Re: [Qemu-devel] [patch v3 6/9] vfio: add check aer functionality for hotplug device

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 15 Mar 2016 09:35:46 +0800
Cao jin <caoj.fnst@cn.fujitsu.com> wrote:

> From: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> 
> because we make the vfio functions are combined
> in the same way as on the host for aer, so we can
> do the aer check when the function 0 was hotplugged.
> 
> Signed-off-by: Chen Fan <chen.fan.fnst@cn.fujitsu.com>
> ---
>  hw/vfio/pci.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 9670271..223c0ee 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -2029,6 +2029,40 @@ out:
>      return;
>  }
>  
> +static void vfio_bus_check_aer_functions(PCIDevice *pdev, Error **errp)
> +{
> +    PCIBus *bus = pdev->bus;
> +    VFIOPCIDevice *vdev;
> +    PCIDevice *dev;
> +    Error *local_err = NULL;
> +    int devfn;
> +
> +    for (devfn = 0; devfn < ARRAY_SIZE(bus->devices); devfn++) {
> +        dev = bus->devices[devfn];
> +        if (!dev) {
> +            continue;
> +        }
> +
> +        if (pci_get_function_0(dev) != pdev) {
> +            return;
> +        }

It seems like there are much easier ways to walk all functions on a
slot, rather than all devices on the bus, and not access PCIBus private
data:

for (fn = 0; fn < 8; fn++) {
    dev = pci_find_device(pdev->bus, pci_bus_num(pdev->bus),
                          PCI_DEVFN(PCI_SLOT(pdev->devfn), fn));
    if (!dev) {
        continue;
    }

    ...


> +
> +        if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
> +            continue;
> +        }
> +        vdev = DO_UPCAST(VFIOPCIDevice, pdev, dev);
> +        if (vdev->features & VFIO_FEATURE_ENABLE_AER) {
> +            vfio_check_hot_bus_reset(vdev, &local_err);
> +            if (local_err) {
> +                error_propagate(errp, local_err);
> +                return;
> +            }
> +        }
> +    }
> +
> +    return;
> +}
> +
>  static void vfio_aer_check_host_bus_reset(Error **errp)
>  {
>      VFIOGroup *group;
> @@ -2962,6 +2996,22 @@ static int vfio_initfn(PCIDevice *pdev)
>          }
>      }
>  
> +    /*
> +     *  If this function is func 0, indicate the closure of the slot.
> +     *  we get the chance to check aer-enabled devices whether support
> +     *  hot bus reset.
> +     */
> +    if (DEVICE(pdev)->hotplugged &&
> +        pdev == pci_get_function_0(pdev)) {
> +        Error *local_err = NULL;
> +
> +        vfio_bus_check_aer_functions(pdev, &local_err);
> +        if (local_err) {
> +            error_report_err(local_err);
> +            goto out_teardown;
> +        }
> +    }
> +
>      vfio_register_err_notifier(vdev);
>      vfio_register_req_notifier(vdev);
>      vfio_setup_resetfn_quirk(vdev);