pci: Add root bus argument to pci_get_bus_devfn()

pci_get_bus_devfn() interprets a full PCI address string to give a PCIBus *
and device/function number within that bus.  Currently it assumes it is
working on an address under the primary PCI root bus.  This patch extends
it to allow the caller to specify a root bus.  This might seem a little odd
since the supplied address can (theoretically) include a PCI domain number.
However, attempting to use a non-zero domain number there is currently an
error, so that shouldn't really cause problems.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

hw/pci/pci-hotplug-old.c

diff --git a/hw/pci/pci-hotplug-old.c b/hw/pci/pci-hotplug-old.c
index e251810..e92d646 100644
--- a/hw/pci/pci-hotplug-old.c
+++ b/hw/pci/pci-hotplug-old.c
@@ -65,7 +65,7 @@
     PCIBus *bus;
     int ret, devfn;
 
-    bus = pci_get_bus_devfn(&devfn, devaddr);
+    bus = pci_get_bus_devfn(&devfn, pci_find_primary_bus(), devaddr);
     if (!bus) {
         monitor_printf(mon, "Invalid PCI device address %s\n", devaddr);
         return NULL;
@@ -205,7 +205,7 @@
         dinfo = NULL;
     }
 
-    bus = pci_get_bus_devfn(&devfn, devaddr);
+    bus = pci_get_bus_devfn(&devfn, pci_find_primary_bus(), devaddr);
     if (!bus) {
         monitor_printf(mon, "Invalid PCI device address %s\n", devaddr);
         return NULL;

hw/pci/pci.c

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 350b872..c4f63ad 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -589,12 +589,13 @@
     return 0;
 }
 
-PCIBus *pci_get_bus_devfn(int *devfnp, const char *devaddr)
+PCIBus *pci_get_bus_devfn(int *devfnp, PCIBus *root, const char *devaddr)
 {
-    PCIBus *root = pci_find_primary_bus();
     int dom, bus;
     unsigned slot;
 
+    assert(!root->parent_dev);
+
     if (!root) {
         fprintf(stderr, "No primary PCI bus\n");
         return NULL;
@@ -1588,7 +1589,7 @@
     if (i < 0)
         return NULL;
 
-    bus = pci_get_bus_devfn(&devfn, devaddr);
+    bus = pci_get_bus_devfn(&devfn, pci_find_primary_bus(), devaddr);
     if (!bus) {
         error_report("Invalid PCI device address %s for device %s",
                      devaddr, pci_nic_names[i]);

include/hw/pci/pci.h

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index e0597b7..3a43fba 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -394,7 +394,7 @@
 const char *pci_root_bus_path(PCIDevice *dev);
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn);
 int pci_qdev_find_device(const char *id, PCIDevice **pdev);
-PCIBus *pci_get_bus_devfn(int *devfnp, const char *devaddr);
+PCIBus *pci_get_bus_devfn(int *devfnp, PCIBus *root, const char *devaddr);
 
 int pci_parse_devaddr(const char *addr, int *domp, int *busp,
                       unsigned int *slotp, unsigned int *funcp);