On Fri, Jul 29, 2022, Paolo Bonzini wrote: > On 7/28/22 23:20, Sean Christopherson wrote: > > > > Anyways, the bug we really care about is that by not precisely checking if a > > huge page is disallowed, KVM would refuse to create huge page after disabling > > dirty logging, which is a very noticeable performance issue for large VMs if > > a migration is canceled. That particular bug has since been unintentionally > > fixed in the TDP MMU by zapping the non-leaf SPTE, but there are other paths > > that could similarly be affected, e.g. I believe zapping leaf SPTEs in response > > to a host page migration (mmu_notifier invalidation) to create a huge page would > > yield a similar result; KVM would see the shadow-present non-leaf SPTE and assume > > a huge page is disallowed. > > Ok, thanks. So this will be 5.21 material even during the -rc phase Yes, this definitely needs more time in the queue before being sent to Linus.
