soc/intel/common: Merge TME new key gen and exclusion range configs

Merge TME_KEY_REGENERATION_ON_WARM_BOOT and
TME_EXCLUDE_CBMEM_ENCRYPTION config options under new config option
named TME_KEY_REGENERATION_ON_WARM_BOOT.

Program Intel TME to generate a new key for each warm boot. TME always
generates a new key on each cold boot. With this option enabled TME
generates a new key even in warm boot. Without this option TME reuses
the key for warm boot.

If a new key is generated on warm boot, DRAM contents from previous
warm boot will not get decrypted. This creates issue in accessing
CBMEM region from previous warm boot. To mitigate the issue coreboot
also programs exclusion range. Intel TME does not encrypt physical
memory range set in exclusion range. Current coreboot implementation
programs TME to exclude CBMEM region. When this config option is
enabled, coreboot instructs Intel FSP to program TME to generate
a new key on every warm boot and also exclude CBMEM region from being
encrypted by TME.

BUG=b:276120526
TEST=Able to build rex.

Change-Id: I19d9504229adb1abff2ef394c4ca113c335099c2
Signed-off-by: Pratikkumar Prajapati <pratikkumar.v.prajapati@intel.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/76879
Reviewed-by: Sridhar Siricilla <sridhar.siricilla@intel.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

0 files changed, 0 insertions, 0 deletions