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bluepill/exit_handler.cpp

155 lines
3.9 KiB

4 years ago
#include "vmxexit_handler.h"
auto exit_handler(hv::pguest_registers regs) -> void
{
u64 exit_reason;
__vmx_vmread(VMCS_EXIT_REASON, &exit_reason);
switch (exit_reason)
{
case VMX_EXIT_REASON_EXECUTE_CPUID:
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{
if (regs->rcx == 0xC0FFEE)
{
__try
{
*(u8*)0x0 = 0xDE;
}
__except (EXCEPTION_EXECUTE_HANDLER)
{
regs->rax = 0xC0FFEE;
break;
}
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}
else
{
int result[4];
__cpuid(result, regs->rax);
regs->rax = result[0];
regs->rbx = result[1];
regs->rcx = result[2];
regs->rdx = result[3];
}
break;
}
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case VMX_EXIT_REASON_EXECUTE_XSETBV:
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{
hv::msr_split value{};
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value.high = regs->rdx;
value.low = regs->rax;
__try
{
/*
EXCEPTION WARNING:
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#GP If the current privilege level is not 0.
If an invalid XCR is specified in ECX.
If the value in EDX:EAX sets bits that are reserved in the XCR specified by ECX.
If an attempt is made to clear bit 0 of XCR0.
If an attempt is made to set XCR0[2:1] to 10b.
#UD If CPUID.01H:ECX.XSAVE[bit 26] = 0.
If CR4.OSXSAVE[bit 18] = 0.
If the LOCK prefix is used.
*/
_xsetbv(regs->rcx, value.value);
break;
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}
__except (EXCEPTION_EXECUTE_HANDLER)
{
vmentry_interrupt_information interrupt{};
interrupt.flags = interruption_type::hardware_exception;
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interrupt.vector = EXCEPTION_GP_FAULT;
interrupt.valid = true;
__vmx_vmwrite(VMCS_CTRL_VMENTRY_INTERRUPTION_INFORMATION_FIELD, interrupt.flags);
}
return; // dont advance rip...
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}
case VMX_EXIT_REASON_EXECUTE_RDMSR:
{
__try
{
/*
EXCEPTION WARNING:
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#GP(0) If the current privilege level is not 0.
If the value in ECX specifies a reserved or unimplemented MSR address.
#UD If the LOCK prefix is used.
*/
const auto result =
hv::msr_split{ __readmsr(regs->rcx) };
regs->rdx = result.high;
regs->rax = result.low;
break;
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}
__except (EXCEPTION_EXECUTE_HANDLER)
{
vmentry_interrupt_information interrupt{};
interrupt.flags = interruption_type::hardware_exception;
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interrupt.vector = EXCEPTION_GP_FAULT;
interrupt.valid = true;
__vmx_vmwrite(VMCS_CTRL_VMENTRY_INTERRUPTION_INFORMATION_FIELD, interrupt.flags);
}
return; // dont advance rip...
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}
case VMX_EXIT_REASON_EXECUTE_WRMSR:
{
hv::msr_split value;
value.low = regs->rax;
value.high = regs->rdx;
__try
{
__writemsr(regs->rcx, value.value);
break;
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}
__except (EXCEPTION_EXECUTE_HANDLER)
{
/*
EXCEPTION WARNING:
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#GP(0) If the current privilege level is not 0.
If the value in ECX specifies a reserved or unimplemented MSR address.
#UD If the LOCK prefix is used.
*/
vmentry_interrupt_information interrupt{};
interrupt.flags = interruption_type::hardware_exception;
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interrupt.vector = EXCEPTION_GP_FAULT;
interrupt.valid = true;
__vmx_vmwrite(VMCS_CTRL_VMENTRY_INTERRUPTION_INFORMATION_FIELD, interrupt.flags);
}
return; // dont advance rip...
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}
case VMX_EXIT_REASON_EXECUTE_INVD:
{
// couldnt find the intrin for this so i just made one...
// probably could have used __wbinvd?
__invd();
break;
}
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case VMX_EXIT_REASON_EXECUTE_VMWRITE:
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case VMX_EXIT_REASON_EXECUTE_VMREAD:
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case VMX_EXIT_REASON_EXECUTE_VMPTRST:
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case VMX_EXIT_REASON_EXECUTE_VMPTRLD:
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case VMX_EXIT_REASON_EXECUTE_VMCLEAR:
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case VMX_EXIT_REASON_EXECUTE_VMXOFF:
case VMX_EXIT_REASON_EXECUTE_VMXON:
case VMX_EXIT_REASON_EXECUTE_VMCALL:
{
vmentry_interrupt_information interrupt{};
interrupt.flags = interruption_type::hardware_exception;
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interrupt.vector = EXCEPTION_INVALID_OPCODE;
interrupt.valid = true;
__vmx_vmwrite(VMCS_CTRL_VMENTRY_INTERRUPTION_INFORMATION_FIELD, interrupt.flags);
return; // dont advance rip...
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}
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default:
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// TODO: check out the vmexit reason and add support for it...
__debugbreak();
break;
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}
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size_t rip, exec_len;
__vmx_vmread(VMCS_GUEST_RIP, &rip);
__vmx_vmread(VMCS_VMEXIT_INSTRUCTION_LENGTH, &exec_len);
__vmx_vmwrite(VMCS_GUEST_RIP, rip + exec_len);
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}