x86cpuosdevamd-processorapic

Does AMD support x2APIC?

I'm a learner of OS, and trying to write a kernel.

I googled for "AMD x2APIC" and found out some of the information about EPYC 7002 series seems like to support it.

But I cannot find the relative documentation.

So I would like to ask if the recent AMD processors support it, and if yes, where I can find documentation.

Solution

  • Yes, the same as in Intel's CPUs.
    You use cpuid (CPUID_Fn00000001_ECX) to check for it

    CPUID_Fn00000001_ECX

    and the Core::X86::Msr::APIC_BAR MSR to enable it:

    Core::X86::Msr::APIC_BAR

    Just like you would with Intel's CPUs.

    The x2APIC specification is here.