Intel 64 and IA-32 Architectures Software Developers Manual Volume 3B, System Programming Guide Part 2

Table Of Contents
B-34 Vol. 3
MODEL-SPECIFIC REGISTERS (MSRS)
B.2 MSRS IN THE INTEL
®
CORE
2 PROCESSOR FAMILY
Table B-3 lists model-specific registers (MSRs) for Intel Core 2 processor family and
for Intel Xeon processors based on Intel Core microarchitecture, architectural MSR
addresses are also included in Table B-3. These processors have a CPUID signature
with DisplayFamily_DisplayModel of 06_0FH, see Table B-1.
MSRs listed in Table B-2 and Table B-3 are also supported by processors based on the
Enhanced Intel Core microarchitecture. Processors based on the Enhanced Intel Core
microarchitecture have the CPUID signature DisplayFamily_DisplayModel of 06_17H.
The column “Shared/Unique” applies to multi-core processors based on Intel Core
microarchitecture. “Unique” means each processor core has a separate MSR, or a bit
C000_
0100H
IA32_FS_BASE Map of BASE Address of
FS. (R/W)
If
CPUID.80000001
.EDX.[bit 29] = 1
C000_
0101H
IA32_GS_BASE Map of BASE Address of
GS. (R/W)
If
CPUID.80000001
.EDX.[bit 29] = 1
C000_
0102H
IA32_KERNEL_GS_BASE Swap Target of BASE
Address of GS. (R/W)
If
CPUID.80000001
.EDX.[bit 29] = 1
C000_
0103H
259 IA32_TSC_AUX Auxiliary TSC (RW) If
CPUID.80000001
H: EDX[27] = 1
31:0 AUX: Auxiliary signature of
TSC
63:32 Reserved
NOTES:
1. In processors based on Intel NetBurst microarchitecture, MSR addresses 180H-197H are sup-
ported, software must treat them as model-specific. Starting with Intel Core Duo processors, MSR
addresses 180H-185H, 188H-197H are reserved.
2. In processors based on Intel NetBurst microarchitecture, MSR addresses 180H-197H are sup-
ported, software must treat them as model-specific. Starting with Intel Core Duo processors, MSR
addresses 180H-185H, 188H-197H are reserved.
3. The *_ADDR MSRs may or may not be present; this depends on flag settings in IA32_MCi_STATUS.
See Section 14.3.2.3 and Section 14.3.2.4 for more information.
Table B-2. IA-32 Architectural MSRs (Contd.)
Register Address Architectural MSR Name
and bit fields
(Former MSR Name) MSR/Bit Description
Introduced as
Architectural
MSR
Hex Decimal