Re: [PATCH for-4.22 v2] acpi: Set TPM2 LAML to actual log area size

["Tu Dinh" <ngoc-tu.dinh@vates.tech>]

On 06/11/2025 13:19, Jan Beulich wrote:
> On 06.11.2025 13:13, Tu Dinh wrote:
>> On 06/11/2025 13:10, Jan Beulich wrote:
>>> On 05.11.2025 01:03, Tu Dinh wrote:
>>>> The LAML field should follow the TCG PFP specification:
>>>>
>>>> The TCG ACPI specification uses the field name "Log Area Minimum
>>>> Length", but the field value is the actual log area length reserved by
>>>> Platform Firmware, not a lower bound.
>>>
>>> And this is said where? Even the field description (ACPI 6.5) reads "Identifies
>>> the minimum length (in bytes) of the system’s preboot CC event log area." (I
>>> agree it makes little sense that way, but the change still needs proper
>>> explanation.)
>>
>> The above is an exact quote from the "TCG PC Client Platform Firmware
>> Profile Specification Version 1.06 Revision 52".
>
> Interesting. It didn't become clear to me that this actually is a quotation.
> Perhaps:
>
> The LAML field should follow the TCG PC Client Platform Firmware Profile
> Specification Version. Version 1.06 Revision 52 says:
>
> 'The TCG ACPI specification uses the field name "Log Area Minimum
>   Length", but the field value is the actual log area length reserved by
>   Platform Firmware, not a lower bound.'
>
> Remove the now-unused TPM_LOG_AREA_MINIMUM_SIZE.
>
> ? Then
> Acked-by: Jan Beulich <jbeulich@suse.com>
> and I could make the adjustment while committing (after 4.21 was branched off,
> of course).
>
> Jan

That's clearer, thanks.


--
Ngoc Tu Dinh | Vates XCP-ng Developer

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