KVM hook for code integrity checking

[Suen Chun Hui <chunhui.suen@tum.de>]

Dear KVM developers,

I'm currently working on an open source security patch to use KVM to
implement code verification on a guest VM in runtime. Thus, it would be
very helpful if someone can point to me the right function or place to
look at for adding 2 hooks into the KVM paging code to:

1. Detect a new guest page (which I assume will imply a new pte and
imply a new spte).
Currently, I'm considering putting a hook in the function
mmu_set_spte(), but may there is a better place.
This hook will be used as the main entry point into the code
verification function

2. Detect a write fault to a read-only spte (eg. for the case of
updating the dirty bit back to the guest pte)
Unfortunately, I'm unable to find an appropriate place where this
actually takes place after reading the code many times.
This hook will be used to prevent a secondary "peek" page from modifying
an existing verified code page.

I will gladly contribute my work(my phd thesis) to the list once it is
workable, if anyone find it useful.
Thank you in advance.

Regards,
Chun Hui