[Fw_Os_Forum] Support for EFI MP Services

[Brett Stahlman]

Acan,
Can you point me to the GUID for the Framework MP Service Protocol? So
far, I've seen only this one:

#define EFI_MP_SERVICES_PPI_GUID \
{0xee16160a, 0xe8be, 0x47a6,\
{0x82, 0xa, 0xc6, 0x90, 0xd, 0xb0, 0x25, 0xa } }

Thanks,
Brett S.

On Sun, Jul 17, 2016 at 8:34 PM, Chen, Ming (Acan, DTD-SH)
<ming.chen at hp.com> wrote:
> Hi Brett,
>
> Just mention that there are two MP Service protocols: Framework MP Service Protocol, and (PI) MP Service Protocol.
> Note sure if you have tried both when you BS->LocateProtocol()?
>
>
> Thanks,
> Acan
>
> -----Original Message-----
> From: fw_os_forum-bounces at mailman.uefi.org [mailto:fw_os_forum-bounces at mailman.uefi.org] On Behalf Of Brett Stahlman
> Sent: Saturday, July 16, 2016 3:27 AM
> To: fw_os_forum at mailman.uefi.org
> Subject: Re: [Fw_Os_Forum] Support for EFI MP Services
>
> Aaron,
> So methods like GetNumberOfProcessors and StartupAllAPs (documented here http://www.uefi.org/sites/default/files/resources/Plugfest_Multiprocessing-with_UEFI-McDaniel.pdf)
> are not meant to be called from a boot loader using Boot Services?
>
> I will have a look at the other references. Hopefully the firmware's AP initialization obviates the need for some of the tedious, low-level real mode trampoline code I've seen in the kernel and other loader code performing AP bring up... If UEFI simplifies only the BSP side of things, it doesn't seem a very complete solution...
>
> Thanks,
> Brett S.
>
> On Fri, Jul 15, 2016 at 11:28 AM,  <Aaron.Pop at congatec.com> wrote:
>> Hi Brett,
>>
>>>>1. Is there a way to add support for MP Services to firmware that
>>>>doesn't  have it natively? Is there a list somewhere documenting
>>>>which firmware  supports?
>> If you platform doesn't support the MP services protocol, chances are
>> that your platform is not compliant with the Platform Initialization
>> specification.  Additionally, the PI specification defines protocols
>> that are intended for use by the firmware, not by boot loaders or the
>> OS. I would highly recommend that your boot loader only use protocols
>> that are defined in the UEFI specification.
>
>
>>
>>>>2. What is the best way to bring up the APs in an environment that
>>>>doesn't  support the MP Services Protocol? I've read something that
>>>>suggests it might  be easier with UEFI than with BIOS because the PI
>>>>firmware does some  pre-initialization of the APs even before handoff
>>>>to the BSP - but I haven't  found much documentation on this...
>> X86/X86_64 operating systems follow intel's multi processor
>> specification for waking APs when they are given control.
>> (http://download.intel.com/design/archives/processors/pro/docs/2420160
>> 6.pdf) All firmware (even legacy BIOSes) would initialize all
>> processors in the system, and then would either halt the APs, or put
>> the APs into a spin loop and only leave the BSP (boot strap processor)
>> running when giving control to a bootloader.
>>
>> For more information, you can refer to
>> http://wiki.osdev.org/Symmetric_Multiprocessing, or you can check out
>> how the linux kernel performs multi processor bring up.
>>
>> -Aaron
>>
>>
>>
>>
>>
>>
>> From:        Brett Stahlman <brettstahlman at gmail.com>
>> To:        fw_os_forum at mailman.uefi.org
>> Date:        07/15/2016 09:11 AM
>> Subject:        [Fw_Os_Forum] Support for EFI MP Services
>> Sent by:        fw_os_forum-bounces at mailman.uefi.org
>> ________________________________
>>
>>
>>
>> I'm working on an x86_64 UEFI boot loader that runs on the BSP in
>> 64-bit long mode, and must bring up APs (secondary processors) after
>> some preliminary initialization. I've seen some documentation on EFI
>> MP (multi-processor) Service Protocol, but the headers in gnu-efi
>> don't appear to support it, and BS->LocateProtocol() reports status 14
>> (EFI_NOT_FOUND). My questions are...
>>
>> 1. Is there a way to add support for MP Services to firmware that
>> doesn't have it natively? Is there a list somewhere documenting which
>> firmware supports?
>> 2. What is the best way to bring up the APs in an environment that
>> doesn't support the MP Services Protocol? I've read something that
>> suggests it might be easier with UEFI than with BIOS because the PI
>> firmware does some pre-initialization of the APs even before handoff
>> to the BSP - but I haven't found much documentation on this...
>>
>> Any help would be greatly appreciated.
>> Thanks,
>> Brett S.
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