On 13/09/19 21:01, Suthikulpanit, Suravee wrote: > /* > + * In case APICv accelerate EOI write and do not trap, > + * in-kernel IOAPIC will not be able to receive the EOI. > + * In this case, we do lazy update of the pending EOI when > + * trying to set IOAPIC irq. > + */ > + if (kvm_apicv_eoi_accelerate(ioapic->kvm, edge)) > + ioapic_lazy_update_eoi(ioapic, irq); > +
This is okay for the RTC, and in fact I suggest that you make it work like this even for Intel. This will get rid of kvm_apicv_eoi_accelerate and be nicer overall. However, it cannot work for the in-kernel PIT, because it is currently checking ps->irq_ack before kvm_set_irq. Unfortunately, the in-kernel PIT is relying on the ack notifier to timely queue the pt->worker work item and reinject the missed tick. Thus, you cannot enable APICv if ps->reinject is true. Perhaps you can make kvm->arch.apicv_state a disabled counter? Then Hyper-V can increment it when enabled, PIT can increment it when ps->reinject becomes true and decrement it when it becomes false; finally, svm.c can increment it when an SVM guest is launched and increment/decrement it around ExtINT handling? (This conflicts with some of the suggestions I made earlier, which implied the existence of apicv_state, but everything should if anything become easier). Paolo
