Change in coreboot[master]: intel/block/cpu: Keep flash region cached until the payload is loaded

[Subrata Banik (Code Review)]

Attention is currently required from: Arthur Heymans, Patrick Georgi, Maulik V Vaghela, Rizwan Qureshi, Sridhar Siricilla, Lean Sheng Tan, Werner Zeh, Angel Pons, Patrick Rudolph.
Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/62566 )

Change subject: intel/block/cpu: Keep flash region cached until the payload is loaded
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Patch Set 2:

(1 comment)

File src/soc/intel/common/block/cpu/mp_init.c:

https://review.coreboot.org/c/coreboot/+/62566/comment/5bd81b82_b7e31fae 
PS2, Line 164: MP_SERVICES_PPI
> Could you elaborate a bit more on this? At which time did you output this log? Right after the call to 'mp_run_on_all_cpus(&wrapper_x86_setup_mtrrs, NULL)' or before?

Please ignore my last comment, I had took earlier snapshot, I could see the ROM is not cached with ToT as well (but I don't see the sluggishness)

[DEBUG]  0x0000000000000006: PHYBASE0: Address = 0x0000000000000000, WB
[DEBUG]  0x00003fff80000800: PHYMASK0: Length  = 0x0000000080000000, Valid
[DEBUG]  0x0000000077000000: PHYBASE1: Address = 0x0000000077000000, UC
[DEBUG]  0x00003fffff000800: PHYMASK1: Length  = 0x0000000001000000, Valid
[DEBUG]  0x0000000078000000: PHYBASE2: Address = 0x0000000078000000, UC
[DEBUG]  0x00003ffff8000800: PHYMASK2: Length  = 0x0000000008000000, Valid
[DEBUG]  0x0000000090000001: PHYBASE3: Address = 0x0000000090000000, WC
[DEBUG]  0x00003ffff0000800: PHYMASK3: Length  = 0x0000000010000000, Valid
[DEBUG]  0x0000000100000006: PHYBASE4: Address = 0x0000000100000000, WB
[DEBUG]  0x00003fff00000800: PHYMASK4: Length  = 0x0000000100000000, Valid
[DEBUG]  0x0000000200000006: PHYBASE5: Address = 0x0000000200000000, WB
[DEBUG]  0x00003fff80000800: PHYMASK5: Length  = 0x0000000080000000, Valid
[DEBUG]  0x000000027fc00000: PHYBASE6: Address = 0x000000027fc00000, UC
[DEBUG]  0x00003fffffc00800: PHYMASK6: Length  = 0x0000000000400000, Valid
[DEBUG]  0x0000000000000000: PHYBASE7
[DEBUG]  0x0000000000000000: PHYMASK7: Disabled
[DEBUG]  0x0000000000000000: PHYBASE8
[DEBUG]  0x0000000000000000: PHYMASK8: Disabled
[DEBUG]  0x0000000000000000: PHYBASE9
[DEBUG]  0x0000000000000000: PHYMASK9: Disabled

but after cherry picking your CL, it become dead slow.