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Especially since it's not > even a robust solution for the problem. Well, corrupting CR2 is a real problem. The very best case is that fixing the pagefault at the wrong CR2 is benign, then rerun the faulting instruction having not fixed it up, and get a repeat fault which this time wins the race with the NMI and doesn't corrupt CR2, and gets fixed up properly. It's not just CR2 which is a problem; DR6 and XFD_ERR. (the other registers which have automatic side effects from exception delivery). Really, the NMI handler needs to preserve the registers it potentially clobbers, and that still requires the NMI handler doing it in assembly before entering C. ~Andrew