学习了，谢谢！

You can compare the test result with CPU-z under OS. BIOS may be return an error result as this Protocol is not an important one.

And if you just want to get the number of CPU cores, you may study the usage of CPUID.

I did something wrong since it say 8 cores.
On some generation of HP laptops there is a problem with some OS, doesn’t detect right all cores and complain about LAPIC,So I try to investigate what’s the problem not all cores enabled by BIOS or LAPIC doesn’t configured properly.
Here is what I did

#include
#include
#include
#include
#include

EFI_GUID gFrameworkEfiMpServiceProtocolGuid = { 0xf33261e7, 0x23cb, 0x11d5,
{ 0xbd, 0x5c, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 }};

extern EFI_BOOT_SERVICES *gBS;

int
EFIAPI
main (
IN int Argc,
IN CHAR16 **Argv
)
{
EFI_STATUS Status;
FRAMEWORK_EFI_MP_SERVICES_PROTOCOL *MP=NULL;
UINTN i;
UINTN NumberOfCPUs;
UINTN NumberOfEnabledCPUs;
UINTN BufferLenght;
UINTN MaximumNumberOfCPUs;
UINTN RendezvousIntNumber;
UINTN RendezvousProcLength;
EFI_MP_PROC_CONTEXT ProcessorContextBuffer;

//Get MP_Service Protocol
Status = gBS->LocateProtocol (&gFrameworkEfiMpServiceProtocolGuid, NULL, (VOID**)&MP);
if (EFI_ERROR (Status)) {
Print(L”Unable to initialize MP protocol interface!”);
return EFI_UNSUPPORTED;
}

// Determine number of processors
Status = MP->GetGeneralMPInfo( MP, &NumberOfCPUs , &MaximumNumberOfCPUs , &NumberOfEnabledCPUs , &RendezvousIntNumber , &RendezvousProcLength );

if (EFI_ERROR (Status))
{
Print( L”MP->GetNumEnabledProcessors:Unable to determine number of processors\n”) ;
return EFI_UNSUPPORTED;
}
Print(L”Number of Processors %d\n”,NumberOfCPUs);
Print(L”Max number of Processors %d\n”,MaximumNumberOfCPUs);
Print(L”Number of Enabled Processors %d\n”,NumberOfEnabledCPUs);
Print(L”RendezvousIntNumber %d\n”,RendezvousIntNumber);
Print(L”RendezvousProcLength %d\n”,RendezvousProcLength);

//Get more information by GetProcessorContext
for (i=0;iGetProcessorContext(MP, i , &BufferLenght , &ProcessorContextBuffer);

Print( L”Processor #%d ACPI Apic ID = %lX, Enabled = %x, Designation = %x, Health = %x, PackageNumber = %x, NumberOfCores = %x, NumberOfThreads = %x, ProcessorPALCompatibilityFlags = %x, ProcessorTestMask = %x \n”,
i,
ProcessorContextBuffer.ApicID,
ProcessorContextBuffer.Enabled,
ProcessorContextBuffer.Designation,
ProcessorContextBuffer.Health,
ProcessorContextBuffer.PackageNumber,
ProcessorContextBuffer.NumberOfCores,
ProcessorContextBuffer.NumberOfThreads,
ProcessorContextBuffer.ProcessorPALCompatibilityFlags,
ProcessorContextBuffer.ProcessorTestMask);
}

return EFI_SUCCESS;
}

Hi,

My suggestion is to build with Windows + VS2015, eg: you can install a virtualbox under Ubuntu.
As EDK2 is developed with Windows Tools Chain, it would get errors when you switch to Linux enviroment.

And you can try latest release https://github.com/tianocore/edk2/releases/tag/edk2-stable202002 .
It may have better support for Linux.

Library error
error 4000: Instance of library class [LibC] is not found
in [/home/G62/src/edk2/MPTest1/MPTest1.inf] [X64]
-solved by adding “!include StdLib\StdLib.inc”

main error
/home/G62/src/edk2/MPTest1/MPTest1.c:14:1: error: second argument of ‘main’ should be ‘char **’ [-Werror=main]
main ( …

return EFI_UNSUPPORTED error
/home/G62/src/edk2/MdePkg/Include/Base.h:927:38: error: overflow in implicit constant conversion [-Werror=overflow]
#define ENCODE_ERROR(StatusCode) ((RETURN_STATUS)(MAX_BIT | (StatusCode)))
-quick fix replaced return EFI_UNSUPPORTED with return EFI_SUCCESS

谢谢哈，我补充上。