Re: [PATCH 1/3 RESEND] tpm: add longer timeouts for creation commands.

From: Jarkko Sakkinen
Date: Mon Mar 05 2018 - 07:56:55 EST


On Sun, Mar 04, 2018 at 02:12:03PM +0200, Tomas Winkler wrote:
> TPM2_CC_Create(0x153) and TPM2_CC_CreatePrimary (0x131) involve generation
> of crypto keys which can be a computationally intensive task.
> The timeout is set to 3min.
>
> Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>

Where is the cover letter? Please send separate patches if they are
unrelated *or* add a cover letter that describes what they do as a
whole.

I will not review the next version if it does not have cover letter
describing the high level change and containing the change log.

> ---
> drivers/char/tpm/tpm-interface.c | 4 ++++
> drivers/char/tpm/tpm.h | 27 ++++++++++++++++-----------
> drivers/char/tpm/tpm2-cmd.c | 8 +++++---
> 3 files changed, 25 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 85bdfa8c3348..c0aa9d11ec7a 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -699,6 +699,10 @@ int tpm_get_timeouts(struct tpm_chip *chip)
> msecs_to_jiffies(TPM2_DURATION_MEDIUM);
> chip->duration[TPM_LONG] =
> msecs_to_jiffies(TPM2_DURATION_LONG);
> + chip->duration[TPM_LONG_LONG] =
> + msecs_to_jiffies(TPM2_DURATION_LONG_LONG);
> + chip->duration[TPM_UNDEFINED] =
> + msecs_to_jiffies(TPM2_DURATION_DEFAULT);
>
> chip->flags |= TPM_CHIP_FLAG_HAVE_TIMEOUTS;
> return 0;
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index f895fba4e20d..192ba68b39c2 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -67,7 +67,9 @@ enum tpm_duration {
> TPM_SHORT = 0,
> TPM_MEDIUM = 1,
> TPM_LONG = 2,
> - TPM_UNDEFINED,
> + TPM_LONG_LONG = 3,
> + TPM_UNDEFINED = 4,
> + TPM_DURATION_MAX,

This is starting to rotten to become unmaintainable.

Here is what I suggest to move forward:

* Have essentially two duration types:
1. Default
2. Long
'default' is the old long duration i.e. two seconds. 'long' is a

We should probably have two durations:

enum tpm_duration {
TPM_DURATION_DEFAULT = 2000,
TPM_DURATION_LONG = 300000,
};

These would be both for TPM 1.2 and TPM 2.0. Instead of having
table for every ordinal there should be a small tables describing
commands that require long timeout.

> - duration = 2 * 60 * HZ;
> + duration = msecs_to_jiffies(TPM2_DURATION_DEFAULT);

NAK for this change.

/Jarkko