Change in coreboot[master]: [RFC|WIP] soc/intel/skylake: replace native SGX initialization by FSP
Michael Niewöhner has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/44244 )
Change subject: [RFC|WIP] soc/intel/skylake: replace native SGX initialization by FSP ......................................................................
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if i remember correctly, this programming sequence requirement was from cannon-lake onwards. skylake/kabylake can still use native (coreboot) sgx init flow.
On SKL LT_MEMORY_LOCK has to be set, too, and FSP does this with SkipMpInit=0. AFAICT native SGX init can't be used on SKL for the same reasons we can't use it on CNL.
From cannon-lake onwards, sgx init needs fsp for the reasons mentioned in https://review.coreboot.org/c/coreboot/+/36356/2/src/soc/intel/cannonlake/fi.... i guess mp-ppi may also be used for cannon-lake onwards. Please follow Nate's recommendation for that.
PS: I see my gmail was added earlier and that notification was in spam. Thanks for adding my @intel email. I am off next week, I’ll respond the following week if there are follow-up questions.
See CB:36356. Native SGX init is not used in CNL, so there is nothing more to do.
"FSP-S must be able to write and lock some registers that would be immutable after setting LT_LOCK_MEMORY."* I dont think i got into this issue when i wrote native sgx init flow. At that time i was able to activate the SGX and lock it correctly by using native code only. i created enclaves also from the application and checked it was encrypted and working as expected.
@Nate: is this* valid for SKL/KBL as well?
Yes, this is valid and exactly the point, why native SGX init can't be used. LT_MEMORY_LOCK must be set, *before* native SGX init (well, more specifically before microcode reload). That conflicts with the requirement of FSP-S to be able to write registers.
At that time i was able to activate the SGX and lock it correctly by using native code only. i created enclaves also from the application and checked it was encrypted and working as expected
Yes, SGX works. No, not in a secure way with native SGX init without LT_MEMORY_LOCK.
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Michael Niewöhner (Code Review)