On Mon, Sep 3, 2018 at 5:20 AM Liran Alon <liran.alon@xxxxxxxxxx> wrote: > > Consider the case L1 had a IRQ/NMI event until it executed > VMLAUNCH/VMRESUME which wasn't delivered because it was disallowed > (e.g. interrupts disabled). When L1 executes VMLAUNCH/VMRESUME, > L0 needs to evaluate if this pending event should cause an exit from > L2 to L1 or delivered directly to L2 (e.g. In case L1 don't intercept > EXTERNAL_INTERRUPT). > > Usually this would be handled by L0 requesting a IRQ/NMI window > by setting VMCS accordingly. However, this setting was done on > VMCS01 and now VMCS02 is active instead. Thus, when L1 executes > VMLAUNCH/VMRESUME we force L0 to perform pending event evaluation by > requesting a KVM_REQ_EVENT. > > Note that above scenario exists when L1 KVM is about to enter L2 but > requests an "immediate-exit". As in this case, L1 will > disable-interrupts and then send a self-IPI before entering L2. What about the case where the pending IRQ is sitting in L1's posted-interrupt descriptor, and L2 takes an external-interrupt VM-exit for L1's posted-interrupt notification vector (whether or not external-interrupt exiting is enabled in vmcs12)?
