tree b13c48e077f873749d96887ad6444961c5b5c8d2
parent 6b4522e2aa40b6c97929342716ad61e32a694cce
author Benjamin Doron <benjamin.doron@9elements.com> 1708487210 -0500
committer Arthur Heymans <arthur@aheymans.xyz> 1710915080 +0000

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 <benjamin.doron@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/80703
Reviewed-by: Shuo Liu <shuo.liu@intel.com>
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-by: Jérémy Compostella <jeremy.compostella@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>