On 03/11/2016 21:16, Radim Krčmář wrote: > > + if (!pi_test_on(&vmx->pi_desc)) > > We don't call vmx_hwapic_irr_update() when returning early.
This might be a good start, but it's on purpose: IRR is not changing and the invariant _should_ be that RVI=highest-bit(IRR): - IRR cleared by processor: see SDM 29.2.2 Virtual-interrupt delivery - IRR set by processor: see SDM 29.6 Posted-interrupt processing - IRR set by KVM: ON=1 so it doesn't exit here - IRR cleared by KVM: might indeed be buggy here, but the next patch does add a + kvm_x86_ops->hwapic_irr_update(vcpu, + apic_find_highest_irr(apic)); to apic_clear_irr, which doesn't fix the bug (and doesn't fix it also if backported here). So we're missing a place where IRR has changed but RVI is not being updated. It should be related to vmx_check_nested_events and kvm_cpu_has_interrupt as you said, but I cannot really see it. Paolo >> > + return; >> > + >> > + pi_clear_on(&vmx->pi_desc); >> > + max_irr = kvm_apic_update_irr(vcpu, vmx->pi_desc.pir); >> > + vmx_hwapic_irr_update(vcpu, max_irr); >> > +}
