[S] Change in coreboot[main]: soc/intel/cannonlake: Let coreboot program MSR_IA32_DEBUG_INTERFACE

[Krystian Hebel (Code Review)]

Attention is currently required from: Felix Singer, Filip Lewiński, Martin Roth, Michał Kopeć, Michał Żygowski, Paul Menzel.

Krystian Hebel has posted comments on this change by Michał Żygowski. ( https://review.coreboot.org/c/coreboot/+/83730?usp=email )

Change subject: soc/intel/cannonlake: Let coreboot program MSR_IA32_DEBUG_INTERFACE
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Patch Set 4:

(3 comments)

Commit Message:

https://review.coreboot.org/c/coreboot/+/83730/comment/62f113bc_b70625b6?usp... :
PS4, Line 7: Let coreboot program
With this change it is unconditionally locked, `let coreboot program` doesn't really convey that.

https://review.coreboot.org/c/coreboot/+/83730/comment/eb07af09_f2dda03d?usp... :
PS4, Line 9: Intel TXT requires the debug interface to be disabled. There is no
nit: I think it requires it to be in the same state as ACM, so debug ACM would expect it to be enabled. That said, there are no publicly available debug ACMs, so I'd say it is acceptable to have it unconditionally disabled.

File src/soc/intel/cannonlake/lockdown.c:

https://review.coreboot.org/c/coreboot/+/83730/comment/8e04b71e_45d5cb1a?usp... :
PS4, Line 10: #define MSR_IA32_DEBUG_INTERFACE		0xc80
This is architectural MSR, so it would fit in include/cpu/intel/msr.h better.