All of lore.kernel.org
 help / color / mirror / Atom feed
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Leendert van Doorn <leendert@paramecium.org>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Nayna Jain <nayna@linux.vnet.ibm.com>
Cc: "Alexander.Steffen@infineon.com" <Alexander.Steffen@infineon.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"peterhuewe@gmx.de" <peterhuewe@gmx.de>,
	"tpmdd@selhorst.net" <tpmdd@selhorst.net>,
	"patrickc@us.ibm.com" <patrickc@us.ibm.com>,
	"Safford, David (GE Global Research, US)" <david.safford@ge.com>
Subject: Re: [PATCH v4 2/4] tpm: ignore burstcount to improve tpm_tis send() performance
Date: Mon, 27 Nov 2017 08:22:28 -0500	[thread overview]
Message-ID: <1511788948.4361.39.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <694703AB-68E1-4026-937C-61DBBE08DB4B@paramecium.org>

Hi, Leendert!

On Mon, 2017-11-27 at 07:08 +0000, Leendert van Doorn wrote:
> Hmm, this is almost 20 years old code (
> 
> I think the original code did a burst write and didn't check for
> error conditions until the very last byte write. I seem to remember
> that there was some text in the original standard to that effect
> (this may have gone back as far as IBM's ESS spec).

I really appreciate your responding with your recollections.

> The current code does check for error conditions after each write
> byte(s) so I don't think there is any reason for this anymore.
> Changing the while condition to count < len and setting burstcnt =
> min_t(int, burstcnt, len - count) and remove the
> tpm_tis_write8/wait_for_tpm_stat/tpm_tis_status clauses after the
> while loop should be sufficient.

The context for my question was about removing the while loop and
sending all of the data at once, relying on the bus wait states.
 Before making the change, I wanted to make sure there wasn't anything
special about the last byte.

thanks,

Mimi

WARNING: multiple messages have this Message-ID (diff)
From: zohar@linux.vnet.ibm.com (Mimi Zohar)
To: linux-security-module@vger.kernel.org
Subject: [PATCH v4 2/4] tpm: ignore burstcount to improve tpm_tis send() performance
Date: Mon, 27 Nov 2017 08:22:28 -0500	[thread overview]
Message-ID: <1511788948.4361.39.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <694703AB-68E1-4026-937C-61DBBE08DB4B@paramecium.org>

Hi, Leendert!

On Mon, 2017-11-27 at 07:08 +0000, Leendert van Doorn wrote:
> Hmm, this is almost 20 years old code (
> 
> I think the original code did a burst write and didn't check for
> error conditions until the very last byte write. I seem to remember
> that there was some text in the original standard to that effect
> (this may have gone back as far as IBM's ESS spec).

I really appreciate your responding with your recollections.

> The current code does check for error conditions after each write
> byte(s) so I don't think there is any reason for this anymore.
> Changing the while condition to count < len and setting burstcnt =
> min_t(int, burstcnt, len - count) and remove the
> tpm_tis_write8/wait_for_tpm_stat/tpm_tis_status clauses after the
> while loop should be sufficient.

The context for my question was about removing the while loop and
sending all of the data at once, relying on the bus wait states.
?Before making the change, I wanted to make sure there wasn't anything
special about the last byte.

thanks,

Mimi

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

WARNING: multiple messages have this Message-ID (diff)
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Leendert van Doorn <leendert@paramecium.org>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	Nayna Jain <nayna@linux.vnet.ibm.com>
Cc: "Alexander.Steffen@infineon.com" <Alexander.Steffen@infineon.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	"linux-security-module@vger.kernel.org"
	<linux-security-module@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"peterhuewe@gmx.de" <peterhuewe@gmx.de>,
	"tpmdd@selhorst.net" <tpmdd@selhorst.net>,
	"patrickc@us.ibm.com" <patrickc@us.ibm.com>,
	"Safford, David (GE Global Research, US)" <david.safford@ge.com>
Subject: Re: [PATCH v4 2/4] tpm: ignore burstcount to improve tpm_tis send() performance
Date: Mon, 27 Nov 2017 08:22:28 -0500	[thread overview]
Message-ID: <1511788948.4361.39.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <694703AB-68E1-4026-937C-61DBBE08DB4B@paramecium.org>

Hi, Leendert!

On Mon, 2017-11-27 at 07:08 +0000, Leendert van Doorn wrote:
> Hmm, this is almost 20 years old code (
> 
> I think the original code did a burst write and didn't check for
> error conditions until the very last byte write. I seem to remember
> that there was some text in the original standard to that effect
> (this may have gone back as far as IBM's ESS spec).

I really appreciate your responding with your recollections.

> The current code does check for error conditions after each write
> byte(s) so I don't think there is any reason for this anymore.
> Changing the while condition to count < len and setting burstcnt =
> min_t(int, burstcnt, len - count) and remove the
> tpm_tis_write8/wait_for_tpm_stat/tpm_tis_status clauses after the
> while loop should be sufficient.

