On Fri, Feb 12, 2021, Sean Christopherson wrote: > Paolo, this is more or less ready, but on final read-through before > sending I realized it would be a good idea to WARN during VM destruction > if cpu_dirty_logging_count is non-zero. I wanted to get you this before > the 5.12 window opens in case you want the TDP MMU fixes for 5.12. I'll > do the above change and retest next week (note, Monday is a US holiday).
Verified cpu_dirty_logging_count does indeed hit zero during VM destruction. Adding a WARN to KVM would require adding an arch hook to kvm_free_memslots(), otherwise the count will be non-zero if the VM is destroyed with dirty logging active. That doesn't seem worthwhile, so I'm not planning on pursuing a WARN for the upstream code.
