Re: WSMT bits

["Laszlo Ersek" <lersek@redhat.com>]

On 03/11/20 13:00, Yao, Jiewen wrote:
> Great question on ACPIReclaim!
> Yes, it is the confusing part.
> 
> 1) Per ACPI specification, ACPI reclaim is the memory to hold the ACPI table.
> It *may* be reclaimed by OS as OS memory, after OS copied the ACPI table to its own local space.
> As such, we need make sure it is treated as *OS usable* memory. So we do not allow SMM driver to touch it.
> 
> 2) Per our experience, ACPI reclaim *may* be treated as reserved memory by some OS.
> OS just does not use it.
> As such, we need group them in the BIN to not leave too many holes for OS. So we need track it in MemoryTypeInfo.
> 
> 
> You may refer to https://github.com/tianocore/edk2-platforms/blob/master/Platform/Intel/MinPlatformPkg/PlatformInit/PlatformInitPei/PlatformInitPreMem.c
> Below is our platform template.
> GLOBAL_REMOVE_IF_UNREFERENCED EFI_MEMORY_TYPE_INFORMATION mDefaultMemoryTypeInformation[] = {
>   { EfiACPIReclaimMemory,   FixedPcdGet32 (PcdPlatformEfiAcpiReclaimMemorySize) },  // ASL
>   { EfiACPIMemoryNVS,       FixedPcdGet32 (PcdPlatformEfiAcpiNvsMemorySize) },      // ACPI NVS (including S3 related)
>   { EfiReservedMemoryType,  FixedPcdGet32 (PcdPlatformEfiReservedMemorySize) },     // BIOS Reserved (including S3 related)
>   { EfiRuntimeServicesData, FixedPcdGet32 (PcdPlatformEfiRtDataMemorySize) },       // Runtime Service Data
>   { EfiRuntimeServicesCode, FixedPcdGet32 (PcdPlatformEfiRtCodeMemorySize) },       // Runtime Service Code
>   { EfiMaxMemoryType, 0 }
> };

Very tricky indeed. Thanks for the explanation! Now I know what to do.

Cheers!
Laszlo