Re: [PATCH v6 1/5] tee: add sec_world_id to struct tee_shm

[Jens Wiklander <jens.wiklander@linaro.org>]

On Wed, Oct 06, 2021 at 10:36:22AM +0200, Jerome Forissier wrote:
> 
> 
> On 10/6/21 9:08 AM, Jens Wiklander wrote:
> > Adds sec_world_id to struct tee_shm which describes a shared memory
> > object. sec_world_id can be used by a driver to store an id assigned by
> > secure world.
> > 
> > Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
> > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> > ---
> >  include/linux/tee_drv.h | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> > index 3ebfea0781f1..a1f03461369b 100644
> > --- a/include/linux/tee_drv.h
> > +++ b/include/linux/tee_drv.h
> > @@ -197,7 +197,11 @@ int tee_session_calc_client_uuid(uuid_t *uuid, u32 connection_method,
> >   * @num_pages:	number of locked pages
> >   * @dmabuf:	dmabuf used to for exporting to user space
> >   * @flags:	defined by TEE_SHM_* in tee_drv.h
> > - * @id:		unique id of a shared memory object on this device
> > + * @id:		unique id of a shared memory object on this device, shared
> > + *		with user space
> > + * @sec_world_id:
> > + *		secure world assigned id of this shared memory object, not
> > + *		used by all drivers
> >   *
> >   * This pool is only supposed to be accessed directly from the TEE
> >   * subsystem and from drivers that implements their own shm pool manager.
> > @@ -213,6 +217,7 @@ struct tee_shm {
> >  	struct dma_buf *dmabuf;
> >  	u32 flags;
> >  	int id;
> > +	u64 sec_world_id;
> 
> Wouldn't it make more sense to have this outside struct tee_shm in a
> driver-specific struct? (which could always be obtained from a struct
> tee_shm * using container_of() for example).

Yes, that could be quite useful, but the problem is that it's
tee_shm_alloc() that allocates this struct so it can't easily be
embedded in a driver-specific struct.

We could of course change that but that will require changes to the
AMDTEE driver also. I'm not sure it's worth the trouble though, since
the AMDTEE driver could make use of this field too.

Cheers,
Jens