tpmdd-devel.lists.sourceforge.net archive mirror
 help / color / mirror / Atom feed
From: Nayna <nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
To: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: patrickc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org,
	jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org,
	linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-ima-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: [PATCH 1/4] tpm: ignore burstcount to improve tpm_tis send() performance.
Date: Wed, 6 Sep 2017 18:28:38 +0530	[thread overview]
Message-ID: <59AFF0FE.5080500@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170906125643.5070-6-nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>

Please ignore these one.. My command took patches recursively from 
directory also.

Sorry for this.

Thanks & Regards,
    - Nayna

On 09/06/2017 06:26 PM, Nayna Jain wrote:
> The TPM burstcount status indicates the number of bytes that can
> be sent to the TPM without causing bus wait states.  Effectively,
> it is the number of empty bytes in the command FIFO. Further,
> some TPMs have a static burstcount, when the value remains zero
> until the entire FIFO is empty.
>
> This patch adds an optimization to check for burstcount only once.
> And if it is valid, it writes all the bytes at once, permitting
> wait states. The performance of a 34 byte extend on a TPM 1.2 with
> an 8 byte burstcount improved from 41 msec to 14 msec.
>
> This functionality is enabled only by passing module
> parameter ignore_burst_count=1. By default, this parameter
> is disabled.
>
> Suggested-by: Ken Goldman <kgold-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org> in
> conjunction with the TPM Device Driver work group.
> Signed-off-by: Nayna Jain <nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Acked-by: Mimi Zohar <zohar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> ---
>   Documentation/admin-guide/kernel-parameters.txt |  8 ++++++++
>   drivers/char/tpm/tpm_tis_core.c                 | 24 +++++++++++++++++++++---
>   2 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4e303be83df6..3c59bb91e1ee 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1465,6 +1465,14 @@
>   			mode generally follows that for the NaN encoding,
>   			except where unsupported by hardware.
>
> +	ignore_burst_count [TPM_TIS_CORE]
> +			tpm_tis_core driver queries for the burstcount before
> +			every send call in a loop. However, it causes delay to
> +			the send command for TPMs with low burstcount value.
> +			Setting this value to 1, will make driver to query for
> +			burstcount only once in the loop to improve the
> +			performance. By default, its value is set to 0.
> +
>   	ignore_loglevel	[KNL]
>   			Ignore loglevel setting - this will print /all/
>   			kernel messages to the console. Useful for debugging.
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 63bc6c3b949e..6b9bf4c4d434 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -31,6 +31,11 @@
>   #include "tpm.h"
>   #include "tpm_tis_core.h"
>
> +static bool ignore_burst_count = false;
> +module_param(ignore_burst_count, bool, 0444);
> +MODULE_PARM_DESC(ignore_burst_count,
> +		"Ignore burstcount value while writing data");
> +
>   /* Before we attempt to access the TPM we must see that the valid bit is set.
>    * The specification says that this bit is 0 at reset and remains 0 until the
>    * 'TPM has gone through its self test and initialization and has established
> @@ -256,6 +261,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>   {
>   	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>   	int rc, status, burstcnt;
> +	int sendcnt;
>   	size_t count = 0;
>   	bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
>
> @@ -271,19 +277,31 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>   	}
>
>   	while (count < len - 1) {
> +
> +		/*
> +		 * Get the initial burstcount to ensure TPM is ready to
> +		 * accept data, even when waiting for burstcount is disabled.
> +		 */
>   		burstcnt = get_burstcount(chip);
>   		if (burstcnt < 0) {
>   			dev_err(&chip->dev, "Unable to read burstcount\n");
>   			rc = burstcnt;
>   			goto out_err;
>   		}
> -		burstcnt = min_t(int, burstcnt, len - count - 1);
> +
> +		if (ignore_burst_count)
> +			sendcnt = len - 1;
> +		else
> +			sendcnt = min_t(int, burstcnt, len - count - 1);
> +
>   		rc = tpm_tis_write_bytes(priv, TPM_DATA_FIFO(priv->locality),
> -					 burstcnt, buf + count);
> +					 sendcnt, buf + count);
>   		if (rc < 0)
>   			goto out_err;
>
> -		count += burstcnt;
> +		count += sendcnt;
> +		if (ignore_burst_count)
> +			continue;
>
>   		if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
>   					&priv->int_queue, false) < 0) {
>


------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot

  parent reply	other threads:[~2017-09-06 12:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-06 12:56 [PATCH v2 0/4] additional TPM performance improvements Nayna Jain
2017-09-06 12:56 ` [PATCH v2 3/4] tpm: reduce tpm_msleep() time in get_burstcount() Nayna Jain
2017-09-13  1:00   ` Jarkko Sakkinen
2017-09-15 12:40     ` Nayna Jain
     [not found] ` <20170906125643.5070-1-nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-09-06 12:56   ` [PATCH v2 1/4] tpm: ignore burstcount to improve tpm_tis send() performance Nayna Jain
2017-09-06 16:12     ` Jason Gunthorpe
2017-09-13 18:52       ` [tpmdd-devel] " Ken Goldman
     [not found]         ` <3c418974-a4c7-518e-b218-f6373c10209e-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-09-13 19:01           ` Peter Huewe
2017-09-13  0:45     ` Jarkko Sakkinen
     [not found]       ` <20170912222010.ltm76m5vy2kupydi-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
2017-09-13 18:39         ` Peter Huewe
2017-09-13 23:10           ` Jarkko Sakkinen
2017-09-15 12:29             ` Nayna Jain
2017-09-15 15:19               ` Jarkko Sakkinen
2017-09-06 12:56   ` [PATCH v2 2/4] tpm: define __wait_for_tpm_stat to specify variable polling sleep time Nayna Jain
2017-09-13  0:58     ` Jarkko Sakkinen
2017-09-15 12:37       ` Nayna Jain
2017-09-15 15:20         ` Jarkko Sakkinen
2017-09-06 12:56   ` [PATCH v2 4/4] tpm: use tpm_msleep() value as max delay Nayna Jain
2017-09-13  0:47     ` Jarkko Sakkinen
2017-09-14  9:25       ` Nayna Jain
2017-09-14 12:28         ` Jarkko Sakkinen
2017-09-06 12:56   ` [PATCH 2/4] tpm: define __wait_for_tpm_stat to specify variable polling sleep time Nayna Jain
2017-09-06 12:58     ` Nayna
2017-09-06 12:56 ` [PATCH 1/4] tpm: ignore burstcount to improve tpm_tis send() performance Nayna Jain
     [not found]   ` <20170906125643.5070-6-nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-09-06 12:58     ` Nayna [this message]
2017-09-07 16:18 ` [PATCH v2 0/4] additional TPM performance improvements Jarkko Sakkinen
2017-09-11 15:20 ` [tpmdd-devel] " Alexander.Steffen

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=59AFF0FE.5080500@linux.vnet.ibm.com \
    --to=nayna-23vcf4htsmix0ybbhkvfkdbpr1lh4cv8@public.gmane.org \
    --cc=jarkko.sakkinen-VuQAYsv1563Yd54FQh9/CA@public.gmane.org \
    --cc=jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org \
    --cc=linux-ima-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \
    --cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
    --cc=patrickc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org \
    --cc=tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org \
    --subject='Re: [PATCH 1/4] tpm: ignore burstcount to improve tpm_tis send() performance.' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).