Re: [PATCH v2 0/3] Put AP into safe hlt-loop code on S3 path

[Laszlo Ersek <lersek@redhat.com>]

On 11/13/16 13:51, Fan, Jeff wrote:
> Laszlo,
> 
> Thanks your testing. It seems that there is still some unknown issue existing.
> 
> I suggest to push this serial of patches firstly, because they have
> big progress to solve the AP crashed issue in
> https://bugzilla.tianocore.org/show_bug.cgi?id=216.

Sounds good to me.

> I could submit another bug to handle "AP lost" issue.

I hope that Paolo can continue to help us with the KVM trace analysis.

> Thus, JIewen's
> or others' patches could be push as long as they have no additional
> issue except for "AP Lost:".

I haven't gotten around testing Jiewen's v3 series yet. I think it would
be best if I could test Jiewen's v3 after this v2 series of yours is
committed. I'll report back with results.

Thanks
Laszlo

> 
> I could follow up to fix "AP Lost" issue.
> 
> Thanks!
> Jeff
> 
> 
> -----Original Message-----
> From: Laszlo Ersek [mailto:lersek@redhat.com] 
> Sent: Saturday, November 12, 2016 3:49 AM
> To: Fan, Jeff
> Cc: edk2-devel@ml01.01.org; Yao, Jiewen; Paolo Bonzini
> Subject: Re: [edk2] [PATCH v2 0/3] Put AP into safe hlt-loop code on S3 path
> 
> On 11/11/16 06:45, Jeff Fan wrote:
>> On S3 path, we will wake up APs to restore CPU context in 
>> PiSmmCpuDxeSmm driver. In case, one NMI or SMI happens, APs may exit 
>> from hlt state and execute the instruction after HLT instruction.
>>
>> But APs are not running on safe code, it leads OVMF S3 boot unstable.
>>
>> https://bugzilla.tianocore.org/show_bug.cgi?id=216
>>
>> I tested real platform with 64bit DXE.
>>
>> v2:
>>   1. Make stack alignment per Laszlo's comment.
>>   2. Trim whitespace at end of end per Laszlo's comment.
>>   3. Update year mark in file header.
>>   4. Enhancement on InterlockedDecrement() per Paolo's comment.
>>
>> Jeff Fan (3):
>>   UefiCpuPkg/PiSmmCpuDxeSmm: Put AP into safe hlt-loop code on S3 path
>>   UefiCpuPkg/PiSmmCpuDxeSmm: Place AP to 32bit protected mode on S3 path
>>   UefiCpuPkg/PiSmmCpuDxeSmm: Decrease mNumberToFinish in AP safe code
>>
>>  UefiCpuPkg/PiSmmCpuDxeSmm/CpuS3.c             | 33 +++++++++++++-
>>  UefiCpuPkg/PiSmmCpuDxeSmm/Ia32/SmmFuncsArch.c | 29 +++++++++++-
>>  UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.h    | 15 +++++++
>>  UefiCpuPkg/PiSmmCpuDxeSmm/X64/SmmFuncsArch.c  | 63 
>> ++++++++++++++++++++++++++-
>>  4 files changed, 136 insertions(+), 4 deletions(-)
>>
> 
> Applied this locally to master (ffd6b0b1b65e) for testing. I tested the series with a suspend-resume loop -- not a busy loop, just manually. (So there was always one second or so between adjacent steps.)
> 
> No crashes or emulation failures, but the "AP going lost" issue remains present -- sometimes Linux cannot bring up one of the four VCPUs after resume.
> 
> In the Ia32 case, this "AP lost" symptom surfaced after the 6th resume.
> 
> In the Ia32X64 case, I experienced the symptom after the 89th resume.
> 
> Thanks
> Laszlo
>