Re: [PATCH] UefiCpuPkg/MpInitLib: AP uses memory preceding IDT to store CpuMpData

[Laszlo Ersek <lersek@redhat.com>]

On 06/25/18 18:01, Laszlo Ersek wrote:
> Hello Ray,
> 
> On 06/25/18 04:54, Ruiyu Ni wrote:
>> Today's MpInitLib PEI implementation directly calls
>> PeiServices->GetHobList() from AP which may cause racing issue.
>>
>> This patch fixes this issue by storing the CpuMpData to memory
>> preceding IDT. Pointer to PeiServices pointer is stored there,
>> so after AP procedure returns, the PeiServices pointer should be
>> restored.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
>> Cc: Jeff Fan <vanjeff_919@hotmail.com>
>> Cc: Eric Dong <eric.dong@intel.com>
>> Cc: Jiewen Yao <jiewen.yao@intel.com>
>> Cc: Fish Andrew <afish@apple.com>
>> ---
>>  UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 33 ++++++++++++++++++-
>>  UefiCpuPkg/Library/MpInitLib/MpLib.c    |  8 +++++
>>  UefiCpuPkg/Library/MpInitLib/MpLib.h    | 27 +++++++++++++++-
>>  UefiCpuPkg/Library/MpInitLib/PeiMpLib.c | 56 +++++++++++++++++++++++++++++++--
>>  4 files changed, 119 insertions(+), 5 deletions(-)
>>
>> diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>> index e7ed21c6cd..26fead2c66 100644
>> --- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
>> +++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
> 
> [snip]
> 
>> +/**
>> +  Pop the CpuMpData.
>> +
>> +  @param[in] Pointer  The pointer value which was stored in where the CPU MP Data is pushed.
>> +  @param[in] Context  The context of push/pop operation.
>> +**/
>> +VOID
>> +PopCpuMpData (
>> +  IN VOID           *Pointer,
>> +  IN VOID           *Context
>> +  )
>> +{
> 
> (1) When I applied this patch for regression-testing, "git am"
> complained that the above line added two trailing space characters. Can
> you please remove them?
> 
> (2) Other than that, I tested this patch with OVMF -- the patch breaks
> OVMF. The last part of the log is:
> 
>> Loading PEIM [CpuMpPei]
>> Loading PEIM at 0x000BFE81000 EntryPoint=0x000BFE86DC6 CpuMpPei.efi
>> AP Loop Mode is 1
>> WakeupBufferStart = 9F000, WakeupBufferSize = 1000
>> TimedWaitForApFinish: reached FinishedApLimit=7 in 121 microseconds
>> APIC MODE is 1
>> MpInitLib: Find 8 processors in system.
>> Does not find any stored CPU BIST information from PPI!
>>   APICID - 0x00000000, BIST - 0x00000000
>>   APICID - 0x00000001, BIST - 0x00000000
>>   APICID - 0x00000002, BIST - 0x00000000
>>   APICID - 0x00000003, BIST - 0x00000000
>>   APICID - 0x00000004, BIST - 0x00000000
>>   APICID - 0x00000005, BIST - 0x00000000
>>   APICID - 0x00000006, BIST - 0x00000000
>>   APICID - 0x00000007, BIST - 0x00000000
>> Install PPI: [EfiSecPlatformInformation2Ppi]
>> Install PPI: [EfiPeiMpServicesPpi]
>> Notify: PPI Guid: [EfiPeiMpServicesPpi], Peim notify entry point: 8524F8
>> PlatformPei: OnMpServicesAvailable

Sorry, I failed to mention: after the last line is printed, the boot
process is stuck, and all CPUs appear spinning.

Thanks
Laszlo

> The last line is printed by OvmfPkg/PlatformPei, in
> "OvmfPkg/PlatformPei/FeatureControl.c". OVMF uses
> EFI_PEI_MP_SERVICES_PPI to write the Feature Control MSR on all CPUs.
> 
> https://github.com/tianocore/tianocore.github.io/wiki/Testing-SMM-with-QEMU,-KVM-and-libvirt#enable-nested-virtualization
> https://github.com/tianocore/tianocore.github.io/wiki/Testing-SMM-with-QEMU,-KVM-and-libvirt#confirm-simple-multiprocessing-during-boot
> 
> Thanks,
> Laszlo
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