On Sat, 2014-12-13 at 21:43 +0100, Peter Lieven wrote:
> Am 12.12.2014 um 23:21 schrieb Alex Williamson:
> > On Fri, 2014-12-12 at 22:38 +0100, Peter Lieven wrote:
> >> Hi,
> >>
> >> we have a Cisco UCS infrastructure where we have fnic Fibre-Channel
> >> Adapters that we expose to guests. The UCS
> >> infrastruture allows to create virtual HBAs that can be exposed to a host
> >> so its possible to have quite a lot of them.
> >>
> >> We ran into a strange issue when we started having more than one vServer
> >> with a FibreChannel Adapter passed
> >> thru with vfio-pci.
> >>
> >> When a hypervisor shuts down it the kernel sees the following error:
> >>
> >> pcieport 0000:00:07.0: AER: Uncorrected (Non-Fatal) error received:
> >> id=0038
> >> pcieport 0000:00:07.0: PCIe Bus Error: severity=Uncorrected (Non-Fatal),
> >> type=Transaction Layer, id=0038(Receiver ID)
> >> pcieport 0000:00:07.0: device [8086:340e] error
> >> status/mask=00200000/00100000
> >> pcieport 0000:00:07.0: [21] Unknown Error Bit (First)
> >> pcieport 0000:00:07.0: broadcast error_detected message
> >> pcieport 0000:00:07.0: AER: Device recovery failed
> >>
> >> Bit 21 seems to be ACS Violation. And 0000:00:07.0 is the PCIE Root Port
> >> on that System.
> >>
> >> This wouldn't be a big problem, altough I would like to find out what the
> >> ACS Violation causes.
> >>
> >> The real problem is that all other vfio-pci cards on that root port get
> >> notified of this error and the connected vServers are suspended
> >> with RUN_STATE_INTERNAL_ERROR.
> >>
> >> Any ideas to work around this other than hacking qemu to not register an
> >> error handler or modifying vfio_err_notifier_handler
> >> to not suspend the vServer?
> > You could set bit 21 in the AER uncorrected error mask register to avoid
> > the root port signaling the error. Is bit 21 already clear in the
> > severity register to make this non-fatal?
> >
> >> Is it correct that all children of a root port are notified? Should qemu
> >> distinguish between fatal and non-fatal errors when
> >> suspending a vServer?
> > Yes, each child is notified. QEMU only gets an eventfd signal, which is
> > supposed to occur only for fatal errors. I don't quite understand why
> > this apparently non-fatal error is getting through. The kernel-side
> > VFIO code is where filtering of fatal vs non-fatal should occur.
>
> Had a look at vfio-pci.c from master. I can't see where there is a filtering
> of fatal vs. non-fatal
I'm under the impression that fatal vs non-fatal would be determined
somewhere in the PCI layers and the driver would only be notified for
uncorrected/fatal. Are we missing that filtering? Thanks,
Alex
> static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
> pci_channel_state_t state)
> {
> struct vfio_pci_device *vdev;
> struct vfio_device *device;
>
> device = vfio_device_get_from_dev(&pdev->dev);
> if (device == NULL)
> return PCI_ERS_RESULT_DISCONNECT;
>
> vdev = vfio_device_data(device);
> if (vdev == NULL) {
> vfio_device_put(device);
> return PCI_ERS_RESULT_DISCONNECT;
> }
>
> mutex_lock(&vdev->igate);
>
> if (vdev->err_trigger)
> eventfd_signal(vdev->err_trigger, 1);
>
> mutex_unlock(&vdev->igate);
>
> vfio_device_put(device);
>
> return PCI_ERS_RESULT_CAN_RECOVER;
> }
>
> static struct pci_error_handlers vfio_err_handlers = {
> .error_detected = vfio_pci_aer_err_detected,
> };
>
> static struct pci_driver vfio_pci_driver = {
> .name = "vfio-pci",
> .id_table = NULL, /* only dynamic ids */
> .probe = vfio_pci_probe,
> .remove = vfio_pci_remove,
> .err_handler = &vfio_err_handlers,
> };
>
> Peter
>
>
