Here is an article on lamlaw.com regarding Microsoft's potential Antitrust violations, and whether Novell is violating the GPL or not:

When Microsoft agreed with Novell to cross their promises not to sue customers, Microsoft (and Novell) have likely violated the law.

They can both stand up and make it sound like it is just another cross marketing agreement. But, that might not be the case.

As for Novell, the charge is rather simple. The agreement violates GPL 2. It certainly does so in spirit if not the letter. But, I think a case can easily be made that it also violates the letter.

The article goes on to outline manners in which Microsoft may have intentionally used this deal to sabotage the GPL, also reminding us of Microsoft's direct and indirect roles in the SCO lawsuit, which had the same intent. Antitrust concerns are also outlined as possible avenues of research.

And, in a response to Novell's assertions regarding their stance on Patents and Open Source:

It is nice to see Novell do as much as they do in regard to patents. However, working with patents does not permit nor excuse violations of the GPL. And in that regard, it is the perception of the violation that is important. It would not matter if a court of law approved the patent deal or agreed it did not violate the GPL if contributors see it another way.