On 11/24/2015 09:13 AM, Paolo Bonzini wrote:


On 24/11/2015 15:51, Estrada, Zachary J wrote:
2) Got it. Let's say I want to work with a copy of the extended page
tables instead of the original, what would be the best way to do so?

Why would you want that?  It's difficult to give an answer without
understanding what you're doing.  Notice that KVM pretty much always
leaves the X bit set (__direct_map uses ACC_ALL for the pte_access
parameter) so it's easy to go from your copy of the extended page tables
to the original.

Reply sent offlist.

I'm not sure if this is your problem, but perhaps you want to record in
the role whether the page comes from your version or the original?  The
role is like the hash key, if the role is the same you get the same PTE.

This is extremely helpful, I had not noticed this. I'm using my new root_hpa as the base_role.word - does that make sense? I just tried it and I seem to get EPT_VIOLATIONS that I was expecting, but missing.

Thanks a ton, it appears that the role was exactly the thing I was looking for!
--Zak
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