commit 9bc473057db773dd24be381ccbde4c686595d2e7
author David Gibson <david@gibson.dropbear.id.au> Thu Jun 06 18:48:52 2013 +1000
committer Michael S. Tsirkin <mst@redhat.com> Sun Jul 07 23:10:57 2013 +0300
tree c0da77accb6351485563acb9dd9a45416acc6b1b
parent 29b358f93a48a415853d11fc9b02f711b5ec8f76

pci: Simpler implementation of primary PCI bus

Currently pci_find_primary_bus() searches the list of root buses for one
with domain 0.  But since host buses are always registered with domain 0,
this just amounts to finding the only PCI host bus.  The only remaining
users of pci_find_primary_bus() are in pci-hotplug-old.c, which implements
the old style pci_add/pci_del commands.

Therefore, this patch redefines pci_find_primary_bus() to find the only
PCI root bus, returning an error if there are multiple roots.  The callers
in pci-hotplug-old.c are updated correspondingly, to produce sensible
error messages.

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 807260c..8077289 100644
--- a/hw/pci/pci-hotplug-old.c
+++ b/hw/pci/pci-hotplug-old.c
@@ -62,10 +62,17 @@
 {
     Error *local_err = NULL;
     QemuOpts *opts;
+    PCIBus *root = pci_find_primary_bus();
     PCIBus *bus;
     int ret, devfn;
 
-    bus = pci_get_bus_devfn(&devfn, pci_find_primary_bus(), devaddr);
+    if (!root) {
+        monitor_printf(mon, "no primary PCI bus (if there are multiple"
+                       " PCI roots, you must use device_add instead)");
+        return NULL;
+    }
+
+    bus = pci_get_bus_devfn(&devfn, root, devaddr);
     if (!bus) {
         monitor_printf(mon, "Invalid PCI device address %s\n", devaddr);
         return NULL;
@@ -92,8 +99,7 @@
         monitor_printf(mon, "Parameter addr not supported\n");
         return NULL;
     }
-    return pci_nic_init(&nd_table[ret], pci_find_primary_bus(),
-                        "rtl8139", devaddr);
+    return pci_nic_init(&nd_table[ret], root, "rtl8139", devaddr);
 }
 
 static int scsi_hot_add(Monitor *mon, DeviceState *adapter,
@@ -144,7 +150,8 @@
     switch (dinfo->type) {
     case IF_SCSI:
         if (!root) {
-            monitor_printf(mon, "no primary PCI bus\n");
+            monitor_printf(mon, "no primary PCI bus (if there are multiple"
+                           " PCI roots, you must use device_add instead)");
             goto err;
         }
         if (pci_read_devaddr(mon, pci_addr, &pci_bus, &slot)) {
@@ -177,6 +184,7 @@
     DriveInfo *dinfo = NULL;
     int type = -1;
     char buf[128];
+    PCIBus *root = pci_find_primary_bus();
     PCIBus *bus;
     int devfn;
 
@@ -206,7 +214,12 @@
         dinfo = NULL;
     }
 
-    bus = pci_get_bus_devfn(&devfn, pci_find_primary_bus(), devaddr);
+    if (!root) {
+        monitor_printf(mon, "no primary PCI bus (if there are multiple"
+                       " PCI roots, you must use device_add instead)");
+        return NULL;
+    }
+    bus = pci_get_bus_devfn(&devfn, root, devaddr);
     if (!bus) {
         monitor_printf(mon, "Invalid PCI device address %s\n", devaddr);
         return NULL;
@@ -293,7 +306,8 @@
     Error *local_err = NULL;
 
     if (!root) {
-        monitor_printf(mon, "no primary PCI bus\n");
+        monitor_printf(mon, "no primary PCI bus (if there are multiple"
+                       " PCI roots, you must use device_del instead)");
         return -1;
     }
 

hw/pci/pci.c

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 2f2db0f..e0995aa 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -249,15 +249,18 @@
 
 PCIBus *pci_find_primary_bus(void)
 {
+    PCIBus *primary_bus = NULL;
     struct PCIHostBus *host;
 
     QLIST_FOREACH(host, &host_buses, next) {
-        if (host->domain == 0) {
-            return host->bus;
+        if (primary_bus) {
+            /* We have multiple root buses, refuse to select a primary */
+            return NULL;
         }
+        primary_bus = host->bus;
     }
 
-    return NULL;
+    return primary_bus;
 }
 
 PCIBus *pci_device_root_bus(const PCIDevice *d)