pci: Simplify pci_bus_is_root()

pci_bus_is_root() currently relies on a method in the PCIBusClass.
But it's always known if a PCI bus is a root bus when we create it, so
using a dynamic method is overkill.

This replaces it with an IS_ROOT bit in a new flags field, which is set on
root buses and otherwise clear.  As a bonus this removes the special
is_root logic from pci_expander_bridge, since it already creates its bus
as a root bus.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Message-Id: <20190424041959.4087-3-david@gibson.dropbear.id.au>

3 files changed, 3 insertions, 18 deletions

diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
index e62de4218f..ca66bc721a 100644
--- a/hw/pci-bridge/pci_expander_bridge.c
+++ b/hw/pci-bridge/pci_expander_bridge.c
@@ -66,11 +66,6 @@ static int pxb_bus_num(PCIBus *bus)
     return pxb->bus_nr;
 }
 
-static bool pxb_is_root(PCIBus *bus)
-{
-    return true; /* by definition */
-}
-
 static uint16_t pxb_bus_numa_node(PCIBus *bus)
 {
     PXBDev *pxb = convert_to_pxb(bus->parent_dev);
@@ -83,7 +78,6 @@ static void pxb_bus_class_init(ObjectClass *class, void *data)
     PCIBusClass *pbc = PCI_BUS_CLASS(class);
 
     pbc->bus_num = pxb_bus_num;
-    pbc->is_root = pxb_is_root;
     pbc->numa_node = pxb_bus_numa_node;
 }
 
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index a78023f669..b386777045 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -129,14 +129,9 @@ static void pci_bus_unrealize(BusState *qbus, Error **errp)
     vmstate_unregister(NULL, &vmstate_pcibus, bus);
 }
 
-static bool pcibus_is_root(PCIBus *bus)
-{
-    return !bus->parent_dev;
-}
-
 static int pcibus_num(PCIBus *bus)
 {
-    if (pcibus_is_root(bus)) {
+    if (pci_bus_is_root(bus)) {
         return 0; /* pci host bridge */
     }
     return bus->parent_dev->config[PCI_SECONDARY_BUS];
@@ -164,7 +159,6 @@ static void pci_bus_class_init(ObjectClass *klass, void *data)
     k->unrealize = pci_bus_unrealize;
     k->reset = pcibus_reset;
 
-    pbc->is_root = pcibus_is_root;
     pbc->bus_num = pcibus_num;
     pbc->numa_node = pcibus_numa_node;
     pbc->allows_extended_config_space = pcibus_allows_extended_config_space;
@@ -398,6 +392,7 @@ static void pci_root_bus_init(PCIBus *bus, DeviceState *parent,
     bus->slot_reserved_mask = 0x0;
     bus->address_space_mem = address_space_mem;
     bus->address_space_io = address_space_io;
+    bus->flags |= PCI_BUS_IS_ROOT;
 
     /* host bridge */
     QLIST_INIT(&bus->child);
@@ -415,11 +410,6 @@ bool pci_bus_is_express(PCIBus *bus)
     return object_dynamic_cast(OBJECT(bus), TYPE_PCIE_BUS);
 }
 
-bool pci_bus_is_root(PCIBus *bus)
-{
-    return PCI_BUS_GET_CLASS(bus)->is_root(bus);
-}
-
 bool pci_bus_allows_extended_config_space(PCIBus *bus)
 {
     return PCI_BUS_GET_CLASS(bus)->allows_extended_config_space(bus);
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 509c1ff555..9056cdfa3c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -20,6 +20,7 @@
 #include "standard-headers/linux/virtio_pci.h"
 #include "hw/virtio/virtio.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "hw/pci/msi.h"