On Thu, Jun 3, 2021 at 5:33 PM Wanpeng Li <kernellwp@xxxxxxxxx> wrote: > > On Fri, 4 Jun 2021 at 07:02, David Matlack <dmatlack@xxxxxxxxxx> wrote: > > > > On Thu, Jun 3, 2021 at 2:04 AM Wanpeng Li <kernellwp@xxxxxxxxx> wrote: > > > > > > From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > > > > > > According to the SDM 10.5.4.1: > > > > > > A write of 0 to the initial-count register effectively stops the local > > > APIC timer, in both one-shot and periodic mode. > > > > If KVM is not correctly emulating this behavior then could you also > > add a kvm-unit-test to test for the correct behavior? > > A simple test here, the test will hang after the patch since it will > not receive the spurious interrupt any more. Thanks. Can you send this as a [PATCH]? I think it would be worthwhile so have a regression test for this bug. > > diff --git a/x86/apic.c b/x86/apic.c > index a7681fe..947d018 100644 > --- a/x86/apic.c > +++ b/x86/apic.c > @@ -488,6 +488,14 @@ static void test_apic_timer_one_shot(void) > */ > report((lvtt_counter == 1) && (tsc2 - tsc1 >= interval), > "APIC LVT timer one shot"); > + > + lvtt_counter = 0; > + apic_write(APIC_TMICT, interval); > + apic_write(APIC_TMICT, 0); > + while (!lvtt_counter); > + > + report((lvtt_counter == 1), > + "APIC LVT timer one shot spurious interrupt"); > }
