[PATCH] acpi: Set TPM2 LAML to actual log area size

[PATCH] acpi: Set TPM2 LAML to actual log area size

[Tu Dinh]

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.

Signed-off-by: Tu Dinh <ngoc-tu.dinh@vates.tech>
---
 tools/libacpi/build.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/libacpi/build.c b/tools/libacpi/build.c
index 2f29863db1..95188e217e 100644
--- a/tools/libacpi/build.c
+++ b/tools/libacpi/build.c
@@ -473,7 +473,7 @@ static int construct_secondary_tables(struct acpi_ctxt *ctxt,
             tpm2->platform_class = TPM2_ACPI_CLASS_CLIENT;
             tpm2->control_area_address = TPM_CRB_CTRL_REQ;
             tpm2->start_method = TPM2_START_METHOD_CRB;
-            tpm2->log_area_minimum_length = TPM_LOG_AREA_MINIMUM_SIZE;
+            tpm2->log_area_minimum_length = TPM_LOG_SIZE;
             tpm2->log_area_start_address = TPM_LOG_AREA_ADDRESS;
 
             set_checksum(tpm2,
-- 
2.43.0



--
Ngoc Tu Dinh | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech

Re: [PATCH] acpi: Set TPM2 LAML to actual log area size

[Andrew Cooper]

On 04/11/2025 4:12 pm, 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.
>
> Signed-off-by: Tu Dinh <ngoc-tu.dinh@vates.tech>
> ---
>  tools/libacpi/build.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/libacpi/build.c b/tools/libacpi/build.c
> index 2f29863db1..95188e217e 100644
> --- a/tools/libacpi/build.c
> +++ b/tools/libacpi/build.c
> @@ -473,7 +473,7 @@ static int construct_secondary_tables(struct acpi_ctxt *ctxt,
>              tpm2->platform_class = TPM2_ACPI_CLASS_CLIENT;
>              tpm2->control_area_address = TPM_CRB_CTRL_REQ;
>              tpm2->start_method = TPM2_START_METHOD_CRB;
> -            tpm2->log_area_minimum_length = TPM_LOG_AREA_MINIMUM_SIZE;
> +            tpm2->log_area_minimum_length = TPM_LOG_SIZE;

These happen to be the same number, but in making this change
TPM_LOG_AREA_MINIMUM_SIZE becomes unused.

I suggest we delete the constant while at it.  I don't think anything
good can come from having two of them.

Also, as it's no functional change, this is content for 4.22 I presume?

~Andrew

Re: [PATCH] acpi: Set TPM2 LAML to actual log area size

[Tu Dinh]

On 04/11/2025 18:11, Andrew Cooper wrote:
> On 04/11/2025 4:12 pm, 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.
>>
>> Signed-off-by: Tu Dinh <ngoc-tu.dinh@vates.tech>
>> ---
>>   tools/libacpi/build.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/libacpi/build.c b/tools/libacpi/build.c
>> index 2f29863db1..95188e217e 100644
>> --- a/tools/libacpi/build.c
>> +++ b/tools/libacpi/build.c
>> @@ -473,7 +473,7 @@ static int construct_secondary_tables(struct acpi_ctxt *ctxt,
>>               tpm2->platform_class = TPM2_ACPI_CLASS_CLIENT;
>>               tpm2->control_area_address = TPM_CRB_CTRL_REQ;
>>               tpm2->start_method = TPM2_START_METHOD_CRB;
>> -            tpm2->log_area_minimum_length = TPM_LOG_AREA_MINIMUM_SIZE;
>> +            tpm2->log_area_minimum_length = TPM_LOG_SIZE;
>
> These happen to be the same number, but in making this change
> TPM_LOG_AREA_MINIMUM_SIZE becomes unused.
>
> I suggest we delete the constant while at it.  I don't think anything
> good can come from having two of them.

Agreed.

>
> Also, as it's no functional change, this is content for 4.22 I presume?
Yes, it's for 4.22.

>
> ~Andrew
>



--
Ngoc Tu Dinh | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech