pci: Eliminate redundant PCIDevice::bus pointer

The bus pointer in PCIDevice is basically redundant with QOM information.
It's always initialized to the qdev_get_parent_bus(), the only difference
is the type.

Therefore this patch eliminates the field, instead creating a pci_get_bus()
helper to do the type mangling to derive it conveniently from the QOM
Device object underneath.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

4 files changed, 47 insertions, 42 deletions

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 232e7da..567be1b 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -222,7 +222,7 @@ static void pci_change_irq_level(PCIDevice *pci_dev, int irq_num, int change)
 {
     PCIBus *bus;
     for (;;) {
-        bus = pci_dev->bus;
+        bus = pci_get_bus(pci_dev);
         irq_num = bus->map_irq(pci_dev, irq_num);
         if (bus->set_irq)
             break;
@@ -349,13 +349,13 @@ PCIBus *pci_find_primary_bus(void)
 
 PCIBus *pci_device_root_bus(const PCIDevice *d)
 {
-    PCIBus *bus = d->bus;
+    PCIBus *bus = pci_get_bus(d);
 
     while (!pci_bus_is_root(bus)) {
         d = bus->parent_dev;
         assert(d != NULL);
 
-        bus = d->bus;
+        bus = pci_get_bus(d);
     }
 
     return bus;
@@ -882,7 +882,7 @@ static void pci_config_free(PCIDevice *pci_dev)
 
 static void do_pci_unregister_device(PCIDevice *pci_dev)
 {
-    pci_dev->bus->devices[pci_dev->devfn] = NULL;
+    pci_get_bus(pci_dev)->devices[pci_dev->devfn] = NULL;
     pci_config_free(pci_dev);
 
     if (memory_region_is_mapped(&pci_dev->bus_master_enable_region)) {
@@ -903,7 +903,7 @@ static uint16_t pci_req_id_cache_extract(PCIReqIDCache *cache)
         result = pci_get_bdf(cache->dev);
         break;
     case PCI_REQ_ID_SECONDARY_BUS:
-        bus_n = pci_bus_num(cache->dev->bus);
+        bus_n = pci_dev_bus_num(cache->dev);
         result = PCI_BUILD_BDF(bus_n, 0);
         break;
     default:
@@ -933,9 +933,9 @@ static PCIReqIDCache pci_req_id_cache_get(PCIDevice *dev)
         .type = PCI_REQ_ID_BDF,
     };
 
-    while (!pci_bus_is_root(dev->bus)) {
+    while (!pci_bus_is_root(pci_get_bus(dev))) {
         /* We are under PCI/PCIe bridges */
-        parent = dev->bus->parent_dev;
+        parent = pci_get_bus(dev)->parent_dev;
         if (pci_is_express(parent)) {
             if (pcie_cap_get_type(parent) == PCI_EXP_TYPE_PCI_BRIDGE) {
                 /* When we pass through PCIe-to-PCI/PCIX bridges, we
@@ -978,7 +978,7 @@ static bool pci_bus_devfn_reserved(PCIBus *bus, int devfn)
 }
 
 /* -1 for devfn means auto assign */
-static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
+static PCIDevice *do_pci_register_device(PCIDevice *pci_dev,
                                          const char *name, int devfn,
                                          Error **errp)
 {
@@ -987,8 +987,8 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     PCIConfigWriteFunc *config_write = pc->config_write;
     Error *local_err = NULL;
     DeviceState *dev = DEVICE(pci_dev);
+    PCIBus *bus = pci_get_bus(pci_dev);
 
-    pci_dev->bus = bus;
     /* Only pci bridges can be attached to extra PCI root buses */
     if (pci_bus_is_root(bus) && bus->parent_dev && !pc->is_bridge) {
         error_setg(errp,
@@ -1142,8 +1142,8 @@ void pci_register_bar(PCIDevice *pci_dev, int region_num,
     r->type = type;
     r->memory = memory;
     r->address_space = type & PCI_BASE_ADDRESS_SPACE_IO
-                        ? pci_dev->bus->address_space_io
-                        : pci_dev->bus->address_space_mem;
+                        ? pci_get_bus(pci_dev)->address_space_io
+                        : pci_get_bus(pci_dev)->address_space_mem;
 
     wmask = ~(size - 1);
     if (region_num == PCI_ROM_SLOT) {
@@ -1185,21 +1185,23 @@ static void pci_update_vga(PCIDevice *pci_dev)
 void pci_register_vga(PCIDevice *pci_dev, MemoryRegion *mem,
                       MemoryRegion *io_lo, MemoryRegion *io_hi)
 {
+    PCIBus *bus = pci_get_bus(pci_dev);
+
     assert(!pci_dev->has_vga);
 
     assert(memory_region_size(mem) == QEMU_PCI_VGA_MEM_SIZE);
     pci_dev->vga_regions[QEMU_PCI_VGA_MEM] = mem;
-    memory_region_add_subregion_overlap(pci_dev->bus->address_space_mem,
+    memory_region_add_subregion_overlap(bus->address_space_mem,
                                         QEMU_PCI_VGA_MEM_BASE, mem, 1);
 
     assert(memory_region_size(io_lo) == QEMU_PCI_VGA_IO_LO_SIZE);
     pci_dev->vga_regions[QEMU_PCI_VGA_IO_LO] = io_lo;
-    memory_region_add_subregion_overlap(pci_dev->bus->address_space_io,
+    memory_region_add_subregion_overlap(bus->address_space_io,
                                         QEMU_PCI_VGA_IO_LO_BASE, io_lo, 1);
 
     assert(memory_region_size(io_hi) == QEMU_PCI_VGA_IO_HI_SIZE);
     pci_dev->vga_regions[QEMU_PCI_VGA_IO_HI] = io_hi;
-    memory_region_add_subregion_overlap(pci_dev->bus->address_space_io,
+    memory_region_add_subregion_overlap(bus->address_space_io,
                                         QEMU_PCI_VGA_IO_HI_BASE, io_hi, 1);
     pci_dev->has_vga = true;
 
@@ -1208,15 +1210,17 @@ void pci_register_vga(PCIDevice *pci_dev, MemoryRegion *mem,
 
 void pci_unregister_vga(PCIDevice *pci_dev)
 {
+    PCIBus *bus = pci_get_bus(pci_dev);
+
     if (!pci_dev->has_vga) {
         return;
     }
 
-    memory_region_del_subregion(pci_dev->bus->address_space_mem,
+    memory_region_del_subregion(bus->address_space_mem,
                                 pci_dev->vga_regions[QEMU_PCI_VGA_MEM]);
-    memory_region_del_subregion(pci_dev->bus->address_space_io,
+    memory_region_del_subregion(bus->address_space_io,
                                 pci_dev->vga_regions[QEMU_PCI_VGA_IO_LO]);
-    memory_region_del_subregion(pci_dev->bus->address_space_io,
+    memory_region_del_subregion(bus->address_space_io,
                                 pci_dev->vga_regions[QEMU_PCI_VGA_IO_HI]);
     pci_dev->has_vga = false;
 }
@@ -1319,7 +1323,7 @@ static void pci_update_mappings(PCIDevice *d)
 
         /* now do the real mapping */
         if (r->addr != PCI_BAR_UNMAPPED) {
-            trace_pci_update_mappings_del(d, pci_bus_num(d->bus),
+            trace_pci_update_mappings_del(d, pci_dev_bus_num(d),
                                           PCI_SLOT(d->devfn),
                                           PCI_FUNC(d->devfn),
                                           i, r->addr, r->size);
@@ -1327,7 +1331,7 @@ static void pci_update_mappings(PCIDevice *d)
         }
         r->addr = new_addr;
         if (r->addr != PCI_BAR_UNMAPPED) {
-            trace_pci_update_mappings_add(d, pci_bus_num(d->bus),
+            trace_pci_update_mappings_add(d, pci_dev_bus_num(d),
                                           PCI_SLOT(d->devfn),
                                           PCI_FUNC(d->devfn),
                                           i, r->addr, r->size);
@@ -1446,9 +1450,9 @@ PCIINTxRoute pci_device_route_intx_to_irq(PCIDevice *dev, int pin)
     PCIBus *bus;
 
     do {
-         bus = dev->bus;
-         pin = bus->map_irq(dev, pin);
-         dev = bus->parent_dev;
+        bus = pci_get_bus(dev);
+        pin = bus->map_irq(dev, pin);
+        dev = bus->parent_dev;
     } while (dev);
 
     if (!bus->route_intx_to_irq) {
@@ -2018,7 +2022,6 @@ static void pci_qdev_realize(DeviceState *qdev, Error **errp)
     PCIDevice *pci_dev = (PCIDevice *)qdev;
     PCIDeviceClass *pc = PCI_DEVICE_GET_CLASS(pci_dev);
     Error *local_err = NULL;
-    PCIBus *bus;
     bool is_default_rom;
 
