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Kernel/PCI: Keep track of the currently mapped bus in MMIO mode

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There is a check in map_bus_region to make sure we don't pointlessly
remap the bus region if the previous mapping was for the same bus.
This is tracked with `m_mapped_bus`.

However, nothing was actually updating `m_mapped_bus`, and it is
initialised to 0. This means that if we start with a device on bus 0,
the read in data will be valid. If we map say bus 1 then bus 0 again,
the map for bus 0 will now be ignored and invalid data will be read in.

Fixed by updating `m_mapped_bus` with the currently mapped bus.
This commit is contained in:
Luke 2021-06-29 23:29:42 +01:00 committed by Andreas Kling
parent 02810f15b1
commit 37361821dd
1 changed files with 6 additions and 2 deletions
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8
Kernel/PCI/MMIOAccess.cpp
View file

@ -88,8 +88,10 @@ UNMAP_AFTER_INIT MMIOAccess::MMIOAccess(PhysicalAddress p_mcfg)
// Note: we need to map this region before enumerating the hardware and adding
// PCI::PhysicalID objects to the vector, because get_capabilities calls
// PCI::read16 which will need this region to be mapped.
m_mapped_region = MM.allocate_kernel_region(determine_memory_mapped_bus_region(0, m_segments.get(0).value().get_start_bus()), MEMORY_RANGE_PER_BUS, "PCI ECAM", Region::Access::Read | Region::Access::Write);
dbgln("PCI ECAM Mapped region @ {}", m_mapped_region->vaddr());
u8 start_bus = m_segments.get(0).value().get_start_bus();
m_mapped_region = MM.allocate_kernel_region(determine_memory_mapped_bus_region(0, start_bus), MEMORY_RANGE_PER_BUS, "PCI ECAM", Region::Access::Read | Region::Access::Write);
m_mapped_bus = start_bus;
dbgln_if(PCI_DEBUG, "PCI: First PCI ECAM Mapped region for starting bus {} @ {} {}", start_bus, m_mapped_region->vaddr(), m_mapped_region->physical_page(0)->paddr());
enumerate_hardware([&](const Address& address, ID id) {
m_physical_ids.append({ address, id, get_capabilities(address) });
@ -101,6 +103,8 @@ void MMIOAccess::map_bus_region(u32 segment, u8 bus)
if (m_mapped_bus == bus)
return;
m_mapped_region = MM.allocate_kernel_region(determine_memory_mapped_bus_region(segment, bus), MEMORY_RANGE_PER_BUS, "PCI ECAM", Region::Access::Read | Region::Access::Write);
m_mapped_bus = bus;
dbgln_if(PCI_DEBUG, "PCI: New PCI ECAM Mapped region for bus {} @ {} {}", bus, m_mapped_region->vaddr(), m_mapped_region->physical_page(0)->paddr());
}
VirtualAddress MMIOAccess::get_device_configuration_space(Address address)