Re: [Qemu-devel] [PATCH v9 6/6] tpm: add ACPI memory clear interface

[Stefan Berger]

On 08/14/2018 06:02 AM, Marc-André Lureau wrote:
> > > --- a/docs/specs/tpm.txt
> > > +++ b/docs/specs/tpm.txt
> > > @@ -121,6 +121,8 @@ layout:
> > >    +----------+--------+--------+-------------------------------------------+
> > >    | next_step|   0x1  |  0x159 | Operation to execute after reboot by      |
> > >    |          |        |        | firmware. Used by firmware.               |
> > > + +----------+--------+--------+-------------------------------------------+
> > > + | movv     |   0x1  |  0x200 | Memory overwrite variable                 |
> > >    +----------+--------+--------+-------------------------------------------+
> > why 0x200 and not 0x15a ?
> I thought it would be better to leave some room for PPI, but that
> probably doesn't help much. Let's move it to 0x15a.
>
> > Btw why TPM_PPI_ADDR_SIZE is 0x400 and excess bytes aren't documented anywhere?
> I guess for the same reason, Stefan wanted to have some room for
> future changes. Is that a problem?
>
> Stefan, can you confirm?
Yes, this was the primary reason.

   Stefan