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

[Paolo Bonzini <pbonzini@redhat.com>]

On 14/11/2016 09:17, Laszlo Ersek wrote:
> 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.

I will, but it will take a few days.  In the meanwhile it would be nice
if you could take a look at using SendSmiIpiAllExcludingSelf() to bridge
the difference between 0xb2 on QEMU and on real hardware.

Paolo

>> 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
>>