[coreboot-gerrit] Change in coreboot[master]: cpu/x86/smm/smm_stub: Add x86_64 support

[Angel Pons (Code Review)]

Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/37392 )

Change subject: cpu/x86/smm/smm_stub: Add x86_64 support
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Patch Set 4:
> Patch Set 4:
> > Patch Set 4: Code-Review-1
> >
> > (1 comment)
> >
> > For security reasons, the page tables used in SMM must be located in SMRAM.
>
> Please explain your threat model and why it is a security issue if the page table are not in SMRAM.

I imagine it is because th SMM page tables can then be accessed from outside SMM, which could be exploited to escalate privileges to SMM. Which would not be fun.