Kyösti Mälkki has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/34897 )
Change subject: arch/x86: Simplified postcar WB MTRR setup ......................................................................
Patch Set 1:
Patch Set 1:
Besides, that change of WB->WP might apply to TSEG region as well, so you can equally consider this commit as providing the region for WP instead of WB. Or WC instead of WB. The type does not matter as long as one type is satisfactory for the complete region.
You have asked if this CL will cause any issue on intel platform. Hence i thought of providing insight and asked to refer this this topic, specially https://review.coreboot.org/c/coreboot/+/34992/2 one as you will understand the implication of marking any region as WB and while tear down what happen, i would expect to see the same with this CL. I guess Aaron also said that WB might have its assumptions with LLC cache lines getting cleared due to uarch.
The code is not setting any additional MTRRs during romstage, only creating postcar_frame and having them applied after/at time of CAR teardown in the beginning of POSTCAR_STAGE. So far that has not been forbidden, right?