CrossVmexits.c File Reference

The functions for passing vm-exits in vmx root. More...

#include "pch.h"

Functions
VOID	VmxHandleXsetbv (VIRTUAL_MACHINE_STATE *VCpu)
	Handling XSETBV Instruction vm-exits.
VOID	VmxHandleVmxPreemptionTimerVmexit (VIRTUAL_MACHINE_STATE *VCpu)
	Handling VMX Preemption Timer vm-exits.
VOID	VmxHandleTripleFaults (VIRTUAL_MACHINE_STATE *VCpu)
	Handling triple fault VM-exits.

Detailed Description

The functions for passing vm-exits in vmx root.

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

VmxHandleTripleFaults()

VOID VmxHandleTripleFaults

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Handling triple fault VM-exits.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    LogError("Err, triple fault error occurred!");
 
    //
    // This error cannot be recovered, produce debug results
    //
    CommonWriteDebugInformation(VCpu);
 
    //
    // We won't further continue after this error
    //
    DbgBreakPoint();
}

VmxHandleVmxPreemptionTimerVmexit()

VOID VmxHandleVmxPreemptionTimerVmexit

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Handling VMX Preemption Timer vm-exits.

Parameters

VCpu	The virtual processor's state

Returns

VOID

{
    LogError("Why vm-exit for VMX preemption timer happened?");
 
    //
    // Not increase the RIP by default
    //
    HvSuppressRipIncrement(VCpu);
}

VmxHandleXsetbv()

VOID VmxHandleXsetbv

(

VIRTUAL_MACHINE_STATE *

VCpu

)

Handling XSETBV Instruction vm-exits.

Parameters

VCpu

Returns

VOID

{
    CPUID_EAX_01         CpuidInfo;
    VMX_SEGMENT_SELECTOR GuestCs  = GetGuestCs();
    UINT32               XCrIndex = VCpu->Regs->rcx & 0xffffffff;
    XCR0                 XCr0     = {.AsUInt = VCpu->Regs->rdx << 32 | VCpu->Regs->rax};
    CR4                  GuestCr4 = {.AsUInt = GetGuestCr4()};
 
    if (XCrIndex != 0 || GuestCs.Attributes.DescriptorPrivilegeLevel != 0 || !CommonIsXCr0Valid(XCr0))
    {
        EventInjectGeneralProtection();
        return;
    }
 
    CommonCpuidInstruction(CPUID_VERSION_INFORMATION, 0, (INT32 *)&CpuidInfo);
 
    if (CpuidInfo.CpuidFeatureInformationEcx.XsaveXrstorInstruction == 0 || GuestCr4.OsXsave == 0)
    {
        EventInjectUndefinedOpcode(VCpu);
        return;
    }
 
    _xsetbv(XCrIndex, XCr0.AsUInt);
}