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> You can write GPL'ed device drivers for Windows - doesn't make Windows GPL.

The public interface exposed to Windows drivers is _much_ more shallow than the public interface exposed to Linux and Solaris/Illumos modules. Not coincidentially, the Windows driver exports overlap a lot with the interface that Linux allows for usage in proprietary drivers.

Instead, KVM uses a lot of hooks into the kernel innards (into the scheduler, into the MMU, etc.) that are marked as EXPORT_SYMBOL_GPL in the Linux kernel, and the Illumos port does use some of the same hooks.

I am not a lawyer, so I don't have any clear answer. I also work for Red Hat, so even if I had one I would not want to say it (should not say it). But the licensing question is _not_ an idle question.

Also, the licensing question does not detract anything from the awesome work of these guys.

Actually, our port does not use these hooks -- there were zero mods to the illumos kernel to support KVM per se.

You do not get to choose whether it matters that the hooks (such as context ops) were preexisting. Perhaps it does, perhaps it doesn't. But it's the same trying to define what is a derived work, and neither you nor the KVM copyright holders can do that.

In the meanwhile, just thank whoever said that GPL-incompatibility was an explicit design goal for the CDDL.

The definition of a derived work is actually much more crisp than you are making it out to be -- and it is simple fact (and not opinion) that illumos is not a derived work of our KVM module. Indeed, this issue is so clear-cut and your objections so unfounded that this is beginning to sound like you are deliberately trying to place doubt over the legality of our work. So as long as we're playing Pretend Lawyer, consider your employer and look this one up: tortious interference.

> this is beginning to sound like you are deliberately trying to place doubt over the legality of our work

Oh come on. Again: if anyone has placed doubt on it, it's whoever chose CDDL because it was GPL-incompatible. All I'm saying is the question is not idle. If it was so clear-cut, it would not have popped out in 3 out of 3 places where I read about KVM/Illumos (your blog, LWN, HN).

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