On 19/12/19 20:00, Sean Christopherson wrote: >> And one last silly question, what about that line in >> kvm_arch_can_inject_async_page_present: >> >> if (!(vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED)) >> return true; >> >> That looks weird, also it shortcuts the irqs_allowed() check. > > I wondered about that code as well :-). Definitely odd, but it would > require the guest to disable async #PF after an async #PF is queued. Best > guess is the idea is that it's the guest's problem if it disables async #PF > on the fly. > When the guest disables async #PF all outstanding page faults are cancelled by kvm_clear_async_pf_completion_queue. However, in case they complete while in cancel_work_sync. you need to inject them even if interrupts are disabled. Paolo
