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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>
This commit is contained in:
Michael S. Tsirkin 2010-11-24 07:23:25 +02:00
parent a5fce077b1
commit 929176c3b9
1 changed files with 24 additions and 13 deletions
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37
hw/pci.c
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@ -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 *pci_find_bus(PCIBus *bus, int bus_num)
{ {
PCIBus *sec; PCIBus *sec;
@ -1552,20 +1562,21 @@ PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
return bus; 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 */ /* try child bus */
if (!bus->parent_dev /* host pci bridge */ || for (; bus; bus = sec) {
(bus->parent_dev->config[PCI_SECONDARY_BUS] < bus_num && QLIST_FOREACH(sec, &bus->child, sibling) {
bus_num <= bus->parent_dev->config[PCI_SUBORDINATE_BUS])) { assert(sec->parent_dev);
for (; bus; bus = sec) { if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) {
QLIST_FOREACH(sec, &bus->child, sibling) { return sec;
assert(sec->parent_dev); }
if (sec->parent_dev->config[PCI_SECONDARY_BUS] == bus_num) { if (pci_secondary_bus_in_range(sec->parent_dev, bus_num)) {
return sec; break;
}
if (sec->parent_dev->config[PCI_SECONDARY_BUS] < bus_num &&
bus_num <= sec->parent_dev->config[PCI_SUBORDINATE_BUS]) {
break;
}
} }
} }
} }