MSR_GSBASE
wrmsr(MSR_GSBASE, (u_int64_t)ci);
gsb = rdmsr(MSR_GSBASE);
(void *)rdmsr(MSR_GSBASE), (void *)rdmsr(MSR_KERNELGSBASE));
svm_setmsrbrw(vcpu, MSR_GSBASE);
vmx_setmsrbrw(vcpu, MSR_GSBASE);
case MSR_GSBASE: return "GSBASE";