Re: [Qemu-devel] QEMU License and proprietary hardware

[Paul Brook <paul@codesourcery.com>]

On Thursday 21 June 2007, Armbrost Failsafe wrote:
> We are looking into using QEMU as the base for a model of a custom system
> featuring some custom ASICs. But licensing issues are halting the process
> right now. Does anyone know what happens license-wise if we create a model
> of proprietary hardware using QEMU? Is that model automatically covered by
> the GPL and thus we have to give to anyone who asks about it? It is clear
> that if we keep it internal, it is OK. But anyone outside of our
> organization is to use it, shouldn't they automatically be entitled to
> receive the entire source of QEMU, including our models of proprietary
> devices? 

Please read


As someone who has written significant portions of qemu code, and would be in 
a position to enforce the licence requirements, teh short answer is:

- If you never distribute (give away or sell) your model to anyone, you can do 
what you like.
- If you distribute binaries containing GPL code you must also provide source 
for the whole application, including your model.
- If you remove all the GPL code from qemu (leaving just the LGPL/BSD parts) 
and distribute the remainder then you must provide source for all the LGPL 
parts you have touched, and some mechanism for relinking modified versions of 
qemu against your proprietary components.

If you disagree with my summarry then you need to contact the Free Software 
Foundation and/or seek professional legal advice. As others have mentioned 
(with varying degrees of accuracy) there are grey areas and different legal 
interpretations of the terms of the GPL. This in not the correct place for 
such discussions.

See also http://www.gnu.org/licenses/licenses.html#GPL

> Even if these are developed from scratch without using any
> existing source code for devices?

IMHO this question doesn't make any sense. Either you're using (linking with) 
GPL code, or you aren't.

Paul