Re: [PATCH - resend] MdeModulePkg/Universal/SmbiosDxe: Scan for existing tables

Patrick Rudolph

Hi Ray,
thanks for your feedback.

Currently a single HOB containing all the SMBIOS table is exported by coreboot.
As coreboot doesn't support multiple HOBs with the same ID, #2 isn't a solution.

I'll look into passing a HOB instead of using
EfiGetSystemConfigurationTable and see if I can get rid of the table
shadow copy.

Patrick Rudolph

On Wed, Mar 3, 2021 at 9:13 AM Ni, Ray <> wrote:

In general, I agree this solution that lets SMBIOS driver directly absorbs the SMBIOS table from PEI.
This can eliminate the needs of a separate driver that consumes the HOB and calls SMBIOS protocol to add the SMBIOS structures.

There are two options for the HOB design:
1. A single HOB that points to the SMBIOS table.
2. Multiple HOBs that each points to a SMBIOS structure.

In my opinion, option #2 is more flexible because it doesn't require the bootloader to consolidate all the SMBIOS structures together.
The CPU module in the bootloader can produce the type 4 and 7 structures.
The PCI module in the bootloader can produce the type 9 structures.

But, I am not sure if option #2 is conflict with what coreboot does. Does coreboot produce the whole SMBIOS table in a single buffer?
Option #2 also doesn't care whether it's a SMBIOS 3.0 table or 2.x table.

+ Status = EfiGetSystemConfigurationTable (
1. Why don't you directly get the data from HOB list? This can eliminate the code in BlSupportDxe that gets data in HOB and publishes to
configuration table.

2. I will defer to experts (Dandan, Star and Zhichao) to review whether the above two functions are implemented properly.

+ IN EFI_HANDLE ImageHandle,
+ IN UINTN Length
+) {
+ EFI_STATUS Status;
+ CHAR8 *String;
+ SmbiosEnd.Raw = Smbios.Raw + Length;
+ do {
+ // Check for end marker
+ if (Smbios.Hdr->Type == 127) {
3. Please use SMBIOS_TYPE_END_OF_TABLE instead of hardcode 127.

+ CopyMem (Smbios.Raw, (VOID *)Smbios30Table, Smbios30Table-
4. Should we copy from Smbios30Table->TableAddress instead of Smbios30Table?

+ Status = ParseAndAddExistingSmbiosTable(ImageHandle, Smbios,
5. Can you explain in specific why SMBIOS table should be duplicated before parsing?

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