     /* initialize cap_present for pci_is_express() and pci_config_size() */
@@ -2026,8 +2029,7 @@ static void pci_qdev_realize(DeviceState *qdev, Error **errp)
         pci_dev->cap_present |= QEMU_PCI_CAP_EXPRESS;
     }
 
-    bus = PCI_BUS(qdev_get_parent_bus(qdev));
-    pci_dev = do_pci_register_device(pci_dev, bus,
+    pci_dev = do_pci_register_device(pci_dev,
                                      object_get_typename(OBJECT(qdev)),
                                      pci_dev->devfn, errp);
     if (pci_dev == NULL)
@@ -2320,7 +2322,7 @@ int pci_add_capability(PCIDevice *pdev, uint8_t cap_id,
                 error_setg(errp, "%s:%02x:%02x.%x "
                            "Attempt to add PCI capability %x at offset "
                            "%x overlaps existing capability %x at offset %x",
-                           pci_root_bus_path(pdev), pci_bus_num(pdev->bus),
+                           pci_root_bus_path(pdev), pci_dev_bus_num(pdev),
                            PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn),
                            cap_id, offset, overlapping_cap, i);
                 return -EINVAL;
@@ -2384,7 +2386,7 @@ static void pcibus_dev_print(Monitor *mon, DeviceState *dev, int indent)
 
     monitor_printf(mon, "%*sclass %s, addr %02x:%02x.%x, "
                    "pci id %04x:%04x (sub %04x:%04x)\n",
-                   indent, "", ctxt, pci_bus_num(d->bus),
+                   indent, "", ctxt, pci_dev_bus_num(d),
                    PCI_SLOT(d->devfn), PCI_FUNC(d->devfn),
                    pci_get_word(d->config + PCI_VENDOR_ID),
                    pci_get_word(d->config + PCI_DEVICE_ID),
@@ -2467,7 +2469,7 @@ static char *pcibus_get_dev_path(DeviceState *dev)
 
     /* Calculate # of slots on path between device and root. */;
     slot_depth = 0;
-    for (t = d; t; t = t->bus->parent_dev) {
+    for (t = d; t; t = pci_get_bus(t)->parent_dev) {
         ++slot_depth;
     }
 
@@ -2482,7 +2484,7 @@ static char *pcibus_get_dev_path(DeviceState *dev)
     /* Fill in slot numbers. We walk up from device to root, so need to print
      * them in the reverse order, last to first. */
     p = path + path_len;
-    for (t = d; t; t = t->bus->parent_dev) {
+    for (t = d; t; t = pci_get_bus(t)->parent_dev) {
         p -= slot_len;
         s = snprintf(slot, sizeof slot, ":%02x.%x",
                      PCI_SLOT(t->devfn), PCI_FUNC(t->devfn));
@@ -2530,12 +2532,12 @@ int pci_qdev_find_device(const char *id, PCIDevice **pdev)
 
 MemoryRegion *pci_address_space(PCIDevice *dev)
 {
-    return dev->bus->address_space_mem;
+    return pci_get_bus(dev)->address_space_mem;
 }
 
 MemoryRegion *pci_address_space_io(PCIDevice *dev)
 {
-    return dev->bus->address_space_io;
+    return pci_get_bus(dev)->address_space_io;
 }
 
 static void pci_device_class_init(ObjectClass *klass, void *data)
@@ -2563,11 +2565,11 @@ static void pci_device_class_base_init(ObjectClass *klass, void *data)
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev)
 {
-    PCIBus *bus = PCI_BUS(dev->bus);
+    PCIBus *bus = pci_get_bus(dev);
     PCIBus *iommu_bus = bus;
 
     while(iommu_bus && !iommu_bus->iommu_fn && iommu_bus->parent_dev) {
-        iommu_bus = PCI_BUS(iommu_bus->parent_dev->bus);
+        iommu_bus = pci_get_bus(iommu_bus->parent_dev);
     }
     if (iommu_bus && iommu_bus->iommu_fn) {
         return iommu_bus->iommu_fn(bus, iommu_bus->iommu_opaque, dev->devfn);
@@ -2638,7 +2640,7 @@ void pci_bus_get_w64_range(PCIBus *bus, Range *range)
 
 static bool pcie_has_upstream_port(PCIDevice *dev)
 {
-    PCIDevice *parent_dev = pci_bridge_get_device(dev->bus);
+    PCIDevice *parent_dev = pci_bridge_get_device(pci_get_bus(dev));
 
