Re: [GIT PULL] TPM DEVICE DRIVER: tpmdd-next-v6.18

[Jarkko Sakkinen]

On Sun, Oct 05, 2025 at 11:09:08AM -0700, Linus Torvalds wrote:
> On Sun, 5 Oct 2025 at 08:47, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote:
> >
> >      This pull request disables
> > TCG_TPM2_HMAC from the default configuration as it does not perform well
> > enough [1].
> >
> > [1] https://lore.kernel.org/linux-integrity/20250825203223.629515-1-jarkko@xxxxxxxxxx/
> 
> This link is entirely useless, and doesn't explain what the problem
> was and *why* TPM2_TCG_HMAC shouldn't be on by default.
> 
> I think a much better link is
> 
>    https://lore.kernel.org/linux-integrity/20250814162252.3504279-1-cfenn@xxxxxxxxxx/
> 
> which talks about the problems that TPM2_TCG_HMAC causes.
> 
> Which weren't just about "not performing well enough", but actually
> about how it breaks TPM entirely for some cases.

Fair enough. I'll also enumerate the issues, and also roadmap
to heal the feature.

> 
>               Linus

BR, Jarkko