RE: [PATCH v5 16/17] tpm: take TPM chip power gating out of tpm_transmit()

From: "Winkler, Tomas" <tomas.winkler@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>
Cc: "linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	"Struk, Tadeusz" <tadeusz.struk@intel.com>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	"Nayna Jain" <nayna@linux.ibm.com>,
	Peter Huewe <peterhuewe@gmx.de>, "Jason Gunthorpe" <jgg@ziepe.ca>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v5 16/17] tpm: take TPM chip power gating out of tpm_transmit()
Date: Thu, 8 Nov 2018 18:38:59 +0000	[thread overview]
Message-ID: <5B8DA87D05A7694D9FA63FD143655C1B9DA18602@hasmsx108.ger.corp.intel.com> (raw)
In-Reply-To: <20181108141541.12832-17-jarkko.sakkinen@linux.intel.com>


> Call tpm_chip_start() and tpm_chip_stop() in
> 
> * tpm_try_get_ops() and tpm_put_ops()
> * tpm_chip_register()
> * tpm2_del_space()
> 
> And remove these calls from tpm_transmit(). The core reason for this change
> is that in tpm_vtpm_proxy a locality change requires a virtual TPM command
> (a command made up just for that driver).
> 
I don't think you can do that,  locality has to be request for each command, as  for example tboot can request higher locality any time. 
Same for cmd_ready()/go_idle() powergatin, you will prevent the whole platform entering power save state.
Thanks
Tomas


> The consequence of this is that this commit removes the remaining nested
> calls.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
>  drivers/char/tpm/tpm-chip.c       | 19 ++++++-------------
>  drivers/char/tpm/tpm-interface.c  |  4 ----
>  drivers/char/tpm/tpm.h            |  9 ---------
>  drivers/char/tpm/tpm2-space.c     |  5 ++++-
>  drivers/char/tpm/tpm_vtpm_proxy.c |  3 +--
>  5 files changed, 11 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index
> 65f1561eba81..87570182f75e 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -41,9 +41,6 @@ static int tpm_request_locality(struct tpm_chip *chip,
> unsigned int flags)  {
>  	int rc;
> 
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>  	if (!chip->ops->request_locality)
>  		return 0;
> 
> @@ -59,9 +56,6 @@ static void tpm_relinquish_locality(struct tpm_chip
> *chip, unsigned int flags)  {
>  	int rc;
> 
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return;
> -
>  	if (!chip->ops->relinquish_locality)
>  		return;
> 
> @@ -74,9 +68,6 @@ static void tpm_relinquish_locality(struct tpm_chip
> *chip, unsigned int flags)
> 
>  static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)  {
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>  	if (!chip->ops->cmd_ready)
>  		return 0;
> 
> @@ -85,9 +76,6 @@ static int tpm_cmd_ready(struct tpm_chip *chip,
> unsigned int flags)
> 
>  static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)  {
> -	if (flags & TPM_TRANSMIT_NESTED)
> -		return 0;
> -
>  	if (!chip->ops->go_idle)
>  		return 0;
> 
> @@ -169,7 +157,7 @@ int tpm_try_get_ops(struct tpm_chip *chip)
>  		goto out_lock;
> 
>  	mutex_lock(&chip->tpm_mutex);
> -	return 0;
> +	return tpm_chip_start(chip, 0);
>  out_lock:
>  	up_read(&chip->ops_sem);
>  	put_device(&chip->dev);
> @@ -186,6 +174,7 @@ EXPORT_SYMBOL_GPL(tpm_try_get_ops);
>   */
>  void tpm_put_ops(struct tpm_chip *chip)  {
> +	tpm_chip_stop(chip, 0);
>  	mutex_unlock(&chip->tpm_mutex);
>  	up_read(&chip->ops_sem);
>  	put_device(&chip->dev);
> @@ -563,7 +552,11 @@ int tpm_chip_register(struct tpm_chip *chip)  {
>  	int rc;
> 
> +	rc = tpm_chip_start(chip, 0);
> +	if (rc)
> +		return rc;
>  	rc = tpm_auto_startup(chip);
> +	tpm_chip_stop(chip, 0);
>  	if (rc)
>  		return rc;
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-
> interface.c
> index 888c9923fca1..5c04c0d9aaba 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -168,11 +168,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8
> *buf, size_t bufsiz,
>  	memcpy(save, buf, save_size);
> 
>  	for (;;) {
> -		ret = tpm_chip_start(chip, flags);
> -		if (ret)
> -			return ret;
>  		ret = tpm_try_transmit(chip, buf, bufsiz, flags);
> -		tpm_chip_stop(chip, flags);
> 
>  		rc = be32_to_cpu(header->return_code);
>  		if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING) diff --
> git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index
> c42a75710b70..f9d56dfd0d20 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -485,15 +485,6 @@ extern const struct file_operations tpm_fops;
> extern const struct file_operations tpmrm_fops;  extern struct idr
> dev_nums_idr;
> 
> -/**
> - * enum tpm_transmit_flags - flags for tpm_transmit()
> - *
> - * %TPM_TRANSMIT_NESTED:	discard setup steps (power management,
> locality)
> - */
> -enum tpm_transmit_flags {
> -	TPM_TRANSMIT_NESTED      = BIT(0),
> -};
> -
>  ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
>  		     unsigned int flags);
>  ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_buf *buf, diff -
> -git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> index 341d4b90ba2f..8ed063b54040 100644
> --- a/drivers/char/tpm/tpm2-space.c
> +++ b/drivers/char/tpm/tpm2-space.c
> @@ -60,7 +60,10 @@ int tpm2_init_space(struct tpm_space *space)  void
> tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)  {
>  	mutex_lock(&chip->tpm_mutex);
> -	tpm2_flush_sessions(chip, space);
> +	if (!tpm_chip_start(chip, 0)) {
> +		tpm2_flush_sessions(chip, space);
> +		tpm_chip_stop(chip, 0);
> +	}
>  	mutex_unlock(&chip->tpm_mutex);
>  	kfree(space->context_buf);
>  	kfree(space->session_buf);
> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c
> b/drivers/char/tpm/tpm_vtpm_proxy.c
> index e8a1da2810a9..a4bb60e163cc 100644
> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> @@ -417,8 +417,7 @@ static int vtpm_proxy_request_locality(struct
> tpm_chip *chip, int locality)
> 
>  	proxy_dev->state |= STATE_DRIVER_COMMAND;
> 
> -	rc = tpm_transmit_cmd(chip, &buf, 0, TPM_TRANSMIT_NESTED,
> -			      "attempting to set locality");
> +	rc = tpm_transmit_cmd(chip, &buf, 0, 0, "attempting to set locality");
> 
>  	proxy_dev->state &= ~STATE_DRIVER_COMMAND;
> 
> --
> 2.19.1