Zachary Amsden wrote:

 > I've already implemented the locking and repatching bits for VMI.


Incorrectly, I might add.  The problem case for syscall patching is what 
do you do if there are in-service system calls?  The comparable problem 
here is what if you interrupt code running in the old paravirt-ops, or 
worse, a section of code that you repatch when you do the switch?

That is a really nasty problem.  You need a synchronization primitive 
which guarantees a flat stack, so you can't do it in the interrupt 
handler as I have tried to do.  I'll bang my head on it awhile.  In the 
meantime, were there ever any solutions to the syscall patching problem 
that might lend me a clue as to what to do (or not to do, or impossible?).

Thanks,

Zach