Hello All, I am preparing for a presentation for my community college, newbie to the kvm world. I am trying to understand kvm implementation. I am interested in doing a small presentation on kvm and its internals at my school. I am looking at __direct_map() . I see for_each_shadow_entry()->shadow_walk_xxx() (called in context of handle_ept_violation() ) functions using the gfn to find the iterator.sptep. It passes this iterator.sptep to the mmu_set_spte(). While I can read the code, a few questions: 1. What is the shadow_page_xxx() walk achieving ? Why is this walk necessary ? 2. Which function (mmu_sync_roots()/alloc_roots() ?) populates this table ? 3. If I put a print() around this walk, I see the same gfn's invoking the walk, finding the same sptep and invoking set_spte(). Why do we have to do this repeated operation ? (I am talking in context of handle_ept_violation() ). 4. Is the walk necessary for EPT supporting hardware as well (I am on a hardware that supports EPT, hence the question) ? 5. Is there any technical literature that talks about these data structures and help me understand the logic behind them ? If you could point me to some that will be kind of you. Thanks in advance and apologies if I am sending this to the wrong list. Any help appreciated...hopefully questions are not too vague.. Nick -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
