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From: Jens Wiklander <jens.wiklander@linaro.org>
Date: Wed, 3 Apr 2024 10:54:03 +0200
Message-ID: <CAHUa44FWRizv39wRJ8ku2v02pDB8_J6BmSk27NrA_UHv4cqNkw@mail.gmail.com>
Subject: Re: [PATCH v3 1/3] rpmb: add Replay Protected Memory Block (RPMB) subsystem
To: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, 
	op-tee@lists.trustedfirmware.org, 
	Shyam Saini <shyamsaini@linux.microsoft.com>, Ulf Hansson <ulf.hansson@linaro.org>, 
	Jerome Forissier <jerome.forissier@linaro.org>, Sumit Garg <sumit.garg@linaro.org>, 
	Ilias Apalodimas <ilias.apalodimas@linaro.org>, Bart Van Assche <bvanassche@acm.org>, 
	Randy Dunlap <rdunlap@infradead.org>, Ard Biesheuvel <ardb@kernel.org>, Arnd Bergmann <arnd@arndb.de>, 
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Tomas Winkler <tomas.winkler@intel.com>, 
	=?UTF-8?B?QWxleCBCZW5uw6ll?= <alex.bennee@linaro.org>
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On Tue, Mar 5, 2024 at 1:24=E2=80=AFPM Linus Walleij <linus.walleij@linaro.=
org> wrote:
>
> Hi Jens,
>
> thanks for your patch!
>
> On Tue, Feb 27, 2024 at 4:31=E2=80=AFPM Jens Wiklander
> <jens.wiklander@linaro.org> wrote:
>
> > A number of storage technologies support a specialised hardware
> > partition designed to be resistant to replay attacks. The underlying
> > HW protocols differ but the operations are common. The RPMB partition
> > cannot be accessed via standard block layer, but by a set of specific
> > RPMB commands: WRITE, READ, GET_WRITE_COUNTER, and PROGRAM_KEY. Such a
> > partition provides authenticated and replay protected access, hence
> > suitable as a secure storage.
> >
> > The initial aim of this patch is to provide a simple RPMB driver
> > interface which can be accessed by the optee driver to facilitate early
> > RPMB access to OP-TEE OS (secure OS) during the boot time.
> >
> > A TEE device driver can claim the RPMB interface, for example, via
> > rpmb_interface_register() or rpmb_dev_find_device(). The RPMB driver
> > provides a callback to route RPMB frames to the RPMB device accessible
> > via rpmb_route_frames().
> >
> > The detailed operation of implementing the access is left to the TEE
> > device driver itself.
> >
> > Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
> > Signed-off-by: Alex Benn=C3=A9e <alex.bennee@linaro.org>
> > Signed-off-by: Shyam Saini <shyamsaini@linux.microsoft.com>
> > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
>
> I would mention in the commit that the subsystem is currently
> only used with eMMC but is designed to be used also by UFS
> and NVME. Nevertheless, no big deal so:
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>
> > +config RPMB
> > +       tristate "RPMB partition interface"
> > +       depends on MMC
>
> depends on MMC || SCSI_UFSHCD || NVME_CORE
> ?
>
> Or do we want to hold it off until we implement the backends?

Correct, I think we should hold it off until then.

Thanks,
Jens

>
> Yours,
> Linus Walleij