x2apic.c File Reference

#include <hal.h>
#include <x86x64/Cpuid.h>
#include "x2apicp.h"
#include <debug.h>

Include dependency graph for x2apic.c:

Go to the source code of this file.

Macros
#define	NDEBUG

Functions
BOOLEAN NTAPI	X2ApicIsSupported (VOID)
	Checks whether the current processor supports x2APIC mode.
VOID NTAPI	X2ApicEnable (VOID)
	Switches the current processor's local APIC into x2APIC mode.

Macro Definition Documentation

NDEBUG

#define NDEBUG

Definition at line 14 of file x2apic.c.

Function Documentation

X2ApicEnable()

VOID NTAPI X2ApicEnable

(

VOID

)

Switches the current processor's local APIC into x2APIC mode.

Remarks

This must only be called after verifying support with X2ApicIsSupported, and before you try to do any MSR based register access.

Returns

None.

Definition at line 51 of file x2apic.c.

{
    X2APIC_BASE_ADDRESS_REGISTER BaseRegister;
 
    BaseRegister.LongLong = __readmsr(MSR_APIC_BASE);
 
    /* xAPIC (Enable) must already be set before x2APIC can be enabled */
    BaseRegister.Enable = 1;
    BaseRegister.EnableX2Apic = 1;
 
    __writemsr(MSR_APIC_BASE, BaseRegister.LongLong);
}

X2ApicIsSupported()

BOOLEAN NTAPI X2ApicIsSupported

(

VOID

)

Checks whether the current processor supports x2APIC mode.

Returns

TRUE if CPUID.01H:ECX.x2APIC[bit 21] is set, FALSE otherwise.

Definition at line 28 of file x2apic.c.

{
    CPUID_VERSION_INFO_REGS VersionInfo;
 
    __cpuid(VersionInfo.AsInt32, CPUID_VERSION_INFO);
 
    return VersionInfo.Ecx.Bits.x2APIC != 0;
}