From: Jarkko Sakkinen <jarkko@kernel.org>
To: Borys Movchan <borysmn@axis.com>
Cc: Borys Movchan <Borys.Movchan@axis.com>,
Peter Huewe <peterhuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
kernel <kernel@axis.com>,
"linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] tpm: Add Upgrade/Reduced mode support for TPM2 modules
Date: Mon, 2 Aug 2021 11:35:28 +0300 [thread overview]
Message-ID: <20210802083528.yayuwm6mlkowrsh2@kernel.org> (raw)
In-Reply-To: <b12dad90-c9ed-2331-7e96-78ca5c3994e8@axis.com>
On Fri, Jul 30, 2021 at 04:24:01PM +0200, Borys Movchan wrote:
> On 7/28/21 11:58 PM, Jarkko Sakkinen wrote:
> > On Wed, Jul 28, 2021 at 12:57:30PM +0200, Borys Movchan wrote:
> > > If something went wrong during the TPM firmware upgrade,
> > > like power failure or the firmware image file get corrupted,
> > > the TPM might end up in Upgrade or Failure mode upon the
> > > next start. The state is persistent between the TPM power
> > > cycle/restart.
> > >
> > > According to TPM specification:
> > > * If the TPM is in Upgrade mode, it will answer with
> > > TPM2_RC_UPGRADE to all commands except Field Upgrade
> > > related ones.
> > > * If the TPM is in Failure mode, it will allow performing
> > > TPM initialization but will not provide any crypto
> > > operations. Will happily respond to Field Upgrade calls.
> > >
> > > The fix adds the possibility to detect an active state of
> > > the TPM and gives the user-space a chance to finish the
> > > firmware upgrade/recover the TPM.
> >
> > This is different than telling what the patch does. It's just
> > describing a goal, but does not describe how the driver is
> > changed, and reasons for doing that.
> >
> > For instance, you check 'limited_mode' flag in a few sites.
> > How can I know that those are exactly the locations where this
> > needs to be done?
> >
>
> Seems like I got what you are looking for. Let me try to explain the
> reasoning
> and doubts regarding what I meant under my change.
Please try to nail this in the commit message instead, and I'll
then review that.
/Jarkko
prev parent reply other threads:[~2021-08-02 8:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-28 10:57 [PATCH v2] tpm: Add Upgrade/Reduced mode support for TPM2 modules Borys Movchan
2021-07-28 21:58 ` Jarkko Sakkinen
2021-07-30 14:24 ` Borys Movchan
2021-08-02 8:35 ` Jarkko Sakkinen [this message]
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=20210802083528.yayuwm6mlkowrsh2@kernel.org \
--to=jarkko@kernel.org \
--cc=Borys.Movchan@axis.com \
--cc=borysmn@axis.com \
--cc=jgg@ziepe.ca \
--cc=kernel@axis.com \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peterhuewe@gmx.de \
/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).