pci: Fold host_buses list into PCIHostState functionality

The host_buses list is an odd structure - a list of pointers to PCI root
buses existing in parallel to the normal qdev tree structure.  This patch
removes it, instead putting the link pointers into the PCIHostState
structure, which have a 1:1 relationship to PCIHostBus structures anyway.
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/pci/pci.c

@@ -90,11 +90,7 @@ static void pci_del_option_rom(PCIDevice *pdev);
 static uint16_t pci_default_sub_vendor_id = PCI_SUBVENDOR_ID_REDHAT_QUMRANET;
 static uint16_t pci_default_sub_device_id = PCI_SUBDEVICE_ID_QEMU;
 
-struct PCIHostBus {
-    struct PCIBus *bus;
-    QLIST_ENTRY(PCIHostBus) next;
-};
-static QLIST_HEAD(, PCIHostBus) host_buses;
+static QLIST_HEAD(, PCIHostState) pci_host_bridges;
 
 static const VMStateDescription vmstate_pcibus = {
     .name = "PCIBUS",
@@ -237,20 +233,19 @@ static int pcibus_reset(BusState *qbus)
     return 1;
 }
 
-static void pci_host_bus_register(PCIBus *bus)
+static void pci_host_bus_register(PCIBus *bus, DeviceState *parent)
 {
-    struct PCIHostBus *host;
-    host = g_malloc0(sizeof(*host));
-    host->bus = bus;
-    QLIST_INSERT_HEAD(&host_buses, host, next);
+    PCIHostState *host_bridge = PCI_HOST_BRIDGE(parent);
+
+    QLIST_INSERT_HEAD(&pci_host_bridges, host_bridge, next);
 }
 
 PCIBus *pci_find_primary_bus(void)
 {
     PCIBus *primary_bus = NULL;
-    struct PCIHostBus *host;
+    PCIHostState *host;
 
-    QLIST_FOREACH(host, &host_buses, next) {
+    QLIST_FOREACH(host, &pci_host_bridges, next) {
         if (primary_bus) {
             /* We have multiple root buses, refuse to select a primary */
             return NULL;
@@ -302,7 +297,7 @@ static void pci_bus_init(PCIBus *bus, DeviceState *parent,
     /* host bridge */
     QLIST_INIT(&bus->child);
 
-    pci_host_bus_register(bus);
+    pci_host_bus_register(bus, parent);
 
     vmstate_register(NULL, -1, &vmstate_pcibus, bus);
 }
@@ -1533,11 +1528,11 @@ static PciInfo *qmp_query_pci_bus(PCIBus *bus, int bus_num)
 PciInfoList *qmp_query_pci(Error **errp)
 {
     PciInfoList *info, *head = NULL, *cur_item = NULL;
-    struct PCIHostBus *host;
+    PCIHostState *host_bridge;
 
-    QLIST_FOREACH(host, &host_buses, next) {
+    QLIST_FOREACH(host_bridge, &pci_host_bridges, next) {
         info = g_malloc0(sizeof(*info));
-        info->value = qmp_query_pci_bus(host->bus, 0);
+        info->value = qmp_query_pci_bus(host_bridge->bus, 0);
 
         /* XXX: waiting for the qapi to support GSList */
         if (!cur_item) {
@@ -2201,11 +2196,11 @@ static int pci_qdev_find_recursive(PCIBus *bus,
 
 int pci_qdev_find_device(const char *id, PCIDevice **pdev)
 {
-    struct PCIHostBus *host;
+    PCIHostState *host_bridge;
     int rc = -ENODEV;
 
-    QLIST_FOREACH(host, &host_buses, next) {
-        int tmp = pci_qdev_find_recursive(host->bus, id, pdev);
+    QLIST_FOREACH(host_bridge, &pci_host_bridges, next) {
+        int tmp = pci_qdev_find_recursive(host_bridge->bus, id, pdev);
         if (!tmp) {
             rc = 0;
             break;

include/hw/pci/pci_host.h

@@ -46,6 +46,8 @@ struct PCIHostState {
     MemoryRegion mmcfg;
     uint32_t config_reg;
     PCIBus *bus;
+
+    QLIST_ENTRY(PCIHostState) next;
 };
 
 typedef struct PCIHostBridgeClass {