Re: [edk2-devel] [PATCH - resend] MdeModulePkg/Universal/SmbiosDxe: Scan for existing tables

["Patrick Rudolph" <patrick.rudolph@9elements.com>]

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.

Regards,
Patrick Rudolph

On Wed, Mar 3, 2021 at 9:13 AM Ni, Ray <ray.ni@intel.com> 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.
>
> > +ValidateSmbios20Table(
> > +ValidateSmbios30Table(
>
> 2. I will defer to experts (Dandan, Star and Zhichao) to review whether the above two functions are implemented properly.
>
> >
> > +ParseAndAddExistingSmbiosTable(
> > +  IN EFI_HANDLE                    ImageHandle,
> > +  IN SMBIOS_STRUCTURE_POINTER      Smbios,
> > +  IN UINTN                         Length
> > +) {
> > +  EFI_STATUS                    Status;
> > +  CHAR8                         *String;
> > +  EFI_SMBIOS_HANDLE             SmbiosHandle;
> > +  SMBIOS_STRUCTURE_POINTER      SmbiosEnd;
> > +
> > +  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-
> > >TableMaximumSize);
>
> 4. Should we copy from Smbios30Table->TableAddress instead of Smbios30Table?
>
> >
> > +    Status = ParseAndAddExistingSmbiosTable(ImageHandle, Smbios,
> > Smbios30Table->TableMaximumSize);
>
> 5. Can you explain in specific why SMBIOS table should be duplicated before parsing?
>
>