Date:   Mon, 26 Jul 2021 17:25:23 +0200
From:   Jens Wiklander <jens.wiklander@...aro.org>
To:     Sumit Garg <sumit.garg@...aro.org>
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        OP-TEE TrustedFirmware <op-tee@...ts.trustedfirmware.org>,
        Marc Bonnici <marc.bonnici@....com>,
        Jerome Forissier <jerome@...issier.org>,
        Sughosh Ganu <sughosh.ganu@...aro.org>
Subject: Re: [PATCH v3 0/5] Add FF-A support in OP-TEE driver

Hi Sumit,

On Mon, Jul 26, 2021 at 1:41 PM Sumit Garg <sumit.garg@...aro.org> wrote:
>
> On Mon, 26 Jul 2021 at 16:25, Sudeep Holla <sudeep.holla@....com> wrote:
> >
> > On Mon, Jul 26, 2021 at 03:59:36PM +0530, Sumit Garg wrote:
> > > Hi Jens,
> > >
> > > On Thu, 22 Jul 2021 at 17:48, Jens Wiklander <jens.wiklander@...aro.org> wrote:
> > > >
> > > > Hi all,
> > > >
> > > > This adds supports for the OP-TEE driver to communicate with secure world
> > > > using FF-A [1] as transport.
> > > >
> > > > There is one change to the TEE subsystem with "tee: add sec_world_id to
> > > > struct tee_shm" to add support for holding globally unique handle assigned
> > > > by the FF-A. This is a field that I believe could useful for the AMDTEE
> > > > driver too.
> > > >
> > > > For communication the OP-TEE message protocol is still used, but with a new
> > > > type of memory reference, struct optee_msg_param_fmem, to carry the
> > > > information needed by FF-A. The OP-TEE driver is refactored internally with
> > > > to sets of callbacks, one for the old SMC based communication and another
> > > > set with FF-A as transport. The functions relating to the SMC based ABI
> > > > are moved to smc_abi.c while the FF-A based ABI is added in a ffa_abi.c.
> > > >
> > > > There is also a difference in how the drivers are instantiated. With the
> > > > SMC based transport we have a platform driver, module_platform_driver(),
> > > > today which we're keeping as is for this configuration. In a FF-A system we
> > > > have a FF-A driver, module_ffa_driver(), instead.
> > > >
> > > > The OP-TEE driver can be compiled for both targets at the same time and
> > > > it's up to runtime configuration (device tree or ACPI) to decide how it's
> > > > initialized. Note that it's only the old SMC based driver instance that
> > > > need device tree or ACPI to initialize. The FF-A based driver relies on the
> > > > FF-A bus instead.
> > > >
> > > > This can be tested QEMU
> > > > The repo for SPMC at S-EL1 retrieved by
> > > > repo init -u https://github.com/jenswi-linaro/manifest.git -m
> > > > qemu_v8.xml -b ffav4_spmc
> > > > repo sync
> > > > # Then checkout the branch optee_ffa_v3 from
> > > > # git://git.linaro.org/people/jens.wiklander/linux-tee.git
> > > > # in the linux directory
> > > >
> > > > To build do:
> > > > cd build
> > > > make toolchains
> > > > make all
> > > >
> > > > To boot:
> > > > make run-only
> > > >
> > > > Test with xtest, perhaps only with the command "xtest 1004" in case you're
> > > > not interested in too many tests.
> > >
> > > Thanks Jens for sharing instructions to test this feature. So I tried
> > > to reproduce using following repo versions:
> > >
> > > linux-tee, branch: optee_ffa_v3
> > > trusted-firmware-a, branch: ffav4_sel1_spmc
> > > build, branch: ffav4_spmc
> > >
> > > and rest of the repos synced to the latest version as per upstream
> > > qemu_v8.xml [1] but I don't see OP-TEE driver being probed during boot
> > > [2]. Am I missing something?
> > >
> > > [1] https://github.com/OP-TEE/manifest/blob/master/qemu_v8.xml
> > > [2]
> > > Welcome to Buildroot, type root or test to login
> > > buildroot login: root
> > > # dmesg | grep optee
> > >
> >
> > Do you see ARM FF-A driver initialised successfully ?
> > You must see "ARM FF-A Version 1.0 found" or something similar based on
> > the actual version supported.
> >
> > If so, can you check if the partitions are correctly populated by
> > the driver using the discover API.
> >
> > $ grep "" /sys/bus/arm_ffa/devices/*/uuid
> >
> > If uuid reads zeros, then the devices are populated, just the matching
> > driver is not found(due to the workaround for v1.0 spec)
> >
>
> It turns out to be an issue with my build environment, I re-built from
> scratch and I could see OP-TEE being probed successfully:
>
> # dmesg | grep FF-A
> [    0.356382] ARM FF-A: Version 1.0 found
> #
> # cat /sys/bus/arm_ffa/devices/arm-ffa-8001/uuid
> 486178e0-e7f8-11e3-bc5e-0002a5d5c51b
> #
> # dmesg | grep optee
> [    4.991472] optee: revision 3.14 (49dbb9ef)
> [    5.010110] optee: initialized driver
> #

That's good.

> From xtest logs it looks like the pseudo TA interface isn't working for me:
>
> * regression_1001 Core self tests
>  - 1001 -   skip test, pseudo TA not found
>   regression_1001 OK
>
> * regression_1002 PTA parameters
>  - 1002 -   skip test, pseudo TA not found
>   regression_1002 OK
>
> * regression_1003 Core internal read/write mutex
>  - 1003 -   skip test, pseudo TA not found
>   regression_1003 OK

The test PTAs are disabled by default.

>
> Similarly, pseudo TAs acting as TEE bus devices doesn't work as well
> as I see following devices directory being empty:
>
> # ls /sys/bus/tee/devices/
> #
>
> As otherwise with OP-TEE SMC ABI, we should have at least the default
> pseudo TA [1] kernel device there.
>
> So is pseudo TA functional with this new FF-A interface?

Yes, everything is supposed to work.

Cheers,
Jens

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