Filter
Top Products
4-4 Vol. 3
PAGING
enable these modes and make transitions between them. The following items identify
certain limitations and other details:
• IA32_EFER.LME cannot be modified while paging is enabled (CR0.PG = 1).
Attempts to do so using WRMSR cause a general-protection exception (#GP(0)).
• Paging cannot be enabled (by setting CR0.PG to 1) while CR4.PAE = 0 and
IA32_EFER.LME = 1. Attempts to do so using MOV to CR0 cause a general-
protection exception (#GP(0)).
• CR4.PAE cannot be cleared while IA-32e paging is active (CR0.PG = 1 and
IA32_EFER.LME = 1). Attempts to do so using MOV to CR4 cause a general-
protection exception (#GP(0)).
Figure 4-1. Enabling and Changing Paging Modes
PG = 1
No Paging
PAE Paging
PAE = 1
LME = 0
PG = 0
PAE = 0
LME = 0
32-bit Paging
PG = 1
PAE = 0
LME = 0
PG = 0
PAE = 0
LME = 1
Set PG
Set PAE
Clear PAE
Clear PG
No Paging
PG = 0
PAE = 1
LME = 0
No Paging
PG = 1
IA-32e Paging
PAE = 1
LME = 1
Clear LME
Setr LME
PG = 0
PAE = 1
LME = 1
No Paging
Clear PAE
Set PAE
Clear PG
Set PG
Set PAE
Clear PAE
Setr LME
Clear LME
Clear PG
Set PG
#GP
Set LME
#GP
Set LME
#GP
Set PG
Clear PAE
#GP
Clear LME
#GP