I wanted to give people a chance to patch their systems before I explain how the attack works -- and also I didn't want to upstage my own talk. You'll get the details in about 8 hours, after I finish my talk.
It's a side channel timing attack on data-dependent computation through the L1 and L2 caches. Nice work. In-the-wild exploitation is difficult, though; your timing gets screwed up if you get scheduled away from your victim, and you don't even know, because you can't tell where you were scheduled, so on any reasonably busy multiuser system it's not clear that the attack is practical.