MSR_CSTAR
wrmsr(MSR_CSTAR, 0);
svm_setmsrbrw(vcpu, MSR_CSTAR);
msr_store[VCPU_HOST_REGS_CSTAR].vms_index = MSR_CSTAR;
msr_store[VCPU_REGS_CSTAR].vms_index = MSR_CSTAR;
vmx_setmsrbrw(vcpu, MSR_CSTAR);
case MSR_CSTAR: return "CSTAR";