[S] Change in coreboot[main]: cpu/x86/smm: Pass full SMRAM region info to SMM runtime

[Shuo Liu (Code Review)]

Attention is currently required from: Angel Pons, Arthur Heymans, Christian Walter, Felix Held, Fred Reitberger, Jason Glenesk, Jeff Daly, Johnny Lin, Lean Sheng Tan, Matt DeVillier, Shuo Liu, Tim Chu, Vanessa Eusebio.

Shuo Liu has uploaded a new patch set (#5) to the change originally created by Benjamin Doron. ( https://review.coreboot.org/c/coreboot/+/80703?usp=email )

Change subject: cpu/x86/smm: Pass full SMRAM region info to SMM runtime
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cpu/x86/smm: Pass full SMRAM region info to SMM runtime

This data is used by smm_region_overlaps_handler(). Callers use this
helper to determine if it's safe to read/write to memory buffers taken
from untrusted input.

coreboot SMI handlers must not be confused into writing over any SMRAM
subregion, which includes the TSEG_STAGE_CACHE and chipset-specific area
(sometimes, IED), not just the handlers.

If stage cache writes were permitted, this could compromise the
integrity of the S3 resume path.

The consequences to overwriting the chipset-specific area are undefined.

Change-Id: Ibd9ed34fcfd77a4236b5cf122747a6718ce9c91f
Signed-off-by: Benjamin Doron 
---
M src/cpu/x86/smm/smm_module_loader.c
1 file changed, 8 insertions(+), 5 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/03/80703/5