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

[David Hildenbrand <david@redhat.com>]

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 <david@redhat.com>
---
 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");
             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;
-- 
2.17.2