hw/pci: delay bus_master_enable_region initialization

Skip bus_master_enable region creation on PCI device init
in order to be sure the IOMMU device (if present) would
be created in advance. Add this memory region at machine_done time.
Signed-off-by: NMarcel Apfelbaum <marcel@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pci/pci.c

@@ -78,10 +78,37 @@ static const VMStateDescription vmstate_pcibus = {
     }
 };
 
+static void pci_init_bus_master(PCIDevice *pci_dev)
+{
+    AddressSpace *dma_as = pci_device_iommu_address_space(pci_dev);
+
+    memory_region_init_alias(&pci_dev->bus_master_enable_region,
+                             OBJECT(pci_dev), "bus master",
+                             dma_as->root, 0, memory_region_size(dma_as->root));
+    memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
+    address_space_init(&pci_dev->bus_master_as,
+                       &pci_dev->bus_master_enable_region, pci_dev->name);
+}
+
+static void pcibus_machine_done(Notifier *notifier, void *data)
+{
+    PCIBus *bus = container_of(notifier, PCIBus, machine_done);
+    int i;
+
+    for (i = 0; i < ARRAY_SIZE(bus->devices); ++i) {
+        if (bus->devices[i]) {
+            pci_init_bus_master(bus->devices[i]);
+        }
+    }
+}
+
 static void pci_bus_realize(BusState *qbus, Error **errp)
 {
     PCIBus *bus = PCI_BUS(qbus);
 
+    bus->machine_done.notify = pcibus_machine_done;
+    qemu_add_machine_init_done_notifier(&bus->machine_done);
+
     vmstate_register(NULL, -1, &vmstate_pcibus, bus);
 }
 
@@ -89,6 +116,8 @@ static void pci_bus_unrealize(BusState *qbus, Error **errp)
 {
     PCIBus *bus = PCI_BUS(qbus);
 
+    qemu_remove_machine_init_done_notifier(&bus->machine_done);
+
     vmstate_unregister(NULL, &vmstate_pcibus, bus);
 }
 
@@ -920,7 +949,6 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     PCIConfigReadFunc *config_read = pc->config_read;
     PCIConfigWriteFunc *config_write = pc->config_write;
     Error *local_err = NULL;
-    AddressSpace *dma_as;
     DeviceState *dev = DEVICE(pci_dev);
 
     pci_dev->bus = bus;
@@ -961,15 +989,10 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
 
     pci_dev->devfn = devfn;
     pci_dev->requester_id_cache = pci_req_id_cache_get(pci_dev);
-    dma_as = pci_device_iommu_address_space(pci_dev);
-
-    memory_region_init_alias(&pci_dev->bus_master_enable_region,
-                             OBJECT(pci_dev), "bus master",
-                             dma_as->root, 0, memory_region_size(dma_as->root));
-    memory_region_set_enabled(&pci_dev->bus_master_enable_region, false);
-    address_space_init(&pci_dev->bus_master_as, &pci_dev->bus_master_enable_region,
-                       name);
 
+    if (qdev_hotplug) {
+        pci_init_bus_master(pci_dev);
+    }
     pstrcpy(pci_dev->name, sizeof(pci_dev->name), name);
     pci_dev->irq_state = 0;
     pci_config_alloc(pci_dev);

include/hw/pci/pci_bus.h

@@ -39,6 +39,8 @@ struct PCIBus {
        Keep a count of the number of devices with raised IRQs.  */
     int nirq;
     int *irq_count;
+
+    Notifier machine_done;
 };
 
 typedef struct PCIBridgeWindows PCIBridgeWindows;

include/sysemu/sysemu.h

@@ -75,6 +75,7 @@ void qemu_add_exit_notifier(Notifier *notify);
 void qemu_remove_exit_notifier(Notifier *notify);
 
 void qemu_add_machine_init_done_notifier(Notifier *notify);
+void qemu_remove_machine_init_done_notifier(Notifier *notify);
 
 void hmp_savevm(Monitor *mon, const QDict *qdict);
 int load_vmstate(const char *name);

vl.c

@@ -2675,6 +2675,11 @@ void qemu_add_machine_init_done_notifier(Notifier *notify)
     }
 }
 
+void qemu_remove_machine_init_done_notifier(Notifier *notify)
+{
+    notifier_remove(notify);
+}
+
 static void qemu_run_machine_init_done_notifiers(void)
 {
     notifier_list_notify(&machine_init_done_notifiers, NULL);