Re: [Qemu-devel] CMSIS SVD based peripheral definitions

[Dr. David Alan Gilbert]

* Peter Maydell (address@hidden) wrote:
> On 9 January 2017 at 17:47, Liviu Ionescu <address@hidden> wrote:
> > I can't dispute this, but does't the GPLv2 requirements apply to
> > the qemu executable only? my JSON files are not compiled into the
> > binary, but are data files, read by the executable when required.
> > and anyway, the original license covers the original XML files,
> > mine are not only JSON, but are also slightly different.
> 
> I'm not a lawyer, and this isn't legal advice, but merely
> my own opinion:
>  (1) if you're reading in the data files at runtime then there's
> a spectrum between "just reading data provided by the user which
> didn't ship with QEMU, and QEMU works OK without this particular
> data" (clearly OK) and "reading data that shipped with QEMU
> and where QEMU won't work at all without it" (the data files
> are clearly part of the program as a whole and the GPL
> applies to them even if they don't happen to be binaries);
> where you stand legally probably depends on where on the
> spectrum you are.
> 
>  (2) your JSON files are a derived work from the original
> XML, so the license of those XML files (whatever it is) still
> applies to them. Making modifications or a mechanical
> transformation of the original files is not sufficient to
> allow you to discard the license...
> 
> With my project maintainer hat on, I prefer to avoid
> grey areas, because it avoids potential trouble later on.

Being able to read a machine description from a file at run time
sounds reasonable, as do tools to manipulate those descriptions.
I don't see why such a description file would be any different
from a firmware file or config file, especially if you were to think
of QEMU in this case more like a simulation environment
which I think is what Liviu is trying to use it as.

I agree actually including/distributing those description files is a completely
different issue if they're derived from someone elses files;
but that wouldn't stop you creating some simple examples (e.g.
the existing related machine types) from scratch.

Dave

> thanks
> -- PMM
> 
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK