hw/pci: fix error flow in pci multifunction init

Scenario:
  - There is a non multifunction pci device A on 00:0X.0.
  - Hot-plug another multifunction pci device B at 00:0X.1.
  - The operation will fail of course.
  - Try to hot-plug the B device 2-3 more times, qemu will crash.

Reason: The error flow leaves the B's address space into global address spaces
list, but the device object is freed. Fixed that.
Signed-off-by: NMarcel Apfelbaum <marcel.a@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pci/pci.c

@@ -793,6 +793,15 @@ static void pci_config_free(PCIDevice *pci_dev)
     g_free(pci_dev->used);
 }
 
+static void do_pci_unregister_device(PCIDevice *pci_dev)
+{
+    pci_dev->bus->devices[pci_dev->devfn] = NULL;
+    pci_config_free(pci_dev);
+
+    address_space_destroy(&pci_dev->bus_master_as);
+    memory_region_destroy(&pci_dev->bus_master_enable_region);
+}
+
 /* -1 for devfn means auto assign */
 static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
                                          const char *name, int devfn)
@@ -858,7 +867,7 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
         pci_init_mask_bridge(pci_dev);
     }
     if (pci_init_multifunction(bus, pci_dev)) {
-        pci_config_free(pci_dev);
+        do_pci_unregister_device(pci_dev);
         return NULL;
     }
 
@@ -873,15 +882,6 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     return pci_dev;
 }
 
-static void do_pci_unregister_device(PCIDevice *pci_dev)
-{
-    pci_dev->bus->devices[pci_dev->devfn] = NULL;
-    pci_config_free(pci_dev);
-
-    address_space_destroy(&pci_dev->bus_master_as);
-    memory_region_destroy(&pci_dev->bus_master_enable_region);
-}
-
 static void pci_unregister_io_regions(PCIDevice *pci_dev)
 {
     PCIIORegion *r;