Re: [PATCH v2 09/12] tee: add tee_shm_register_{user,kernel}_buf()

[Jens Wiklander]

On Thu, Jan 20, 2022 at 12:00 PM Sumit Garg <sumit.garg@xxxxxxxxxx> wrote:
>
> On Fri, 14 Jan 2022 at 20:38, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
> >
> > Adds the two new functions tee_shm_register_user_buf() and
> > tee_shm_register_kernel_buf() which should be used instead of the old
> > tee_shm_register().
> >
> > This avoids having the caller supplying the flags parameter which
> > exposes a bit more than desired of the internals of the TEE subsystem.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> >  drivers/tee/tee_core.c  |  3 +--
> >  drivers/tee/tee_shm.c   | 34 ++++++++++++++++++++++++++++++++++
> >  include/linux/tee_drv.h |  4 ++++
> >  3 files changed, 39 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> > index a15812baaeb1..8aa1a4836b92 100644
> > --- a/drivers/tee/tee_core.c
> > +++ b/drivers/tee/tee_core.c
> > @@ -334,8 +334,7 @@ tee_ioctl_shm_register(struct tee_context *ctx,
> >         if (data.flags)
> >                 return -EINVAL;
> >
> > -       shm = tee_shm_register(ctx, data.addr, data.length,
> > -                              TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
> > +       shm = tee_shm_register_user_buf(ctx, data.addr, data.length);
> >         if (IS_ERR(shm))
> >                 return PTR_ERR(shm);
> >
> > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> > index d51bf97ce7e5..6a1dbce75616 100644
> > --- a/drivers/tee/tee_shm.c
> > +++ b/drivers/tee/tee_shm.c
> > @@ -301,6 +301,40 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
> >  }
> >  EXPORT_SYMBOL_GPL(tee_shm_register);
> >
> > +/**
> > + * tee_shm_register_user_buf() - Register a userspace shared memory buffer
> > + * @ctx:       Context that registers the shared memory
> > + * @addr:      The userspace address of the shared buffer
> > + * @length:    Length of the shared buffer
> > + *
> > + * @returns a pointer to 'struct tee_shm'
> > + */
> > +struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
> > +                                         unsigned long addr, size_t length)
> > +{
> > +       return tee_shm_register(ctx, addr, length,
> > +                               TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
> > +}
> > +EXPORT_SYMBOL_GPL(tee_shm_register_user_buf);
> > +
>
> Similar comment as for tee_shm_alloc_user_buf() in patch #3. This
> isn't required to be exported but rather a private function to TEE
> core.

OK, I'll fix it in v3.

Thanks,
Jens

>
> -Sumit
>
> > +/**
> > + * tee_shm_register_kernel_buf() - Register kernel memory to be shared with
> > + *                                secure world
> > + * @ctx:       Context that registers the shared memory
> > + * @addr:      The buffer
> > + * @length:    Length of the buffer
> > + *
> > + * @returns a pointer to 'struct tee_shm'
> > + */
> > +
> > +struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
> > +                                           void *addr, size_t length)
> > +{
> > +       return tee_shm_register(ctx, (unsigned long)addr, length,
> > +                               TEE_SHM_DMA_BUF | TEE_SHM_KERNEL_MAPPED);
> > +}
> > +EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
> > +
> >  static int tee_shm_fop_release(struct inode *inode, struct file *filp)
> >  {
> >         tee_shm_put(filp->private_data);
> > diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> > index e71cb0411e9c..029c9a0590cc 100644
> > --- a/include/linux/tee_drv.h
> > +++ b/include/linux/tee_drv.h
> > @@ -289,6 +289,10 @@ struct tee_shm *tee_shm_alloc_kernel_buf(struct tee_context *ctx, size_t size);
> >   */
> >  struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
> >                                  size_t length, u32 flags);
> > +struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
> > +                                         unsigned long addr, size_t length);
> > +struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
> > +                                           void *addr, size_t length);
> >
> >  /**
> >   * tee_shm_is_registered() - Check if shared memory object in registered in TEE
> > --
> > 2.31.1
> >