linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: linux-integrity@vger.kernel.org, stable@vger.kernel.org,
	Todd Brandt <todd.e.brandt@intel.com>,
	Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
	Mario Limonciello <mario.limonciello@amd.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] tpm: Enable hwrng only for Pluton on AMD CPUs
Date: Sun, 27 Aug 2023 18:05:50 -0700	[thread overview]
Message-ID: <ct256e7tloa3th4muxmhgvysvod35c4vp2aczuybud3q6747ts@hglky2egrg7y> (raw)
In-Reply-To: <20230822231510.2263255-1-jarkko@kernel.org>

On Wed, Aug 23, 2023 at 02:15:10AM +0300, Jarkko Sakkinen wrote:
> The vendor check introduced by commit 554b841d4703 ("tpm: Disable RNG for
> all AMD fTPMs") doesn't work properly on a number of Intel fTPMs.  On the
> reported systems the TPM doesn't reply at bootup and returns back the
> command code. This makes the TPM fail probe.
> 
> Since only Microsoft Pluton is the only known combination of AMD CPU and
> fTPM from other vendor, disable hwrng otherwise. In order to make sysadmin
> aware of this, print also info message to the klog.
> 
> Cc: stable@vger.kernel.org
> Fixes: 554b841d4703 ("tpm: Disable RNG for all AMD fTPMs")
> Reported-by: Todd Brandt <todd.e.brandt@intel.com>
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217804
> Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> ---
> v3:
> * Forgot to amend config flags.
> v2:
> * CONFIG_X86
> * Removed "Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>"
> * Removed "Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>"
> ---
>  drivers/char/tpm/tpm_crb.c | 33 ++++++++-------------------------
>  1 file changed, 8 insertions(+), 25 deletions(-)
> 

It looks like stable should be pinged as well. I saw a report yesterday for Fedora
where someone is seeing issue where the tpm device no longer shows up with
a 6.4.11 kernel. That kernel pulled in commit 554b841d4703. It pulled in a couple
other tpm commits, and there is practically no info in the bug at this point,
but I'm guessing the probe is failing due to 554b841d4703.


> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index 65ff4d2fbe8d..ea085b14ab7c 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -463,28 +463,6 @@ static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
>  	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
>  }
>  
> -static int crb_check_flags(struct tpm_chip *chip)
> -{
> -	u32 val;
> -	int ret;
> -
> -	ret = crb_request_locality(chip, 0);
> -	if (ret)
> -		return ret;
> -
> -	ret = tpm2_get_tpm_pt(chip, TPM2_PT_MANUFACTURER, &val, NULL);
> -	if (ret)
> -		goto release;
> -
> -	if (val == 0x414D4400U /* AMD */)
> -		chip->flags |= TPM_CHIP_FLAG_HWRNG_DISABLED;
> -
> -release:
> -	crb_relinquish_locality(chip, 0);
> -
> -	return ret;
> -}
> -
>  static const struct tpm_class_ops tpm_crb = {
>  	.flags = TPM_OPS_AUTO_STARTUP,
>  	.status = crb_status,
> @@ -827,9 +805,14 @@ static int crb_acpi_add(struct acpi_device *device)
>  	if (rc)
>  		goto out;
>  
> -	rc = crb_check_flags(chip);
> -	if (rc)
> -		goto out;
> +#ifdef CONFIG_X86
> +	/* A quirk for https://www.amd.com/en/support/kb/faq/pa-410 */
> +	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
> +	    priv->sm != ACPI_TPM2_COMMAND_BUFFER_WITH_PLUTON) {
> +		dev_info(dev, "Disabling hwrng\n");
> +		chip->flags |= TPM_CHIP_FLAG_HWRNG_DISABLED;
> +	}
> +#endif /* CONFIG_X86 */
>  
>  	rc = tpm_chip_register(chip);
>  
> -- 
> 2.39.2
> 


  parent reply	other threads:[~2023-08-28  1:07 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-22 23:15 [PATCH v3] tpm: Enable hwrng only for Pluton on AMD CPUs Jarkko Sakkinen
2023-08-23  8:23 ` Paul Menzel
2023-08-23 17:40   ` Jarkko Sakkinen
2023-08-23 18:58     ` Mario Limonciello
2023-08-27 18:12       ` Jarkko Sakkinen
2023-08-28  0:35         ` Mario Limonciello
2023-08-29  8:38           ` Linux regression tracking (Thorsten Leemhuis)
2023-09-01  8:49             ` Thorsten Leemhuis
2023-09-04 22:32               ` Jarkko Sakkinen
2023-09-05 12:01                 ` Thorsten Leemhuis
2023-09-11 10:40                   ` Jarkko Sakkinen
2023-09-11 10:42                     ` Jarkko Sakkinen
2023-09-04 18:00           ` Jarkko Sakkinen
2023-09-04 18:18             ` Jarkko Sakkinen
2023-08-23 19:24     ` checkpatch complains about Reported-by block (was: [PATCH v3] tpm: Enable hwrng only for Pluton on AMD CPUs) Paul Menzel
2023-08-24  4:43       ` Joe Perches
2023-08-27 18:29         ` Jarkko Sakkinen
2023-08-27 18:26       ` Jarkko Sakkinen
2023-08-28  1:05 ` Jerry Snitselaar [this message]
2023-08-29 19:03 ` [PATCH v3] tpm: Enable hwrng only for Pluton on AMD CPUs Jerry Snitselaar
2023-08-30 18:25   ` Jerry Snitselaar
2023-09-04 20:51     ` Jarkko Sakkinen
2023-09-04 18:12 ` [PATCH v4] " 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=ct256e7tloa3th4muxmhgvysvod35c4vp2aczuybud3q6747ts@hglky2egrg7y \
    --to=jsnitsel@redhat.com \
    --cc=jarkko@kernel.org \
    --cc=jgg@ziepe.ca \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mario.limonciello@amd.com \
    --cc=peterhuewe@gmx.de \
    --cc=stable@vger.kernel.org \
    --cc=todd.e.brandt@intel.com \
    /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 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).