Re: [PATCH v4 1/5] acpi: Convert build_tpm2() to build_append* API

[Igor Mammedov]

On Fri, 19 Jun 2020 07:19:51 -0400
Stefan Berger <stefanb@linux.ibm.com> wrote:

> On 6/19/20 5:43 AM, Auger Eric wrote:
> > Hi Laszlo,
> >
> > On 6/19/20 11:38 AM, Laszlo Ersek wrote:  
> >> On 06/18/20 09:50, Auger Eric wrote:  
> >>> Hi Stefan, Igor,
> >>>
> >>> On 6/16/20 4:11 PM, Stefan Berger wrote:  
> >>>> On 6/16/20 8:33 AM, Igor Mammedov wrote:  
> >>>>> nevertheless looks like faithfull conversion,
> >>>>> btw why you didn't drop Acpi20TPM2 structure definition?
> >>>>>  
> >>>> If we get rid of the table we should keep a reference to this document,
> >>>> table 7: "TCG ACPI Specification; Family 1.2 and 2.0; Level 00 Revision
> >>>> 00.37, December 19, 2014"
> >>>>
> >>>> https://trustedcomputinggroup.org/wp-content/uploads/TCG_ACPIGeneralSpecification_1-10_0-37-Published.pdf
> >>>>
> >>>>
> >>>>  
> >>> Further looking at this spec, the log_area_minimum_length and
> >>> log_area_start_address only are described in
> >>> - Table 2 (TCG Hardware InterfaceDescription Table Format for TPM 1.2
> >>> Clients)
> >>> - Table 4 (TCG Hardware Interface Description Table Format for TPM 1.2
> >>> Servers)
> >>> but not in Table 7, ie. not for TPM 2.0.
> >>>
> >>> Are they really needed for TPM2 or what do I miss?  
> >> (side comment:
> >>
> >> LASA and LAML are optional with TPM-2.0. From the discussion at
> >> <https://bugzilla.tianocore.org/show_bug.cgi?id=978>.  
> 
> 
> They are needed for (x86) BIOS, such as SeaBIOS, not for UEFI, though. I 
> do not know about ARM.
> 
> 
> > Thank you for the pointer and info. I failed to find this info in the
> > spec. Given the risk of confusion, I would personally keep struct
> > Acpi20TPM2 and maybe add a comment. Stefan?  
> 
> Either way is fine with me for as long as we know where to find the 
> layout of the structure.
I'd remove Acpi20TPM2 as it hardly documents anything, and add a comment
pointing to the concrete spec that has these fields.

TCGTCG ACPI SpecificationFamily “1.2” and “2.0”Version 1.2,Revision 8

> 
>    Stefan
> 
> >
> > Thanks
> >
> > Eric  
> >> )
> >>
> >> Thanks
> >> Laszlo
> >>  
>