Re: [RFC 4/6] tests: tpm-emu: Remove assert on TPM2_ST_NO_SESSIONS

[Stefan Berger]

On 6/2/20 9:39 AM, Stefan Berger wrote:
> On 6/1/20 6:21 AM, Eric Auger wrote:
> > While writing tests for checking the content of TPM2 and DSDT
> > along with TPM-TIS instantiation I attempted to reuse the
> > framework used for TPM-TIS tests. However While dumping the
> > ACPI tables I get an assert on TPM2_ST_NO_SESSIONS. My assumption
> > is maybe the other tests did not execute long enough to encounter
> > this. So I tentatively propose to remove the assert as it
> > does not seem to break other tests and enable the new ones.
> >
> > Signed-off-by: Eric Auger <eric.auger@redhat.com>
> > ---
> >   tests/qtest/tpm-emu.c | 1 -
> >   1 file changed, 1 deletion(-)
> >
> > diff --git a/tests/qtest/tpm-emu.c b/tests/qtest/tpm-emu.c
> > index c43ac4aef8..298d0eec74 100644
> > --- a/tests/qtest/tpm-emu.c
> > +++ b/tests/qtest/tpm-emu.c
> > @@ -49,7 +49,6 @@ static void *tpm_emu_tpm_thread(void *data)
> >           s->tpm_msg->tag = be16_to_cpu(s->tpm_msg->tag);
> >           s->tpm_msg->len = be32_to_cpu(s->tpm_msg->len);
> >           g_assert_cmpint(s->tpm_msg->len, >=, minhlen);
> > -        g_assert_cmpint(s->tpm_msg->tag, ==, TPM2_ST_NO_SESSIONS);
> You should not have to remove this. The tests are skipped if swtpm 
> does not support TPM 2 via --tpm2 option. This would be a very old 
> swtpm version, though. So, all tests are run with --tpm2 option and 
> any response received from the TPM would be a TPM 2 response that 
> should have TPM2_ST_NO_SESSIONS as the tag. I'd be curious what other 
> value you are seeing there.


In hw/tpm/tpm_util.c tpm_util_test_tpmdev() we have a probing function 
that tries to determine whether the attached TPM is a TPM 1.2 or TPM 2. 
It sends a TPM 2 command first and I would say this is the only command 
we should see in this (fake) TPM emulation here. We respond with a TPM 2 
command header [indicating failure], but the probing function should 
then not proceed to probe with the TPM 1.2 command.


> >             s->tpm_msg = g_realloc(s->tpm_msg, s->tpm_msg->len);
> >           qio_channel_read(ioc, (char *)&s->tpm_msg->code,