On Fri, Sep 29, 2017 at 01:30:41PM +0200, Andrew Jones wrote: > When the vPMU is in use if a VCPU's perf event overflow handler > were to fire after the VCPU started waiting, then the wake up > done by the kvm_vcpu_kick() call in the handler would do nothing, > as no "pmu overflow" state is checked in kvm_arch_vcpu_runnable(). > Fix this by checking the IRQ_PENDING VCPU request in runnable(). > Checking the request also sufficiently covers all the cases that > kvm_vgic_vcpu_pending_irq() cover, so we can just replace that. > > Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx> > --- > virt/kvm/arm/arm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c > index 5bc9b0d2fd0f..725527f491e4 100644 > --- a/virt/kvm/arm/arm.c > +++ b/virt/kvm/arm/arm.c > @@ -423,7 +423,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) > return !vcpu_should_sleep(vcpu) && > (vcpu->arch.mp_state != KVM_MP_STATE_HALTED || > (!!vcpu->arch.irq_lines || > - kvm_vgic_vcpu_pending_irq(vcpu))); > + kvm_test_request(KVM_REQ_IRQ_PENDING, vcpu))); So what if a VCPU blocks, a device raises an IRQ, the VCPU loops around, clears the KVM_REQ_IRQ_PENDING flag, enters the VM again, which does another WFI (for fun), and you end up here again with a pending IRQ but no KVM_REQ_IRQ_PENDING flag anymore. Doesn't this end up incorrectly stalling the VCPU? I don't think that a transient flag will work for a persistent binary state here. > } > > bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu) > -- > 2.13.5 > Thanks, -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
