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Message-ID: <979629af-e224-4308-a9a1-c66a60003d2d@linux.ibm.com>
Date: Thu, 3 Oct 2024 18:25:14 -0400
From: Stefan Berger <stefanb@...ux.ibm.com>
To: Jonathan McDowell <noodles@...th.li>, linux-integrity@...r.kernel.org,
Jarkko Sakkinen <jarkko@...nel.org>,
James Bottomley <James.Bottomley@...senpartnership.com>
Cc: Peter Huewe <peterhuewe@....de>, Jason Gunthorpe <jgg@...pe.ca>,
linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH] tpm: Workaround failed command reception on Infineon
devices
On 10/3/24 5:59 PM, Stefan Berger wrote:
>
>
> On 10/2/24 1:04 PM, Jonathan McDowell wrote:
>> (I'm still in the process of testing this to confirm it fixes the
>> errata I've seen, but I wanted to send it out for comments to make sure
>> it's a reasonable approach.)
>>
>> Some Infineon devices have a issue where the status register will get
>> stuck with a quick REQUEST_USE / COMMAND_READY sequence. The work around
>
> Did you tell Infineon about it? Maybe they should have a look at their
> firmware.
>
> What are the TPMs in your fleet doing? I heared that some TPMs
> pre-create keys in the background once users requested a few. I would
> try to create a few primary keys with different combination of key flags
Actually make this child keys of primary keys:
> tsscreateprimary
Handle 80000000
> while :; do time tsscreate -hp 80000000 -si -opem pubkey.pem ; cat
pubkey.pem; done
This should give a different key every time and maybe key creation time
goes up at some point...
> set and in different hierarchies (and flush them) to use up these
> precreated keys and see whether that leads to any issues with the TIS
> responsiveness once presumably the device starts creating keys in the
> background...
>
>> is to retry the command submission. Add appropriate logic to do this in
>
> I would describe it as 'retrying to set the TPM_STS_COMMAND_READY flag
> on the TIS STS register' because you are not retring a (TPM) command
> submission, like resubmitting a TPM2_PCR_Extend for example.
>
>
>
>> the send path.
>>
>> Signed-off-by: Jonathan McDowell <noodles@...a.com>
>> ---
>> drivers/char/tpm/tpm_tis_core.c | 24 +++++++++++++++++++-----
>> drivers/char/tpm/tpm_tis_core.h | 1 +
>> include/linux/tpm.h | 1 +
>> 3 files changed, 21 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm_tis_core.c
>> b/drivers/char/tpm/tpm_tis_core.c
>> index f6aa0dfadb93..940abd1a868e 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -432,16 +432,27 @@ static int tpm_tis_recv(struct tpm_chip *chip,
>> u8 *buf, size_t count)
>> static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf,
>> size_t len)
>> {
>> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> - int rc, status, burstcnt;
>> + int rc, status, burstcnt, retry;
>> + bool status_fix = test_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags);
>
> This should probably be moved to the top.
> int retry = status_fix ? 3 : 1;
>
>> size_t count = 0;
>> bool itpm = test_bit(TPM_TIS_ITPM_WORKAROUND, &priv->flags);
>> status = tpm_tis_status(chip);
>> if ((status & TPM_STS_COMMAND_READY) == 0) {
>> - tpm_tis_ready(chip);
>> - if (wait_for_tpm_stat
>> - (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
>> - &priv->int_queue, false) < 0) {
>> + retry = status_fix ? 3 : 1;
>> +
>> + while (retry > 0) {
>> + tpm_tis_ready(chip);
>> + if (wait_for_tpm_stat
>> + (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
>> + &priv->int_queue, false) >= 0) {
>> + break;
>> + }
>> +
>> + retry--;
>> + }
>> +
>> + if (retry == 0) {
>> rc = -ETIME;
>> goto out_err;
>> }
>> @@ -1147,6 +1158,9 @@ int tpm_tis_core_init(struct device *dev, struct
>> tpm_tis_data *priv, int irq,
>> priv->timeout_max = TIS_TIMEOUT_MAX_ATML;
>> }
>> + if (priv->manufacturer_id == TPM_VID_IFX)
>> + set_bit(TPM_TIS_STATUS_WORKAROUND, &priv->flags);
>> +
>> if (is_bsw()) {
>> priv->ilb_base_addr = ioremap(INTEL_LEGACY_BLK_BASE_ADDR,
>> ILB_REMAP_SIZE);
>> diff --git a/drivers/char/tpm/tpm_tis_core.h
>> b/drivers/char/tpm/tpm_tis_core.h
>> index 13e99cf65efe..f888da57535d 100644
>> --- a/drivers/char/tpm/tpm_tis_core.h
>> +++ b/drivers/char/tpm/tpm_tis_core.h
>> @@ -89,6 +89,7 @@ enum tpm_tis_flags {
>> TPM_TIS_INVALID_STATUS = 1,
>> TPM_TIS_DEFAULT_CANCELLATION = 2,
>> TPM_TIS_IRQ_TESTED = 3,
>> + TPM_TIS_STATUS_WORKAROUND = 4,
>> };
>> struct tpm_tis_data {
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index 4ee9d13749ad..5f4998626a98 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -272,6 +272,7 @@ enum tpm2_cc_attrs {
>> #define TPM_VID_WINBOND 0x1050
>> #define TPM_VID_STM 0x104A
>> #define TPM_VID_ATML 0x1114
>> +#define TPM_VID_IFX 0x15D1
>> enum tpm_chip_flags {
>> TPM_CHIP_FLAG_BOOTSTRAPPED = BIT(0),
>
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