Re: [PATCH v3] tpm: tis: Double the timeout B to 4s

[Jarkko Sakkinen <jarkko@kernel.org>]

On Fri, Apr 04, 2025 at 10:23:14AM +0200, Michal Suchanek wrote:
> With some Infineon chips the timeouts in tpm_tis_send_data (both B and
> C) can reach up to about 2250 ms.
> 
> Timeout C is retried since
> commit de9e33df7762 ("tpm, tpm_tis: Workaround failed command reception on Infineon devices")
> 
> Timeout B still needs to be extended.
> 
> The problem is most commonly encountered with context related operation
> such as load context/save context. These are issued directly by the
> kernel, and there is no retry logic for them.
> 
> When a filesystem is set up to use the TPM for unlocking the boot fails,
> and restarting the userspace service is ineffective. This is likely
> because ignoring a load context/save context result puts the real TPM
> state and the TPM state expected by the kernel out of sync.
> 
> Chips known to be affected:
> tpm_tis IFX1522:00: 2.0 TPM (device-id 0x1D, rev-id 54)
> Description: SLB9672
> Firmware Revision: 15.22
> 
> tpm_tis MSFT0101:00: 2.0 TPM (device-id 0x1B, rev-id 22)
> Firmware Revision: 7.83
> 
> tpm_tis MSFT0101:00: 2.0 TPM (device-id 0x1A, rev-id 16)
> Firmware Revision: 5.63
> 
> Link: https://lore.kernel.org/linux-integrity/Z5pI07m0Muapyu9w@kitsune.suse.cz/
> Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> ---
> v2: Only extend timeout B
> v3: Update commit message
> ---
>  drivers/char/tpm/tpm_tis_core.h | 2 +-
>  include/linux/tpm.h             | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 970d02c337c7..6c3aa480396b 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -54,7 +54,7 @@ enum tis_int_flags {
>  enum tis_defaults {
>  	TIS_MEM_LEN = 0x5000,
>  	TIS_SHORT_TIMEOUT = 750,	/* ms */
> -	TIS_LONG_TIMEOUT = 2000,	/* 2 sec */
> +	TIS_LONG_TIMEOUT = 4000,	/* 4 secs */
>  	TIS_TIMEOUT_MIN_ATML = 14700,	/* usecs */
>  	TIS_TIMEOUT_MAX_ATML = 15000,	/* usecs */
>  };
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 6c3125300c00..3db0b6a87d45 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -224,7 +224,7 @@ enum tpm2_const {
>  
>  enum tpm2_timeouts {
>  	TPM2_TIMEOUT_A          =    750,
> -	TPM2_TIMEOUT_B          =   2000,
> +	TPM2_TIMEOUT_B          =   4000,
>  	TPM2_TIMEOUT_C          =    200,
>  	TPM2_TIMEOUT_D          =     30,
>  	TPM2_DURATION_SHORT     =     20,
> -- 
> 2.47.1
> 
> 

Cc: stable@vger.kernel.org # v6.1+

Probably best that I'll piggyback a patch set for stable with the two
fixes, in order to cause least noise. I need to do this *after* an
ack'd PR to -rc2.

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko