Shadow MMU state preserved across kvm_mmu_zap_all?

[Marek Olszewski <mareko@csail.mit.edu>]

Hello,

I'm trying to track down a bug I'm observing in a branched version of 
kvm I'm using for research.  I'm hoping someone might be able to point 
me int to the right direction as I haven't had any luck with it on my 
own.  Here are the details:

I have made some changes to kvm that enable guest user applications to 
use duplicate shadow pages to do interesting things (essentially I 
duplicate the shadow page table tree for a process multiple times, once 
for each thread).  During my tests, my guest application enables this 
new feature, completes correctly, and then disables it.  Unfortunately, 
after the test application completes, random programs begin segfaulting 
for unknown reasons.  This is despite the fact that my changes to KVM no 
longer get executed (verified with a kgdb).  At first I thought that I 
corrupted the shadow pages tables somehow, however, calling 
kvm_mmu_zap_all does not solve the problem.  Thus, I figured I corrupted 
the guest OS somehow, however, the problem persists even if I reboot the 
guest OS.  

So my question is this: Are there any other data structures that survive 
both a call to kvm_mmu_zap and a guest reboot?

Thanks!

Marek