linux-kernel - Re: [PATCH v4 1/2] tee: optee: Fix supplicant based device enumeration

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Message-ID: <CAFA6WYO9S8n3uK9DYOMmFX=Sj1nSDFfKErZY4Xe4CM8+SgGhcA@mail.gmail.com>
Date:   Fri, 3 Nov 2023 11:22:15 +0530
From:   Sumit Garg <sumit.garg@...aro.org>
To:     Ilias Apalodimas <ilias.apalodimas@...aro.org>
Cc:     jens.wiklander@...aro.org, op-tee@...ts.trustedfirmware.org,
        jan.kiszka@...mens.com, arnd@...aro.org, ardb@...nel.org,
        jerome.forissier@...aro.org, masahisa.kojima@...aro.org,
        maxim.uvarov@...aro.org, jarkko.sakkinen@...ux.intel.com,
        linux-kernel@...r.kernel.org, diogo.ivo@...mens.com
Subject: Re: [PATCH v4 1/2] tee: optee: Fix supplicant based device enumeration

Hi Ilias,

On Thu, 2 Nov 2023 at 19:58, Ilias Apalodimas
<ilias.apalodimas@...aro.org> wrote:
>
> Hi Sumit,
>
> On Thu, 2 Nov 2023 at 09:31, Sumit Garg <sumit.garg@...aro.org> wrote:
> >
> > Currently supplicant dependent optee device enumeration only registers
> > devices whenever tee-supplicant is invoked for the first time. But it
> > forgets to remove devices when tee-supplicant daemon stops running and
> > closes its context gracefully. This leads to following error for fTPM
> > driver during reboot/shutdown:
> >
> > [   73.466791] tpm tpm0: ftpm_tee_tpm_op_send: SUBMIT_COMMAND invoke error: 0xffff3024
> >
> > Fix this by adding an attribute for supplicant dependent devices so that
> > the user-space service can detect and detach supplicant devices before
> > closing the supplicant:
> >
> > $ for dev in /sys/bus/tee/devices/*; do if [[ -f "$dev/need_supplicant" && -f "$dev/driver/unbind" ]]; \
> >       then echo $(basename "$dev") > $dev/driver/unbind; fi done
> >
> > Reported-by: Jan Kiszka <jan.kiszka@...mens.com>
> > Link: https://github.com/OP-TEE/optee_os/issues/6094
> > Fixes: 5f178bb71e3a ("optee: enable support for multi-stage bus enumeration")
> > Signed-off-by: Sumit Garg <sumit.garg@...aro.org>
> > ---
> >  .../ABI/testing/sysfs-bus-optee-devices         |  9 +++++++++
> >  drivers/tee/optee/device.c                      | 17 +++++++++++++++--
> >  2 files changed, 24 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > index 0f58701367b6..d914f6629662 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-optee-devices
> > +++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > @@ -6,3 +6,12 @@ Description:
> >                 OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
> >                 matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
> >                 are free to create needed API under optee-ta-<uuid> directory.
> > +
> > +What:          /sys/bus/tee/devices/optee-ta-<uuid>/need_supplicant
> > +Date:          July 2008
>
> nit, date needs changing
>

Thanks for catching that. If nothing major comes up then I hope Jens
can correct it while applying.

> > +KernelVersion: 6.7
> > +Contact:       op-tee@...ts.trustedfirmware.org
> > +Description:
> > +               Allows to distinguish whether an OP-TEE based TA/device requires user-space
> > +               tee-supplicant to function properly or not. This attribute will be present for
> > +               devices which depend on tee-supplicant to be running.
> > diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> > index 64f0e047c23d..4b1092127694 100644
> > --- a/drivers/tee/optee/device.c
> > +++ b/drivers/tee/optee/device.c
> > @@ -60,7 +60,16 @@ static void optee_release_device(struct device *dev)
> >         kfree(optee_device);
> >  }
> >
> > -static int optee_register_device(const uuid_t *device_uuid)
> > +static ssize_t
>
> (struct device *dev,
> > +                                   struct device_attribute *attr,
> > +                                   char *buf)
> > +{
> > +       return 0;
> > +}
> > +
> > +static DEVICE_ATTR_RO(need_supplicant);
> > +
> > +static int optee_register_device(const uuid_t *device_uuid, u32 func)
> >  {
> >         struct tee_client_device *optee_device = NULL;
> >         int rc;
> > @@ -83,6 +92,10 @@ static int optee_register_device(const uuid_t *device_uuid)
> >                 put_device(&optee_device->dev);
> >         }
> >
> > +       if (func == PTA_CMD_GET_DEVICES_SUPP)
> > +               device_create_file(&optee_device->dev,
> > +                                  &dev_attr_need_supplicant);
> > +
> >         return rc;
> >  }
> >
> > @@ -142,7 +155,7 @@ static int __optee_enumerate_devices(u32 func)
> >         num_devices = shm_size / sizeof(uuid_t);
> >
> >         for (idx = 0; idx < num_devices; idx++) {
> > -               rc = optee_register_device(&device_uuid[idx]);
> > +               rc = optee_register_device(&device_uuid[idx], func);
> >                 if (rc)
> >                         goto out_shm;
> >         }
> > --
> > 2.34.1
> >
>
> Other than that
> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>

Thanks.

-Sumit