Commit 929176c3 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
parent a5fce077

hw/pci.c

+24 −13
Original line number Diff line number Diff line
@@ -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;
@@ -1552,23 +1562,24 @@ 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]) {

            if (pci_secondary_bus_in_range(sec->parent_dev, bus_num)) {

                break;

            }

        }

    }

    }



    return NULL;

}