Counters.c File Reference

The functions for emulating counters. More...

#include "pch.h"

Functions
VOID	CounterEmulateRdtsc (VIRTUAL_MACHINE_STATE *VCpu)
	Emulate RDTSC.
VOID	CounterEmulateRdtscp (VIRTUAL_MACHINE_STATE *VCpu)
	Emulate RDTSCP.
VOID	CounterEmulateRdpmc (VIRTUAL_MACHINE_STATE *VCpu)
	Emulate RDPMC.
VOID	CounterSetPreemptionTimer (UINT32 TimerValue)
	Set the timer value for preemption timer.
VOID	CounterClearPreemptionTimer ()
	Clears the preemption timer.

Detailed Description

The functions for emulating counters.

Author

Sina Karvandi (sina@.nosp@m.hype.nosp@m.rdbg..nosp@m.org)

Version

0.1

Date

2020-06-14

Copyright

This project is released under the GNU Public License v3.

Function Documentation

CounterClearPreemptionTimer()

VOID CounterClearPreemptionTimer

(

)

Clears the preemption timer.

Returns

VOID

{
    //
    // Set the time value to NULL
    //
    VmxVmwrite64(VMCS_GUEST_VMX_PREEMPTION_TIMER_VALUE, NULL64_ZERO);
}

CounterEmulateRdpmc()

VOID CounterEmulateRdpmc

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Emulate RDPMC.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    UINT32      EcxReg    = 0;
    PGUEST_REGS GuestRegs = VCpu->Regs;
 
    EcxReg         = GuestRegs->rcx & 0xffffffff;
    UINT64 Pmc     = __readpmc(EcxReg);
    GuestRegs->rax = 0x00000000ffffffff & Pmc;
    GuestRegs->rdx = 0x00000000ffffffff & (Pmc >> 32);
}

CounterEmulateRdtsc()

VOID CounterEmulateRdtsc

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Emulate RDTSC.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    //
    // I realized that if you log anything here (LogInfo) then
    // the system-halts, currently don't have any idea of how
    // to solve it, in the future we solve it using tsc offsetting
    // or tsc scalling (The reason is because of that fucking patchguard :( )
    //
    UINT64      Tsc       = __rdtsc();
    PGUEST_REGS GuestRegs = VCpu->Regs;
 
    GuestRegs->rax = 0x00000000ffffffff & Tsc;
    GuestRegs->rdx = 0x00000000ffffffff & (Tsc >> 32);
}

CounterEmulateRdtscp()

VOID CounterEmulateRdtscp

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Emulate RDTSCP.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    UINT32      Aux       = 0;
    UINT64      Tsc       = __rdtscp(&Aux);
    PGUEST_REGS GuestRegs = VCpu->Regs;
 
    GuestRegs->rax = 0x00000000ffffffff & Tsc;
    GuestRegs->rdx = 0x00000000ffffffff & (Tsc >> 32);
 
    GuestRegs->rcx = 0x00000000ffffffff & Aux;
}

CounterSetPreemptionTimer()

VOID CounterSetPreemptionTimer

(

UINT32

TimerValue

)

Set the timer value for preemption timer.

Parameters

TimerValue

Value of the timer

Returns

VOID

{
    //
    // Set the time value
    //
    VmxVmwrite64(VMCS_GUEST_VMX_PREEMPTION_TIMER_VALUE, TimerValue);
}