Hello, I am writing a code with intel vmx architecture(for vm purpose),here are my troubles: I use asm and cpp to write my code, for convinient purpose, I writethis code to call by cpp: __VMWRITE64_ proc Field:qword,pData:qword push r10 mov r10,qword ptr[rdx] xor rax,rax mov eax,ecx VMWRITE rax,r10 pop r10 jc error jz error jmp endok error: xor rax,rax ret endok: mov rax,1 ret __VMWRITE64_ endp and this is the caller: re = __VMWRITE64(VMX_VMCS16_HOST_FIELD_CS, (u64*)&cs); that code sometimes works well,but sometimes it cause BSOD on my Windows 7 X64, the CS selector of my OS is always 0x10,I am frustrated, because that BSOD do not have anyregular patterns.My cpu is core i3 2100 ,could you help me? Thanks.