Attention is currently required from: Dinesh Gehlot, Kapil Porwal, Nick Vaccaro.
Hello Dinesh Gehlot, Kapil Porwal, Nick Vaccaro,
I'd like you to reexamine a change. Please visit
https://review.coreboot.org/c/coreboot/+/82999?usp=email
to look at the new patch set (#2).
Change subject: soc/intel/adl: Skip RW CBFS ucode update if RO is locked ......................................................................
soc/intel/adl: Skip RW CBFS ucode update if RO is locked
This patch eliminates coreboot from loading microcode from RW CBFS (when the RO descriptor is locked, which indicates a fixed RO image) because the kernel can already patch the microcode on BSPs and APs while booting to OS.
This may be a chance to lower the burden on the AP FW side because patching microcode on in-field devices is subject to firmware updates, which are rarely published and, if required, must go through the firmware qualification testing procedure (which is costly, unlike kernel updates for ucode updates).
1. The FIT loads the necessary microcode from the RO during reset. 2. Reloading microcode from RW CBFS impacts boot time (~60ms, core-dependent). 3. The kernel can still load microcode updates.
ChromeOS devices leverage RO+RW-A/RW-B booting. The RO's microcode is sufficient for initial boot, and the kernel can apply updates later.
BUG=none TEST=Verified boot optimization; in-field devices skip RW-CBFS microcode loading when RO is locked.
Change-Id: I68953d45d3624aba0a3be28bc7b266b7621ddcc4 Signed-off-by: Subrata Banik subratabanik@google.com --- M src/soc/intel/alderlake/cpu.c 1 file changed, 22 insertions(+), 0 deletions(-)
git pull ssh://review.coreboot.org:29418/coreboot refs/changes/99/82999/2