That is, if the
authors of ALL patches to that file agree (or if you can filter out any
patches from other authors and get back to a version of the file that
just consenting authors wrote), you can declare that your contributions
are GPLv2+, which will make them usable in qemu under GPLv2+, while
still remaining GPLv3+ in binutils.  And you may want to consult with an
actual lawyer before attempting anything that might cause legal issues.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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