Re: [PATCH] paravirt.h

Zachary Amsden
2006-08-22T19:27:09Z

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