Re: [tpmdd-devel] [PATCH RFC 2/2] tpm: refactor tpm2_get_tpm_pt to tpm2_getcap_cmd

[Jarkko Sakkinen]

On Thu, Nov 17, 2016 at 05:20:36PM +0530, Nayna wrote:
 
> I tested this for capability TPM2_CAP_PCRS. It seems TPM2_CAP_PCRS
> capability always returns full PCR allocation, and more_data as 0, So, I
> think the idea of looping over based on more_data may not work for this
> capability.

You can always request one value at a time until there's no more.

If you request N values, depending on the hardware, the hardware returns
to you anything from 1 to N values. If you implement a function that
requests N values in the command, you *must* handle the case where
moreData is 1 even if the hardware you are testing that never happens.

That's the reason why I would start with a function that you request one
property of one capability and optimize it in future if it doesn't scale
for some workload.

Do you have a workload where it doesn't scale?

/Jarkko