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

["Yao, Jiewen" <jiewen.yao@intel.com>]

HI jeff
The patch looks good and I have one minor suggestion on below comment:

Allocate safe memory in ACPI NVS for AP to execute hlt loop on S3 path
==>
Allocate safe memory in ACPI NVS for AP to execute hlt loop in protected mode on S3 path

I recommend we add "in protected mode" statement for the reason to allocate below 4GiB memory.

With that comment update, reviewed-by: Jiewen.yao@intel.com

Thank you
Yao Jiewen


> -----Original Message-----
> From: Fan, Jeff
> Sent: Tuesday, November 15, 2016 8:50 AM
> To: Yao, Jiewen <jiewen.yao@intel.com>
> Subject: FW: [edk2] [PATCH v2 0/3] Put AP into safe hlt-loop code on S3 path
> 
> 
> 
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Jeff Fan
> Sent: Friday, November 11, 2016 1:46 PM
> To: edk2-devel@lists.01.org
> Subject: [edk2] [PATCH v2 0/3] Put AP into safe hlt-loop code on S3 path
> 
> 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(-)
> 
> --
> 2.9.3.windows.2
> 
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