Re: [PATCH 3/3] tpm: ibmvtpm: Add support for TPM 2

[Stefan Berger]

On 2/13/20 1:35 PM, Jason Gunthorpe wrote:
> On Thu, Feb 13, 2020 at 01:20:12PM -0500, Stefan Berger wrote:
>
> > I don't want side effects for the TPM 1.2 case here, so I am only modifying
> > the flag for the case where the new TPM 2 is being used. Here's the code
> > where it shows the effect.
> I'm surprised this driver is using AUTO_STARTUP, it was intended for
> embedded cases where their is no firmware to boot the TPM.


The TIS is also using it on any device.

static const struct tpm_class_ops tpm_tis = {
ÂÂÂ .flags = TPM_OPS_AUTO_STARTUP,
ÂÂÂ .status = tpm_tis_status,

https://elixir.bootlin.com/linux/latest/source/drivers/char/tpm/tpm_tis_core.c#L917


> Chips using AUTO_STARTUP are basically useless for PCRs/etc.
>
> I'd expect somthing called vtpm to have been started and PCRs working
> before Linux is started??

Yes, there's supposed to be firmware.

I only see one caller to tpm2_get_cc_attrs_tbl(chip), which is necessary 
to call. This caller happens to be in tpm2_auto_startup.


ÂÂ Stefan


> Jason