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

[Jérémy Compostella (Code Review)]

Attention is currently required from: Felix Singer, Filip Lewiński, Intel coreboot Reviewers, Krystian Hebel, Martin Roth, Michał Kopeć, Michał Żygowski, Paul Menzel.

Jérémy Compostella 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 lock MSR_IA32_DEBUG_INTERFACE
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Patch Set 6:

(4 comments)

File src/include/cpu/intel/msr.h:

https://review.coreboot.org/c/coreboot/+/83730/comment/147ef20d_96695831?usp... :
PS6, Line 19: #define MSR_IA32_DEBUG_INTERFACE		0xc80
It seems to be an extra tab
It also seems to be places between `MSR_BOOT_GUARD_SACM_INFO` and its bits definition.

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

https://review.coreboot.org/c/coreboot/+/83730/comment/dc1af6a1_38b8e447?usp... :
PS6, Line 11: #define   MSR_IA32_DEBUG_INTERFACE_EN		(1 << 0)
            : #define   MS
Shouldn't it be in src/include/cpu/intel/msr.h ?
Shouldn't it use the BIT macro ?

https://review.coreboot.org/c/coreboot/+/83730/comment/6ff3a860_6f7bb87b?usp... :
PS6, Line 14: static void cpu_lockdown_cfg(void)
Could it be called `lock_debug_interface` instead ?

https://review.coreboot.org/c/coreboot/+/83730/comment/4ffb44e5_efcf5298?usp... :
PS6, Line 18: 	if (!(msr.lo & MSR_IA32_DEBUG_INTERFACE_LOCK)) {
```
if (msr.lo & MSR_IA32_DEBUG_INTERFACE_LOCK)
      return;

if (CONFIG(INTEL_TXT))
      msr.lo &= ~MSR_IA32_DEBUG_INTERFACE_EN;

msr.lo |= MSR_IA32_DEBUG_INTERFACE_LOCK;
wrmsr(MSR_IA32_DEBUG_INTERFACE, msr);
```