Add support for reading the extended PCIe configuration space
Adds support for reading the PCIe extended configuration space, by reading the MCFG table provided by the new acpi:
scheme. If the scheme is available, which it is if and only if the "acpi" cargo feature is enabled for the kernel, pcid
will never call iopl
nor in
/out
, and solely rely on DMA.
Nothing that only resides in the extended configuration space is currently used, but it might be beneficial to implement AER at some point.