Hello! > As for v4.1 not having that problem, the pl011 driver has gone though a > lot if rework lately, and I wouldn't be surprised if it now exhibited a > different behaviour thanks to the broken userspace behaviour. Sorry, you misunderstood me. Or i wrote badly. I meant that _KVM_ did not have this particular problem in kernel v4.0, because: http://lxr.free-electrons.com/source/virt/kvm/arm/vgic.c?v=4.0#L998 you see, LR_STATE_PENDING is assigned unconditionally. Is this code correct? I believe yes. Compare with: http://lxr.free-electrons.com/source/virt/kvm/arm/vgic.c#L1104 Now it is possible to have neither PENDING nor ACTIVE irq. Does it even make sense? So what is wrong with the modification as follows? --- cut --- if (vgic_irq_is_active(vcpu, irq)) { vlr.state |= LR_STATE_ACTIVE; kvm_debug("Set active, clear distributor: 0x%x\n", vlr.state); vgic_irq_clear_active(vcpu, irq); vgic_update_state(vcpu->kvm); } else { vlr.state |= LR_STATE_PENDING; kvm_debug("Set pending: 0x%x\n", vlr.state); } --- cut --- Alex, are you reading us? Can you explain, why you introduced that extra check? > And what you're suggesting is to actually introduce a bug. Why would that be a bug, if it was not a bug in kernel 4.0? Kind regards, Pavel Fedin Expert Engineer Samsung Electronics Research center Russia _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
