Re: [tpmdd-devel] [PATCH v3 2/7] tpm: validate TPM 2.0 commands

[Ken Goldman]

On 3/20/2017 5:54 AM, Alexander.Steffen@xxxxxxxxxxxx wrote:
> There are a few special cases that need some thought though. For
> example, it is possible to use an upgrade to switch the TPM family
> from 1.2 to 2.0 (or vice versa). In this case it seems useful to let
> the kernel reinitialize the TPM driver, so it uses the correct
> timeouts for communication, activates the correct features (resource
> manager or not?), etc., without needing to reboot the system.

In practice, would a TPM upgrade from TPM 1.2 to TPM 2.0 even occur 
without a reboot?  Is it an important use case?

1 - It would leave the SHA-256 PCRs in the reset state.

2 - It's possible that this upgrade would also require a BIOS upgrade.