Re: [PATCH] paravirt.h

From: Zachary Amsden
Date: Tue Aug 22 2006 - 15:24:32 EST


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
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