The context for my question was about removing the while loop and
sending all of the data at once, relying on the bus wait states.
 Before making the change, I wanted to make sure there wasn't anything
special about the last byte.

thanks,

Mimi

  reply	other threads:[~2017-11-27 13:22 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-17 20:32 [PATCH v4 0/4] additional TPM performance improvements Nayna Jain
2017-10-17 20:32 ` Nayna Jain
2017-10-17 20:32 ` [PATCH v4 1/4] tpm: move wait_for_tpm_stat() to respective driver files Nayna Jain
2017-10-17 20:32   ` Nayna Jain
2017-10-19 14:21   ` Jarkko Sakkinen
2017-10-19 14:21     ` Jarkko Sakkinen
2017-10-19 17:00     ` Alexander.Steffen
2017-10-19 17:00       ` Alexander.Steffen at infineon.com
2017-10-20  8:56       ` Jarkko Sakkinen
2017-10-20  8:56         ` Jarkko Sakkinen
2017-10-23 13:32         ` Nayna Jain
2017-10-23 13:32           ` Nayna Jain
2017-10-23 13:32           ` Nayna Jain
2017-10-24 13:45           ` Jarkko Sakkinen
2017-10-24 13:45             ` Jarkko Sakkinen
2017-10-17 20:32 ` [PATCH v4 2/4] tpm: ignore burstcount to improve tpm_tis send() performance Nayna Jain
2017-10-17 20:32   ` Nayna Jain
2017-10-18 15:25   ` Jarkko Sakkinen
2017-10-18 15:25     ` Jarkko Sakkinen
2017-10-19 14:23   ` Jarkko Sakkinen
2017-10-19 14:23     ` Jarkko Sakkinen
2017-10-20 14:42   ` Alexander.Steffen
2017-10-20 14:42     ` Alexander.Steffen at infineon.com
2017-10-20 18:02     ` Ken Goldman
2017-10-20 18:02       ` Ken Goldman
2017-10-23  2:57     ` Jarkko Sakkinen
2017-10-23  2:57       ` Jarkko Sakkinen
2017-11-07 18:29     ` Nayna Jain
2017-11-07 18:29       ` Nayna Jain
2017-11-07 18:29       ` Nayna Jain
2017-11-08 11:32       ` Alexander.Steffen
2017-11-08 11:32         ` Alexander.Steffen at infineon.com
2017-11-16 14:34       ` Alexander.Steffen
2017-11-16 14:34         ` Alexander.Steffen at infineon.com
2017-11-22  6:52       ` Alexander.Steffen
2017-11-22  6:52         ` Alexander.Steffen at infineon.com
2017-11-23 14:47         ` Nayna Jain
2017-11-23 14:47           ` Nayna Jain
2017-11-23 16:19           ` Alexander.Steffen
2017-11-23 16:19             ` Alexander.Steffen at infineon.com
2017-11-26 15:22           ` Jarkko Sakkinen
2017-11-26 15:22             ` Jarkko Sakkinen
2017-11-26 16:37             ` Mimi Zohar
2017-11-26 16:37               ` Mimi Zohar
2017-11-27  7:08               ` Leendert van Doorn
2017-11-27  7:08                 ` Leendert van Doorn
2017-11-27  7:08                 ` Leendert van Doorn
2017-11-27 13:22                 ` Mimi Zohar [this message]
2017-11-27 13:22                   ` Mimi Zohar
2017-11-27 13:22                   ` Mimi Zohar
2017-11-28 20:19                 ` Jarkko Sakkinen
2017-11-28 20:19                   ` Jarkko Sakkinen
2017-11-28 20:19                   ` Jarkko Sakkinen
2017-10-17 20:32 ` [PATCH v4 3/4] tpm: reduce tpm polling delay in tpm_tis_core Nayna Jain
2017-10-17 20:32   ` Nayna Jain
2017-10-18 15:24   ` Jarkko Sakkinen
2017-10-18 15:24     ` Jarkko Sakkinen
2017-10-19 14:22     ` Jarkko Sakkinen
2017-10-19 14:22       ` Jarkko Sakkinen
2017-10-17 20:32 ` [PATCH v4 4/4] tpm: use tpm_msleep() value as max delay Nayna Jain
2017-10-17 20:32   ` Nayna Jain
2017-10-19 14:22   ` Jarkko Sakkinen
2017-10-19 14:22     ` Jarkko Sakkinen

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=1511788948.4361.39.camel@linux.vnet.ibm.com \
    --to=zohar@linux.vnet.ibm.com \
    --cc=Alexander.Steffen@infineon.com \
    --cc=david.safford@ge.com \
    --cc=jarkko.sakkinen@linux.intel.com \
    --cc=leendert@paramecium.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=nayna@linux.vnet.ibm.com \
    --cc=patrickc@us.ibm.com \
    --cc=peterhuewe@gmx.de \
    --cc=tpmdd@selhorst.net \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.