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authorMichael S. Tsirkin <mst@redhat.com>2010-11-24 07:23:25 +0200
committerMichael S. Tsirkin <mst@redhat.com>2010-11-24 17:04:59 +0200
commit929176c3b9f8d5feec9395401f889a3bfb95e816 (patch)
treec6453196872085bbd7ed6a44eaccedd16f207e5d /hw
parenta5fce077b134a486794b77b49f4eae1d3c9b960c (diff)
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pci: fix bus walk under secondary bus reset
Take into account secondary bus reset bit for bus walk: devices behind a reset bus should not respond to configuration cycles. Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r--hw/pci.c37
1 files changed, 24 insertions, 13 deletions
diff --git a/hw/pci.c b/hw/pci.c
index d02f980..0c15b13 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1540,6 +1540,16 @@ void pci_bridge_update_mappings(PCIBus *b)
}
}
+/* Whether a given bus number is in range of the secondary
+ * bus of the given bridge device. */
+static bool pci_secondary_bus_in_range(PCIDevice *dev, int bus_num)
+{
+ return !(pci_get_word(dev->config + PCI_BRIDGE_CONTROL) &
+ PCI_BRIDGE_CTL_BUS_RESET) /* Don't walk the bus if it's reset. */ &&
+ dev->config[PCI_SECONDARY_BUS] < bus_num &&
+ bus_num <= dev->config[PCI_SUBORDINATE_BUS];
+}
+
PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
{
PCIBus *sec;
@@ -1552,20 +1562,21 @@ PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
return bus;
}
+ /* Consider all bus numbers in range for the host pci bridge. */
+ if (bus->parent_dev &&
+ !pci_secondary_bus_in_range(bus->parent_dev, bus_num)) {
+ return NULL;
+ }
+
/* try child bus */
- if (!bus->parent_dev /* host pci bridge */ ||
- (bus->parent_dev->config[PCI_SECONDARY_BUS] < bus_num &&
- bus_num <= bus->parent_dev->config[PCI_SUBORDINATE_BUS])) {
- for (; bus; bus = sec) {
- QLIST_FOREACH(sec, &bus->child, sibling) {
- assert(sec->parent_dev);
- if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) {
- return sec;
- }
- if (sec->parent_dev->config[PCI_SECONDARY_BUS] < bus_num &&
- bus_num <= sec->parent_dev->config[PCI_SUBORDINATE_BUS]) {
- break;
- }
+ for (; bus; bus = sec) {
+ QLIST_FOREACH(sec, &bus->child, sibling) {
+ assert(sec->parent_dev);
+ if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) {
+ return sec;
+ }
+ if (pci_secondary_bus_in_range(sec->parent_dev, bus_num)) {
+ break;
}
}
}