Re: [PATCH] tpm: fix selftest failure regression

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Fri, 2018-02-16 at 10:17 -0800, James Bottomley wrote:
> On Fri, 2018-02-16 at 10:34 +0200, Jarkko Sakkinen wrote:
> > 
> > Hi
> > 
> > See the comments below and please include this as a prequel patch
> > for the next version:
> > 
> > https://patchwork.kernel.org/patch/10208965/
> 
> Actually, I've got another curious bit of behaviour from my Nuvoton:
>  After an experiment with primary EK generation that sent it into
> failure mode (connected with something else, nothing to do with
> this), it's taken to returning 232 (TPM_RC_COMMAND_CODE) to a partial
> self test periodically on boot.  According to the manual this is
> impossible, so I think it's something to do with
> tpm_validate_command.  I think, perhaps, we shouldn't call the
> getcaps for the command codes until the self test is over, but I need
> to do more debugging to track down what's going on.
> 
> I've also got other reports of TPM_RC_COMMAND_CODE failures during
> self test, so this isn't just my screwed up chip.

This isn't anything to do with us synthesizing TPM_RC_COMMAND_CODE, the
status is definitely coming from the chip.  If I run a full self test
immediately after this, everything works as normal.  My instinct from
this is to take any return from the partial self tests except
TPM_RC_SUCCESS, TPM_RC_TESTING or TPM_RC_FAILURE as an indication we
should run a full self test, so I'll code that up.

Can anyone from the manufacturers shed any light on the
TPM_RC_COMMAND_CODE return from a partial self test?

James