VmxMechanisms.c File Reference

VMX based mechanisms. More...

#include "pch.h"

Functions
VOID	VmxMechanismCreateImmediateVmexitByVmxPreemptionTimer ()
	Create an immediate vm-exit after vm-entry by using VMX Preemption Timer.
VOID	VmxMechanismDisableImmediateVmexitByVmxPreemptionTimer ()
	Disable the immediate vm-exit after vm-entry by using VMX Preemption Timer.
VOID	VmxMechanismCreateImmediateVmexitBySelfIpi ()
	Create an immediate vm-exit after vm-entry by using self-ipi.
VOID	VmxMechanismCreateImmediateVmexit (VIRTUAL_MACHINE_STATE *VCpu)
	Create an immediate vm-exit after vm-entry.
VOID	VmxMechanismHandleImmediateVmexit (VIRTUAL_MACHINE_STATE *VCpu)
	Handle immediate vm-exit after vm-entry.

Detailed Description

VMX based mechanisms.

Author

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

Version

0.1

Date

2021-12-16

Copyright

This project is released under the GNU Public License v3.

Function Documentation

VmxMechanismCreateImmediateVmexit()

VOID VmxMechanismCreateImmediateVmexit

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Create an immediate vm-exit after vm-entry.

Parameters

CurrentCoreIndex

Returns

VOID

{
    //
    // I didn't test vm-exit by preemption timer as my machine
    // or maybe VMware workstation's nested virtualization didn't
    // support VMX Preemption Timer, that's why we use self-ipi
    // method by default
    //
 
    //
    // Indicate wait for an immediate vm-exit
    //
    VCpu->WaitForImmediateVmexit = TRUE;
 
    //
    // Self-ipi current core
    //
    VmxMechanismCreateImmediateVmexitBySelfIpi();
 
    //
    // Set vm-exit on external interrupts
    //
    HvSetExternalInterruptExiting(VCpu, TRUE);
}

VmxMechanismCreateImmediateVmexitBySelfIpi()

VOID VmxMechanismCreateImmediateVmexitBySelfIpi

(

)

Create an immediate vm-exit after vm-entry by using self-ipi.

Returns

VOID

{
    //
    // Send self-ipi on the target vector using xAPIC or x2APIC
    //
    ApicSelfIpi(IMMEDIATE_VMEXIT_MECHANISM_VECTOR_FOR_SELF_IPI);
}

VmxMechanismCreateImmediateVmexitByVmxPreemptionTimer()

VOID VmxMechanismCreateImmediateVmexitByVmxPreemptionTimer

(

)

Create an immediate vm-exit after vm-entry by using VMX Preemption Timer.

Returns

VOID

{
    //
    // Activate VMX preemption timer on pin-based controls
    //
    HvSetVmxPreemptionTimerExiting(TRUE);
 
    //
    // Setting VMX preemption timer to 0, cause and immediate
    // vm-exit and architecturally guarantees that no instruction
    // get a chance to be executed
    //
    CounterSetPreemptionTimer(0);
}

VmxMechanismDisableImmediateVmexitByVmxPreemptionTimer()

VOID VmxMechanismDisableImmediateVmexitByVmxPreemptionTimer

(

)

Disable the immediate vm-exit after vm-entry by using VMX Preemption Timer.

Returns

VOID

{
    CounterClearPreemptionTimer();
 
    //
    // Disable the VMX preemption timer on pin-based controls
    //
    HvSetVmxPreemptionTimerExiting(FALSE);
}

VmxMechanismHandleImmediateVmexit()

VOID VmxMechanismHandleImmediateVmexit

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Handle immediate vm-exit after vm-entry.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    //
    // Not waiting for immediate vm-exit anymore
    //
    VCpu->WaitForImmediateVmexit = FALSE;
 
    //
    // Set vm-exit on external interrupts
    //
    HvSetExternalInterruptExiting(VCpu, FALSE);
}