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Kernel/PCI: Don't try to enumerate 255 functions on the host bridge

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There can only be a limited number of functions (only 8).
Also, consider the start bus of the PCI domain when trying to enumerate
other host bridges on bus 0, device 0, functions 1-7 (function 0 is the
main host bridge).
This commit is contained in:
Liav A 2022-01-15 09:15:46 +02:00 • committed by Idan Horowitz
parent 518473846a
commit c1d3b557d5
Notes: sideshowbarker 2024-07-17 20:38:27 +09:00
1 changed files with 8 additions and 5 deletions
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13
Kernel/Bus/PCI/Controller/HostBridge.cpp
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@ -109,19 +109,22 @@ UNMAP_AFTER_INIT void HostBridge::enumerate_attached_devices(Function<void(Devic
m_enumerated_buses.set(m_domain.start_bus(), true);
enumerate_bus(callback, m_domain.start_bus(), true);
// Handle Multiple PCI host bridges on slot 0, device 0.
// Handle Multiple PCI host bridges on bus 0, device 0, functions 1-7 (function 0
// is the main host bridge).
// If we happen to miss some PCI buses because they are not reachable through
// recursive PCI-to-PCI bridges starting from bus 0, we might find them here.
if ((read8_field(0, 0, 0, PCI::RegisterOffset::HEADER_TYPE) & 0x80) != 0) {
for (int bus_as_function_number = 1; bus_as_function_number < 256; ++bus_as_function_number) {
for (int bus_as_function_number = 1; bus_as_function_number < 8; ++bus_as_function_number) {
if (read16_field(0, 0, bus_as_function_number, PCI::RegisterOffset::VENDOR_ID) == PCI::none_value)
continue;
if (read16_field(0, 0, bus_as_function_number, PCI::RegisterOffset::CLASS) != 0x6)
continue;
if (m_enumerated_buses.get(bus_as_function_number))
if (Checked<u8>::addition_would_overflow(m_domain.start_bus(), bus_as_function_number))
break;
if (m_enumerated_buses.get(m_domain.start_bus() + bus_as_function_number))
continue;
enumerate_bus(callback, bus_as_function_number, false);
m_enumerated_buses.set(bus_as_function_number, true);
enumerate_bus(callback, m_domain.start_bus() + bus_as_function_number, false);
m_enumerated_buses.set(m_domain.start_bus() + bus_as_function_number, true);
}
}
}