On Thu, Apr 28, 2022, Maxim Levitsky wrote: > On Thu, 2022-04-28 at 15:27 +0200, Maciej S. Szmigiero wrote: > > On 28.04.2022 09:35, Maxim Levitsky wrote: > > > On Sat, 2022-04-23 at 02:14 +0000, Sean Christopherson wrote: > > > > From: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx> > > > > > > > > Don't BUG/WARN on interrupt injection due to GIF being cleared if the > > > > injected event is a soft interrupt, which are not actually IRQs and thus > > > > > > Are any injected events subject to GIF set? I think that EVENTINJ just injects > > > unconditionaly whatever hypervisor puts in it. > > > > That's right, EVENTINJ will pretty much always inject, even when the CPU > > is in a 'wrong' state (like for example, injecting a hardware interrupt > > or a NMI with GIF masked). > > > > But KVM as a L0 is not supposed to inject a hardware interrupt into guest > > with GIF unset since the guest is obviously not expecting it then. > > Hence this WARN_ON(). > > If you mean L0->L1 injection, that sure, but if L1 injects interrupt to L2, > then it should always be allowed to do so. Yes, L1 can inject whatever it wants, whenever it wants. I kept the WARN_ON() under the assumption that KVM would refuse to inject IRQs stuffed by userspace if GIF is disabled, but looking at the code again, I have no idea why I thought that. KVM_SET_VCPU_EVENTS blindly takes whatever userspace provides, I don't see anything that would prevent userspace from shoving in a hardware IRQ.
