Nested EPT page fault

Nested EPT page fault

[Hu Yaohui]

Hi,
I have one question related to nested EPT page fault.
At the very start, L0 hypervisor launches L2 with an empty EPT0->2
table, building the table on-the-fly.
when one L2 physical page is accessed, ept_page_fault(paging_tmpl.h)
will be called to handle this fault in L0. which will first call
ept_walk_addr to get guest ept entry from EPT1->2. If there is no such
entry, a guest page fault will be injected into L1 to handle this
fault.
When the next time, the same L2 physical page is accessed,
ept_page_fault will be triggered again in L0, which will also call
ept_walk_addr and get the previously filled ept entry in EPT1->2, then
try_async_pf will be called to translate the L1 physical page to L0
physical page. At the very last, an entry will be created in the
EPT0->2 to solve the page fault.
Please correct me if I am wrong.

My question is when the EPT0->1 will be accessed during the EPT0->2
entry created, since according to the turtle's paper, both EPT0->1 and
EPT->12 will be accessed to populate an entry in EPT0->2.

Thanks for your time!

Best Wishes,
Yaohui