[PATCH 1/3] tpm: Disable TCG_TPM2_HMAC by default

[Jarkko Sakkinen]

On Wed May 22, 2024 at 11:18 AM EEST, Vitor Soares wrote:
> On Tue, 2024-05-21 at 08:33 -0400, James Bottomley wrote:
> > On Tue, 2024-05-21 at 10:10 +0300, Jarkko Sakkinen wrote:
> > > This benchmark could be done in user space using /dev/tpm0.
> > 
> > Let's actually try that.  If you have the ibmtss installed, the command
> > to time primary key generation from userspace on your tpm is
> > 
> > time tsscreateprimary -hi n -ecc nistp256
> > 
> > 
> > And just for chuckles and grins, try it in the owner hierarchy as well
> > (sometimes slow TPMs cache this)
> > 
> > time tsscreateprimary -hi o -ecc nistp256
> > 
> > And if you have tpm2 tools, the above commands should be:
> > 
> > time tpm2_createprimary -C n -G ecc256
> > time tpm2_createprimary -C o -G ecc256
> > 
> > James
> > 
> > 
>
> Testing on an arm64 platform I get the following results.

OK, appreciate these results. I try to get mine this week, if I can
allocate some bandwidth but latest early next week. The Intel CPU
I'll be testing is Intel Celeron J4025:

https://www.intel.com/content/www/us/en/products/sku/197307/intel-celeron-processor-j4025-4m-cache-up-to-2-90-ghz/specifications.html

So if things work reasonably fast with this, then I think we can
enable the feature at least on X86_64 by default, and make it
opt-in for other arch's.

I sent already this patch but holding with PR up until rc1 is
out so that there is some window to act:

https://lore.kernel.org/linux-integrity/20240521130921.15028-1-jarkko@kernel.org/

If I need to send an updated patch ("default X86_64") and rip
transcrip from below results.

But to do that correctly I'd need to know at least:

1. What is the aarch64 platform you are using?
2. What kind of TPM you are using and how is it connect?

Obviously if I make this decision, I'll put you as "Reported-by".

>
> hmac disabled:
>   time modprobe tpm_tis_spi
>   real    0m2.776s
>   user    0m0.006s
>   sys     0m0.015s
>
>   time tpm2_createprimary -C n -G ecc256
>   real    0m0.686s
>   user    0m0.044s
>   sys     0m0.025s
>
>   time tpm2_createprimary -C o -G ecc256
>   real    0m0.638s
>   user    0m0.048s
>   sys     0m0.009s
>
>
> hmac enabled:
>   time modprobe tpm_tis_spi
>   real    8m5.840s
>   user    0m0.005s
>   sys     0m0.018s
>
>
>   time tpm2_createprimary -C n -G ecc256
>   real    5m27.678s
>   user    0m0.059s
>   sys     0m0.009s
>
>   (after first command)
>   real    0m0.395s
>   user    0m0.040s
>   sys     0m0.015s
>
>   time tpm2_createprimary -C o -G ecc256
>   real    0m0.418s
>   user    0m0.049s
>   sys     0m0.009s
>
> hmac enabled + patches applied
>   time modprobe tpm_tis_spi
>   real    8m6.663s
>   user    0m0.000s
>   sys     0m0.021s
>
>
>   time tpm2_createprimary -C n -G ecc256
>   real    7m24.662s
>   user    0m0.048s
>   sys     0m0.022s
>
>   (after first command)
>   real    0m0.395s
>   user    0m0.047s
>   sys     0m0.009s
>
>   time tpm2_createprimary -C o -G ecc256
>   real    0m0.404s
>   user    0m0.046s
>   sys     0m0.012s
>
>
> Regards,
> Vitor Soares

BR, Jarkko