     /* Device associated with an upstream port.
      * As there are several types of these, it's easier to check the
@@ -2654,12 +2656,14 @@ static bool pcie_has_upstream_port(PCIDevice *dev)
 
 PCIDevice *pci_get_function_0(PCIDevice *pci_dev)
 {
+    PCIBus *bus = pci_get_bus(pci_dev);
+
     if(pcie_has_upstream_port(pci_dev)) {
         /* With an upstream PCIe port, we only support 1 device at slot 0 */
-        return pci_dev->bus->devices[0];
+        return bus->devices[0];
     } else {
         /* Other bus types might support multiple devices at slots 0-31 */
-        return pci_dev->bus->devices[PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 0)];
+        return bus->devices[PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 0)];
     }
 }
 
diff --git a/hw/pci/pci_bridge.c b/hw/pci/pci_bridge.c
index a47d257..b2e50c3 100644
--- a/hw/pci/pci_bridge.c
+++ b/hw/pci/pci_bridge.c
@@ -183,7 +183,7 @@ static void pci_bridge_init_vga_aliases(PCIBridge *br, PCIBus *parent,
 static PCIBridgeWindows *pci_bridge_region_init(PCIBridge *br)
 {
     PCIDevice *pd = PCI_DEVICE(br);
-    PCIBus *parent = pd->bus;
+    PCIBus *parent = pci_get_bus(pd);
     PCIBridgeWindows *w = g_new(PCIBridgeWindows, 1);
     uint16_t cmd = pci_get_word(pd->config + PCI_COMMAND);
 
@@ -214,7 +214,7 @@ static PCIBridgeWindows *pci_bridge_region_init(PCIBridge *br)
 static void pci_bridge_region_del(PCIBridge *br, PCIBridgeWindows *w)
 {
     PCIDevice *pd = PCI_DEVICE(br);
-    PCIBus *parent = pd->bus;
+    PCIBus *parent = pci_get_bus(pd);
 
     memory_region_del_subregion(parent->address_space_io, &w->alias_io);
     memory_region_del_subregion(parent->address_space_mem, &w->alias_mem);
@@ -339,7 +339,7 @@ void pci_bridge_reset(DeviceState *qdev)
 /* default qdev initialization function for PCI-to-PCI bridge */
 void pci_bridge_initfn(PCIDevice *dev, const char *typename)
 {
-    PCIBus *parent = dev->bus;
+    PCIBus *parent = pci_get_bus(dev);
     PCIBridge *br = PCI_BRIDGE(dev);
     PCIBus *sec_bus = &br->sec_bus;
 
diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 32191f2..6c91bd4 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -155,7 +155,8 @@ pcie_endpoint_cap_common_init(PCIDevice *dev, uint8_t offset, uint8_t cap_size)
      * a regular Endpoint type is exposed on a root complex.  These
      * should instead be Root Complex Integrated Endpoints.
      */
-    if (pci_bus_is_express(dev->bus) && pci_bus_is_root(dev->bus)) {
+    if (pci_bus_is_express(pci_get_bus(dev))
+        && pci_bus_is_root(pci_get_bus(dev))) {
         type = PCI_EXP_TYPE_RC_END;
     }
 
@@ -369,7 +370,7 @@ void pcie_cap_slot_hot_unplug_request_cb(HotplugHandler *hotplug_dev,
 {
     uint8_t *exp_cap;
     PCIDevice *pci_dev = PCI_DEVICE(dev);
-    PCIBus *bus = pci_dev->bus;
+    PCIBus *bus = pci_get_bus(pci_dev);
 
     pcie_cap_slot_hotplug_common(PCI_DEVICE(hotplug_dev), dev, &exp_cap, errp);
 
diff --git a/hw/pci/pcie_aer.c b/hw/pci/pcie_aer.c
index 21f896a..b009be7 100644
--- a/hw/pci/pcie_aer.c
+++ b/hw/pci/pcie_aer.c
@@ -409,7 +409,7 @@ static void pcie_aer_msg(PCIDevice *dev, const PCIEAERMsg *msg)
              */
             return;
         }
-        dev = pci_bridge_get_device(dev->bus);
+        dev = pci_bridge_get_device(pci_get_bus(dev));
     }
 }