[coreboot-gerrit] Change in coreboot[master]: cpu/x86/smm: Add support for long mode

[Arthur Heymans (Code Review)]

Arthur Heymans has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/35681 )

Change subject: cpu/x86/smm: Add support for long mode
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Patch Set 5:

(3 comments)

Do you want SMM to rely on a RO component (pagetable)? Wouldn't copying it in ASEG/TSEG be a better idea?

https://review.coreboot.org/c/coreboot/+/35681/5/src/cpu/x86/smm/smmhandler.... 
File src/cpu/x86/smm/smmhandler.S:

https://review.coreboot.org/c/coreboot/+/35681/5/src/cpu/x86/smm/smmhandler.... 
PS5, Line 198: MSR registers
Why can't that MSR be accessed in 64bit mode?

https://review.coreboot.org/c/coreboot/+/35681/5/src/cpu/x86/smm/smmhandler.... 
PS5, Line 219: /* Disable paging */
             : 	movl	%cr0, %eax
             : 	andl	$0x7FFFFFFF, %eax
             : 	movl	%eax, %cr0
Isn't this covered by the savestate?

https://review.coreboot.org/c/coreboot/+/35681/5/src/cpu/x86/smm/smmhandler.... 
PS5, Line 229: 
             : 	/* Disable PAE */
             : 	movl	%cr4, %eax
             : 	andl	$(~0x20), %eax
             : 	movl	%eax, %cr4
Isn't this covered by the savestate?