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

[Auger Eric <eric.auger@redhat.com>]

Hi Stefan,

On 6/5/20 5:25 PM, Stefan Berger wrote:
> On 6/5/20 5:35 AM, Auger Eric wrote:
>> Hi Stefan,
>>
>> On 6/2/20 6:17 PM, Stefan Berger wrote:
>>> On 6/2/20 12:13 PM, Auger Eric wrote:
>>>> Hi Stefan,
>>>>
>>>> On 6/2/20 3:39 PM, 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.
>>>> If I revert this patch I am getting TPM2_ST_SESSIONS on my end.
>>> Is firmware/BIOS active? There's no TPM2_ST_SESSIONS coming out of QEMU.
>> So it looks SeaBIOS is in use (bios-256k.bin loaded).
>>
>> I can see MMIO accesses to the TPM and the following commands are
>> observable:
>> tpm_emu_tpm_thread code=0x181 tag=0x8001 len=0xa
>> tpm_emu_tpm_thread code=0x144 tag=0x8001 len=0xc
>> tpm_emu_tpm_thread code=0x121 tag=0x8002 len=0x20
>> This last one causes the assert (TPM2_CC_HierarchyControl)
>>
>> I checked in Seabios and effectively tpm20_hierarchycontrol() tags the
>> TPM2_CC_HierarchyControl command with TPM2_ST_SESSIONS
>>
>> Due to our emulation, maybe tpm_set_failure() gets called, inducing
>> tpm20_hierarchycontrol() call.
>>
>> That being said, what do you recommend? Remove the assert, improve the
>> emulation, other?
> 
> So this is an ACPI test. What role does the firmware play for success of
> the test? If the test relies on the firmware showing some sort of
> expected result, then I would recommend only running this test with an
> attached swtpm, like we run some other tests. If we don't need the
> firmware to succeed then I would just get rid of the assert. Probably no
> other test we have implemented so far was running the firmware...
FWIU The goal of this test is to compare the acpi tables generated by
qemu against reference ones. I dont think we expect from the FW any
specific result but I would prefer Igor or Michael to confirm.

In that case, removing the assert() allows to compare the specific DSDT
and TPM2 tables and that's our expectation here I think.

Thanks

Eric
> 
> 
>    Stefan
> 
> 
>>
>> Thank you in advance
>>
>> Best Regards
>>
>> Eric
>>
>>>     Stefan
>>>
>>>
>>>
> 
>