Re: [PATCH 2/3] tpm: ensure tpm is in known state at startup

["Jarkko Sakkinen" <jarkko@kernel.org>]

On Mon Feb 19, 2024 at 7:17 PM UTC, Daniel P. Smith wrote:
> On 2/1/24 17:33, Jarkko Sakkinen wrote:
> > On Wed Jan 31, 2024 at 7:08 PM EET, Daniel P. Smith wrote:
> >> When tis core initializes, it assumes all localities are closed. There
> >         ~~~~~~~~
> >         tpm_tis_core
> > 
> >> are cases when this may not be the case. This commit addresses this by
> >> ensuring all localities are closed before initializing begins.
> > 
> > Remove the last sentence and replace with this paragraph:
> > 
> > "Address this by ensuring all the localities are closed in the beginning
> > of tpm_tis_core_init(). There are environments, like Intel TXT, which
> > may leave a locality open. Close all localities to start from a known
> > state."
>
> okay.
>
> > BTW, why we should motivated to take this patch anyway?
>
> Without this change, in this scenario the driver is unnecessarily 
> thrashing the TPM with locality requests/relinquishes pairs for which 
> will never take effect and that the TPM must do state change tracking. 
> While I am confident that TPM chips are resilient to such abuse, I do 
> not think it would be good form to knowingly allow such behavior to occur.

This would a factor better motivation part for the commit. I can 
buy this argument instead the one right now, thanks :-)

BR, Jarkko