Re: [PATCH 1/1] ArmPkg: SmbiosMiscDxe: Don't populate ExtendedBiosSize when size < 16MB

["Sami Mujawar" <sami.mujawar@arm.com>]

Hi Rebecca,

Thank you for this patch. These changes look good to me.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

On 04/10/2021 05:22 PM, Rebecca Cran wrote:
> According to the SMBIOS specification, the ExtendedBiosSize field should
> be zero when the BIOS size is less than 16MB:
>
> "Size (n) where 64K * (n+1) is the size of the
> physical device containing the BIOS, in
> bytes.
> FFh - size is 16MB or greater, see Extended
> BIOS ROM Size for actual size."
>
> Fix the code in MiscBiosVendorFunction.c to only populate the
> ExtendedBiosSize field if the BIOS size is greater than 16MB.
>
> Fix the code to correctly populate the ExtendedBiosSize field with the
> unit bits set to MB if the size is between 16MB and 16GB.
>
> Signed-off-by: Rebecca Cran <rebecca@nuviainc.com>
> ---
>   ArmPkg/Universal/Smbios/SmbiosMiscDxe/Type00/MiscBiosVendorFunction.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/ArmPkg/Universal/Smbios/SmbiosMiscDxe/Type00/MiscBiosVendorFunction.c b/ArmPkg/Universal/Smbios/SmbiosMiscDxe/Type00/MiscBiosVendorFunction.c
> index 5aea32521bd3..5679ebaac8a5 100644
> --- a/ArmPkg/Universal/Smbios/SmbiosMiscDxe/Type00/MiscBiosVendorFunction.c
> +++ b/ArmPkg/Universal/Smbios/SmbiosMiscDxe/Type00/MiscBiosVendorFunction.c
> @@ -240,11 +240,12 @@ SMBIOS_MISC_TABLE_FUNCTION (MiscBiosVendor)
>     SmbiosRecord->BiosSegment = (UINT16)(FixedPcdGet32 (PcdFdBaseAddress) / SIZE_64KB);
>     if (BiosPhysicalSize < SIZE_16MB) {
>       SmbiosRecord->BiosSize = Base2ToByteWith64KUnit (BiosPhysicalSize) - 1;
> -    SmbiosRecord->ExtendedBiosSize.Size = BiosPhysicalSize / SIZE_1MB;
> -    SmbiosRecord->ExtendedBiosSize.Unit = 0; // Size is in MB
>     } else {
>       SmbiosRecord->BiosSize = 0xFF;
> -    if (BiosPhysicalSize > 0x3FFF) {
> +    if (BiosPhysicalSize < SIZE_16GB) {
> +      SmbiosRecord->ExtendedBiosSize.Size = BiosPhysicalSize / SIZE_1MB;
> +      SmbiosRecord->ExtendedBiosSize.Unit = 0; // Size is in MB
> +    } else {
>         SmbiosRecord->ExtendedBiosSize.Size = BiosPhysicalSize / SIZE_1GB;
>         SmbiosRecord->ExtendedBiosSize.Unit = 1; // Size is in GB
>       }

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