[coreboot] Disabling ME >= 6.0 < 11 via the AltMeDisable bit

[Denis 'GNUtoo' Carikli]

Hi,

As I understand it:
- For ME < 6.0, the ME firmware can be removed totally, and still have
  a functional computer.
- For ME >= 6.0 (Nehalem) to ME < 11 (Broadwell), the All ME firmware
  can't be totally removed: the BUP module is required to have a
  functional computer. For such Firmware/Hardware versions the BUP does
  "Bringup (hardware initialization/configuration)"[1]
- For ME 11, the following modules are required to have a functional
  computer: RBE, BUP, kernel and syslib. For such generation, setting
  the HAP bit only tells the firmware not to load extra code (At that
  point the kernel is already loaded).

I've some questions regarding the above:
- Is there more details than "Bringup (hardware
  initialization/configuration)" for what the BUP partition does for
  the ME >= 6.0 and < 11.
- With the ME >= 6.0 and < 11, what does the AltMeDisable bit really
  do? Do we have some insights that tend to show that the execution is
  stopped, or not stopped?

References:
-----------
[1]https://recon.cx/2014/slides/Recon%202014%20Skochinsky.pdf

Denis.
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