On Fri, Feb 07, 2025, Yan Zhao wrote:
> Merge the prefetch check into the is_access_allowed() check to determine a
> spurious fault.
>
> In the TDP MMU, a spurious prefetch fault should also pass the
> is_access_allowed() check.
How so?
1. vCPU takes a write-fault on a swapped out page and queues an async #PF
2. A different task installs a writable SPTE
3. A third task write-protects the SPTE for dirty logging
4. Async #PF handler faults in the SPTE, encounters a read-only SPTE for its
write fault.
KVM shouldn't mark the gfn as dirty in this case.
