Re: [PATCH 4/7] KVM: nVMX: move inject_page_fault tweak to .complete_mmu_init

[Paolo Bonzini]

On 17/02/21 19:43, Maxim Levitsky wrote:
> 1. npt/ept disabled in the host. In this case we have a single shadowing
> and a nested hypervisor has to do its own shadowing on top of it.
> In this case the MMU itself has to generate page faults (they are a result
> of hardware page faults, but are completely different), and in case
> of nesting these page faults have to be sometimes injected as VM exits.
>
> [...] Also if the emulator injects the page fault, then indeed I think the
> bug will happen.

But in both cases you (ought to) get an injected exception which then 
becomes a page fault vmexit at next check_nested_events.  That's the 
part that we are all collectively missing.

Paolo