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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>,
	Jason@zx2c4.com, linux-integrity@vger.kernel.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Mario Limonciello <mario.limonciello@amd.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Linux kernel regressions list <regressions@lists.linux.dev>
Subject: Re: [PATCH 1/1] tpm: disable hwrng for fTPM on some AMD designs
Date: Sat, 18 Feb 2023 00:35:42 +0200	[thread overview]
Message-ID: <Y/ABPhpMQrQgQ72l@kernel.org> (raw)
In-Reply-To: <50b5498c-38fb-e2e8-63f0-3d5bbc047737@leemhuis.info>

On Fri, Feb 17, 2023 at 04:18:39PM +0100, Thorsten Leemhuis wrote:
> On 14.02.23 21:19, Mario Limonciello wrote:
> > AMD has issued an advisory indicating that having fTPM enabled in
> > BIOS can cause "stuttering" in the OS.  This issue has been fixed
> > in newer versions of the fTPM firmware, but it's up to system
> > designers to decide whether to distribute it.
> > 
> > This issue has existed for a while, but is more prevalent starting
> > with kernel 6.1 because commit b006c439d58db ("hwrng: core - start
> > hwrng kthread also for untrusted sources") started to use the fTPM
> > for hwrng by default. However, all uses of /dev/hwrng result in
> > unacceptable stuttering.
> > 
> > So, simply disable registration of the defective hwrng when detecting
> > these faulty fTPM versions.
> 
> Hmm, no reply since Mario posted this.
> 
> Jarkko, James, what's your stance on this? Does the patch look fine from
> your point of view? And does the situation justify merging this on the
> last minute for 6.2? Or should we merge it early for 6.3 and then
> backport to stable?
> 
> Ciao, Thorsten

As I stated in earlier response: do we want to forbid tpm_crb in this case
or do we want to pass-through with a faulty firmware?

Not weighting either choice here I just don't see any motivating points
in the commit message to pick either, that's all.

BR, Jarkko

  reply	other threads:[~2023-02-17 22:35 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-14 20:19 [PATCH 0/1] Avoid triggering an fTPM bug from kernel Mario Limonciello
2023-02-14 20:19 ` [PATCH 1/1] tpm: disable hwrng for fTPM on some AMD designs Mario Limonciello
2023-02-17 15:18   ` Thorsten Leemhuis
2023-02-17 22:35     ` Jarkko Sakkinen [this message]
2023-02-18  2:25       ` Limonciello, Mario
2023-02-21 22:53         ` Jarkko Sakkinen
2023-02-21 23:10           ` Limonciello, Mario
2023-02-27 10:57             ` Thorsten Leemhuis
2023-02-27 11:14               ` Jarkko Sakkinen
2023-02-27 11:16                 ` Jarkko Sakkinen
2023-02-17 22:05   ` Jarkko Sakkinen
2023-07-27 15:38   ` Daniil Stas
2023-07-27 15:42     ` Mario Limonciello
2023-07-27 16:39       ` Daniil Stas
2023-07-27 16:41         ` Mario Limonciello
2023-07-27 16:50           ` Daniil Stas
2023-07-27 16:51             ` Mario Limonciello
2023-07-27 17:05               ` Daniil Stas
2023-07-28 20:41                 ` Linus Torvalds
2023-07-28 21:01                   ` Limonciello, Mario
2023-07-28 21:38                     ` Linus Torvalds
2023-07-28 21:47                       ` Limonciello, Mario
     [not found]                   ` <CUGAV1Y993FB.1O2Q691015Z2C@seitikki>
2023-07-31 19:05                     ` Linus Torvalds
2023-07-31 19:18                       ` Limonciello, Mario
2023-07-31 19:30                         ` Linus Torvalds
2023-07-31 21:57                           ` Limonciello, Mario
2023-07-31 23:28                             ` Linus Torvalds
2023-07-31 23:40                               ` Jason A. Donenfeld
2023-08-01  3:04                                 ` Mario Limonciello
2023-08-01 11:36                                   ` Mateusz Schyboll
2023-08-01 18:52                                   ` Jarkko Sakkinen
2023-08-01 18:55                                     ` Jarkko Sakkinen
2023-08-01 18:28                       ` Jarkko Sakkinen
2023-08-01 18:42                         ` Linus Torvalds
2023-08-01 18:51                           ` Mario Limonciello
2023-08-01 19:09                           ` Jarkko Sakkinen
2023-08-02 23:13                             ` Jerry Snitselaar
2023-08-03  0:34                               ` Stefan Berger
2023-07-31 21:44                     ` Limonciello, Mario
2023-07-28 19:30     ` Jarkko Sakkinen
2023-07-28 20:18       ` Daniil Stas
2023-07-31 10:14         ` Jarkko Sakkinen
2023-07-31 10:28           ` Daniil Stas
2023-07-31 11:07             ` Jarkko Sakkinen

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