On Wed, Jan 30, 2013 at 09:03:11PM -0200, Marcelo Tosatti wrote: > Posted interrupt patch: > 2) Must move IN_GUEST_MODE assignment after local_irq_disable, in > vcpu_enter_guest function. Otherwise: > > cpu0 vcpu1<->cpu1 > > vcpu->mode = IN_GUEST_MODE > > if IN_GUEST_MODE == true > send IPI > local_irq_disable > > PIR not transferred to VIRR, misses interrupt. > cpu0 will set KVM_REQ_EVENT, so vmentry will be aborted after local_irq_disable() by ->requests check. > 3) Must check outstanding PIR notification bit unconditionally on > every VM-entry, because: > > 1. local_irq_disable > 2. vcpu->mode = IN_GUEST_MODE > 3. vmenter > 4. vmexit > 5. vcpu->mode = OUTSIDE_GUEST_MODE > > If PIR-IPI-interrupt is sent between an event which triggers VM-exit > (for example, an external interrupt due to a device), and step 5 > (assignment of vcpu->mode), the PIR->VIRR transfer before vmentry must > be made. Not sure I understand, but I think KVM_REQ_EVENT will cover that too. > > 4) Today, an interrupt notification is cached on IRR until its delivered - further > interrupt injection is not generating further interrupt notification > bits. With PIR, behaviour changes: Its possible to have one bit in PIR and another > on IRR APIC page (if timing is right). Is this harmless? Why? > > -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
