> No. CR4.LAM_SUP isn't an enablement switch over CR3.LAM_U{48,57},
> they're parallel relationship, CR4.LAM_SUP controls supervisor mode
> addresses has LAM or not while CR3.LAM_U controls user mode address's
> LAM enablement.
Unfortunately, the spec(the one in your cover letter) has a bug in
"10.1 ENUMERATION, ENABLING, AND CONFIGURATION":
CR4.LAM_SUP enables and configures LAM for supervisor pointers:
• If CR3.LAM_SUP = 0, LAM is not enabled for supervisor pointers.
• If CR3.LAM_SUP = 1, LAM is enabled for supervisor pointers with a width determined by the paging mode:
Based on the context, I think "CR3.LAM_SUP" should be "CR4.LAM_SUP".
I believe it could just be a typo. But it is confusing enough.
B.R.
Yu
