MSR_AMD_GSBASE
old = (uintptr_t)rdmsr(MSR_AMD_GSBASE);
wrmsr(MSR_AMD_GSBASE, (uint64_t)cpu);
wrmsr(MSR_AMD_GSBASE, (uint64_t)old);
printf(fmt, "fsb", rdmsr(MSR_AMD_FSBASE), "gsb", rdmsr(MSR_AMD_GSBASE),
wrmsr(MSR_AMD_GSBASE, (uint64_t)&cpus[0]);
movl $MSR_AMD_GSBASE, %ecx; \
case REG_GSBASE: return (rdmsr(MSR_AMD_GSBASE));
PANICNVADD(pnv, "gsbase", rdmsr(MSR_AMD_GSBASE));
wrmsr(MSR_AMD_GSBASE, (uint64_t)&cpus[0]);
wrmsr(MSR_AMD_GSBASE, kgsbase);
wrmsr(MSR_AMD_GSBASE, kgsbase);