Re: [Patch v3 4/5] UefiCpuPkg/CpuS3DataDxe: Remove below 4G limitation.

[Laszlo Ersek <lersek@redhat.com>]

On 08/10/18 06:19, Eric Dong wrote:
> Because PrepareApStartupVector() stores StackAddress to
> "mExchangeInfo->StackStart" (which has type (VOID*)), and because
> "UefiCpuPkg/PiSmmCpuDxeSmm/X64/MpFuncs.nasm" reads the latter with:
> 
>          add  edi, StackStartAddressLocation
>          add  rax, qword [edi]
>          mov  rsp, rax
>          mov  qword [edi], rax
> 
> in long-mode code. So code can remove below 4G limitation.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> ---
>  UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c b/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
> index 5b99a6e759..d18f33a5b8 100644
> --- a/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
> +++ b/UefiCpuPkg/CpuS3DataDxe/CpuS3Data.c
> @@ -46,9 +46,7 @@ typedef struct {
>  } ACPI_CPU_DATA_EX;
>  
>  /**
> -  Allocate EfiACPIMemoryNVS below 4G memory address.
> -
> -  This function allocates EfiACPIMemoryNVS below 4G memory address.
> +  Allocate EfiACPIMemoryNVS memory.
>  
>    @param[in] Size   Size of memory to allocate.
>  
> @@ -56,7 +54,7 @@ typedef struct {
>  
>  **/
>  VOID *
> -AllocateAcpiNvsMemoryBelow4G (
> +AllocateAcpiNvsMemory (
>    IN UINTN  Size
>    )
>  {
> @@ -64,9 +62,8 @@ AllocateAcpiNvsMemoryBelow4G (
>    EFI_STATUS            Status;
>    VOID                  *Buffer;
>  
> -  Address = BASE_4GB - 1;
>    Status  = gBS->AllocatePages (
> -                   AllocateMaxAddress,
> +                   AllocateAnyPages,
>                     EfiACPIMemoryNVS,
>                     EFI_SIZE_TO_PAGES (Size),
>                     &Address
> @@ -239,9 +236,13 @@ CpuS3DataInitialize (
>    AcpiCpuData->MtrrTable    = (EFI_PHYSICAL_ADDRESS)(UINTN)&AcpiCpuDataEx->MtrrTable;
>  
>    //
> -  // Allocate stack space for all CPUs
> +  // Allocate stack space for all CPUs.
> +  // Use ACPI NVS memory type because this data will be directly used by APs
> +  // in S3 resume phase in long mode. Also during S3 resume, the stack buffer
> +  // will only be used as scratch space. i.e. we won't read anything from it
> +  // before we write to it, in PiSmmCpuDxeSemm.

Please fix the typo: "PiSmmCpuDxeSemm" --> "PiSmmCpuDxeSmm".

With that:

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo

>    //
> -  Stack = AllocateAcpiNvsMemoryBelow4G (NumberOfCpus * AcpiCpuData->StackSize);
> +  Stack = AllocateAcpiNvsMemory (NumberOfCpus * AcpiCpuData->StackSize);
>    ASSERT (Stack != NULL);
>    AcpiCpuData->StackAddress = (EFI_PHYSICAL_ADDRESS)(UINTN)Stack;
>  
>