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From: Mimi Zohar <zohar@linux.ibm.com>
To: James Bottomley <James.Bottomley@HansenPartnership.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Omar Sandoval <osandov@osandov.com>,
	Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
	linux-integrity@vger.kernel.org
Subject: Re: [PATCH] tpm_tis: work around status register bug in STMicroelectronics TPM
Date: Tue, 21 Apr 2020 10:36:04 -0400	[thread overview]
Message-ID: <1587479764.5149.27.camel@linux.ibm.com> (raw)
In-Reply-To: <1587421686.3493.2.camel@HansenPartnership.com>

On Mon, 2020-04-20 at 15:28 -0700, James Bottomley wrote:
> On Mon, 2020-04-20 at 23:46 +0300, Jarkko Sakkinen wrote:

<snip>

> But more seriously: Nayna Jain did a series of patches improving the
> time it takes to poll the TPM for operations precisely because the TPM
> PCR extend was going so slowly:
> 
> https://lore.kernel.org/linux-integrity/20180516055125.5685-1-nayna@linux.vnet.ibm.com/

The original reason for us needing to improve the TPM performance was
due to the kernel scheduler change.  Refer to commit a233a0289cf9
("tpm: msleep() delays - replace with usleep_range() in i2c nuvoton
driver").  That scheduler change prevented systems from booting.
 Bisecting the kernel to figure out the problem wasn't very
productive.

At least any TPM changes that affect the TPM performance really need
to take into account IMA requirements.

thanks,

Mimi


  reply	other threads:[~2020-04-21 14:36 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15 22:45 [PATCH] tpm_tis: work around status register bug in STMicroelectronics TPM Omar Sandoval
2020-04-15 23:51 ` James Bottomley
2020-04-16  0:16   ` Omar Sandoval
2020-04-16  0:24     ` Omar Sandoval
2020-04-16 18:02       ` James Bottomley
2020-04-17 23:55         ` Jarkko Sakkinen
2020-04-18  0:12           ` James Bottomley
2020-04-20 20:46             ` Jarkko Sakkinen
2020-04-20 22:28               ` James Bottomley
2020-04-21 14:36                 ` Mimi Zohar [this message]
2020-04-21 20:25                   ` Jarkko Sakkinen
2020-04-21 20:31                     ` Mimi Zohar
2020-04-21 20:23                 ` Jarkko Sakkinen
2020-04-21 22:08                   ` James Bottomley
2020-04-16 17:09   ` Jarkko Sakkinen
2020-04-16 17:56     ` James Bottomley
2020-08-27 15:24   ` Jason Andryuk
2020-08-28 23:18     ` Jarkko Sakkinen
2020-08-29  0:12       ` Jason Andryuk
2020-08-31 13:55         ` Jarkko Sakkinen
2020-09-04 12:03         ` Jarkko Sakkinen
2020-04-16 17:08 ` Jarkko Sakkinen
2020-04-16 18:54   ` Omar Sandoval
2020-04-17 23:54     ` Jarkko Sakkinen

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