Hi Alex, On 04/26/2016 10:08 PM, Alex Williamson wrote: > On Fri, 18 Sep 2015 22:29:50 +0800 > Feng Wu <feng...@intel.com> wrote: > > @@ -360,6 +361,14 @@ static int vfio_msi_set_vector_signal(struct > vfio_pci_device *vdev, >> return ret; >> } >> >> + vdev->ctx[vector].producer.token = trigger; >> + vdev->ctx[vector].producer.irq = irq; >> + ret = irq_bypass_register_producer(&vdev->ctx[vector].producer); >> + if (unlikely(ret)) >> + dev_info(&pdev->dev, >> + "irq bypass producer (token %p) registeration fails: %d\n", >> + vdev->ctx[vector].producer.token, ret); >> + >> vdev->ctx[vector].trigger = trigger; >> >> return 0; > > Digging back into the IRQ producer/consumer thing, I'm not sure how we > should be handling a failure here, but it turns out that what we have > is pretty sub-optimal. Any sort of testing on AMD hits this dev_info > because kvm_arch_irq_bypass_add_producer() returns -EINVAL without > kvm_x86_ops->update_pi_irte which is only implemented for vmx. Clearly > we don't want to spew confusing error messages for a feature that does > not exist. > > The easiest option is to simply make this error silent, but should > registering a producer/consumer really fail due to a mismatch on the > other end or should the __connect sequence fail silently, which both > ends would know about (if they care) due to the add/del handshake > between them? Perhaps for now we simply need a stable suitable fix to > silence the dev_info above, but longer term, registration shouldn't > fail for mismatches like this. Thoughts? Thanks,
Regarding the ARM IRQ forwarding use case, I think it is OK to fail silently. We would fall back to the irqfd standard mechanism. Anyway this series still is waiting for ARM new-vgic dependency to be resolved, as discussed with Christoffer and Marc. Best Regards Eric > > Alex >
