Change in coreboot[master]: soc/intel/common/cpu: Use SoC overrides to set CPU privilege level

[Angel Pons (Code Review)]

Attention is currently required from: Jeff Daly, Mariusz Szafrański, Jonathan Zhang, Arthur Heymans, Andrey Petrov, Anjaneya "Reddy" Chagam, Subrata Banik, Johnny Lin, Tim Wawrzynczak, Christian Walter, Suresh Bellampalli, Vanessa Eusebio, Werner Zeh, Tim Chu.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/64806 )

Change subject: soc/intel/common/cpu: Use SoC overrides to set CPU privilege level
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Patch Set 4:

(1 comment)

File src/soc/intel/skylake/cpu.c:

https://review.coreboot.org/c/coreboot/+/64806/comment/9feabe71_11378d2d 
PS3, Line 40: if (!CONFIG(MAINBOARD_SUPPORTS_COFFEELAKE_CPU))
            : 		return;
            : 
            : 	msr_t msr;
            : 
            : 	msr = rdmsr(MSR_BIOS_DONE);
            : 	msr.lo |= ENABLE_IA_UNTRUSTED;
            : 	wrmsr(MSR_BIOS_DONE, msr);
> Ack

This check is because soc/intel/skylake code can be used with CFL CPUs when using AmberLakeFspBinPkg. This FSP is also used on LGA1151v2 (socket for CFL CPUs) boards with H310C, B365 and Z370 PCHs (these PCHs are actually rebranded 200 series PCHs, c.f. datasheet).

There are no boards using AmberLakeFspBinPkg right now, but I remember someone was working on porting a desktop board with a H310C PCH. And I have a Z370 board I haven't tried porting yet (I'm afraid of breaking it).

I agree that a runtime check would be preferable. I remember commenting about it on CB:60900 but I wasn't sure how to implement the check. I think some Amber Lake SoCs are based on CML, so there's a bunch of CPUIDs to consider.