Re: [qemu-s390x] [PATCH v1 3/4] s390x/zpci: move some hotplug checks to the pre_plug handler

[David Hildenbrand]

On 05.11.18 12:03, David Hildenbrand wrote:
> Let's move most of the checks to the new pre_plug handler. As a PCI
> bridge is just a PCI device, we can simplify the code.
> 
> Notes: We cannot yet move the MSIX check or device ID creation +
> zPCI device creation to the pre_plug handler as both parts are not
> fixed before actual device realization (and therefore after pre_plug and
> before plug). Once that part is factored out, we can move these parts to
> the pre_plug handler, too and therefore remove all possible errors from
> the plug handler.
> 
> Signed-off-by: David Hildenbrand <address@hidden>
> ---
>  hw/s390x/s390-pci-bus.c | 43 +++++++++++++++++++++++++----------------
>  1 file changed, 26 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
> index 68660eac74..1849f9d334 100644
> --- a/hw/s390x/s390-pci-bus.c
> +++ b/hw/s390x/s390-pci-bus.c
> @@ -806,11 +806,31 @@ static bool s390_pci_alloc_idx(S390pciState *s, 
> S390PCIBusDevice *pbdev)
>      }
>  
>      pbdev->idx = idx;
> -    s->next_idx = (idx + 1) & FH_MASK_INDEX;
> -
>      return true;
>  }
>  
> +static void s390_pcihost_pre_plug(HotplugHandler *hotplug_dev, DeviceState 
> *dev,
> +                                   Error **errp)
> +{
> +    S390pciState *s = S390_PCI_HOST_BRIDGE(hotplug_dev);
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
> +        PCIDevice *pdev = PCI_DEVICE(dev);
> +
> +        if (pdev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
> +            error_setg(errp, "multifunction not supported in s390");
> +            return;
> +        }
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_S390_PCI_DEVICE)) {
> +        S390PCIBusDevice *pbdev = S390_PCI_DEVICE(dev);
> +
> +        if (!s390_pci_alloc_idx(s, pbdev)) {
> +            error_setg(errp, "no slot for plugging zpci device");
> +            return;
> +        }
> +    }
> +}
> +
>  static void s390_pcihost_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
>                                Error **errp)
>  {
> @@ -823,11 +843,6 @@ static void s390_pcihost_plug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>          PCIBridge *pb = PCI_BRIDGE(dev);
>          PCIDevice *pdev = PCI_DEVICE(dev);
>  
> -        if (pdev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
> -            error_setg(errp, "multifunction not supported in s390");
> -            return;
> -        }
> -
>          pci_bridge_map_irq(pb, dev->id, s390_pci_map_irq);
>          pci_setup_iommu(&pb->sec_bus, s390_pci_dma_iommu, s);
>  
> @@ -847,11 +862,6 @@ static void s390_pcihost_plug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
>          pdev = PCI_DEVICE(dev);
>  
> -        if (pdev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
> -            error_setg(errp, "multifunction not supported in s390");
> -            return;
> -        }
> -
>          if (!dev->id) {
>              /* In the case the PCI device does not define an id */
>              /* we generate one based on the PCI address         */
> @@ -883,7 +893,7 @@ static void s390_pcihost_plug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>  
>          if (s390_pci_msix_init(pbdev)) {
>              error_setg(errp, "MSI-X support is mandatory "
> -                       "in the S390 architecture");
> +                             "in the S390 architecture");

I will drop this unrelated change.

>              return;
>          }
>  
> @@ -894,10 +904,8 @@ static void s390_pcihost_plug(HotplugHandler 
> *hotplug_dev, DeviceState *dev,
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_S390_PCI_DEVICE)) {
>          pbdev = S390_PCI_DEVICE(dev);
>  
> -        if (!s390_pci_alloc_idx(s, pbdev)) {
> -            error_setg(errp, "no slot for plugging zpci device");
> -            return;
> -        }
> +        /* the allocated idx is actually getting used */
> +        s->next_idx = (pbdev->idx + 1) & FH_MASK_INDEX;
>          pbdev->fh = pbdev->idx;
>          QTAILQ_INSERT_TAIL(&s->zpci_devs, pbdev, link);
>          g_hash_table_insert(s->zpci_table, &pbdev->idx, pbdev);
> @@ -1030,6 +1038,7 @@ static void s390_pcihost_class_init(ObjectClass *klass, 
> void *data)
>  
>      dc->reset = s390_pcihost_reset;
>      dc->realize = s390_pcihost_realize;
> +    hc->pre_plug = s390_pcihost_pre_plug;
>      hc->plug = s390_pcihost_plug;
>      hc->unplug = s390_pcihost_unplug;
>      msi_nonbroken = true;
> 


-- 

Thanks,

David / dhildenb