[coreboot-gerrit] Change in coreboot[master]: cpu/x86/mpinit: Serialize microcode updates for HT threads

[Patrick Rudolph (Code Review)]

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Patrick Rudolph has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/49303 )

Change subject: cpu/x86/mpinit: Serialize microcode updates for HT threads
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Patch Set 4:

(1 comment)

File src/cpu/x86/sipi_vector.S:

https://review.coreboot.org/c/coreboot/+/49303/comment/177fa0fb_254c38f6 
PS4, Line 132: Assuming that only pre-FIT platforms with Hyper-Threading enabled and at
             : 	 * most 8 threads will ever run into this condition, the boot delay is negligible.
> Not necessarily true, ChromeOS platforms indeed have a copy of the uCode in FIT, but as that copy is […]

that is still true for chromeos as this code path would never be taken. The FIT loader will update microcode on APs with the RO version and this check will skip the microcode update as a microcode has been already loaded.
It is the updated in parallel in a later part of MPinit.