Hi Tyler, On Wed, 9 Jun 2021 at 05:55, Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx> wrote: > > Uncouple the registration of dynamic shared memory buffers from the > TEE_SHM_DMA_BUF flag. Drivers may wish to allocate dynamic shared memory > regions but do not need them to be backed by a dma-buf when the memory > region is private to the driver. In this case drivers should use tee_shm_register() instead where the memory allocated is actually private to the driver. However, you need to remove TEE_SHM_DMA_BUF as a mandatory flag for tee_shm_register(). Have a look at an example here [1]. So modifying tee_shm_alloc() for this purpose doesn't look appropriate to me. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/security/keys/trusted-keys/trusted_tee.c#n73 -Sumit > > Allow callers of tee_shm_alloc() to specify the TEE_SHM_REGISTER flag to > request registration. If the TEE implementation does not require dynamic > shared memory to be registered, clear the flag prior to calling the > corresponding pool alloc function. Update the OP-TEE driver to respect > TEE_SHM_REGISTER, rather than TEE_SHM_DMA_BUF, when deciding whether to > (un)register on alloc/free operations. The AMD-TEE driver continues to > ignore the TEE_SHM_REGISTER flag. > > Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx> > --- > drivers/tee/optee/shm_pool.c | 5 ++--- > drivers/tee/tee_shm.c | 11 ++++++++++- > 2 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/drivers/tee/optee/shm_pool.c b/drivers/tee/optee/shm_pool.c > index da06ce9b9313..6054343a29fb 100644 > --- a/drivers/tee/optee/shm_pool.c > +++ b/drivers/tee/optee/shm_pool.c > @@ -27,7 +27,7 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > shm->paddr = page_to_phys(page); > shm->size = PAGE_SIZE << order; > > - if (shm->flags & TEE_SHM_DMA_BUF) { > + if (shm->flags & TEE_SHM_REGISTER) { > unsigned int nr_pages = 1 << order, i; > struct page **pages; > > @@ -42,7 +42,6 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > page++; > } > > - shm->flags |= TEE_SHM_REGISTER; > rc = optee_shm_register(shm->ctx, shm, pages, nr_pages, > (unsigned long)shm->kaddr); > kfree(pages); > @@ -60,7 +59,7 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm, > static void pool_op_free(struct tee_shm_pool_mgr *poolm, > struct tee_shm *shm) > { > - if (shm->flags & TEE_SHM_DMA_BUF) > + if (shm->flags & TEE_SHM_REGISTER) > optee_shm_unregister(shm->ctx, shm); > > free_pages((unsigned long)shm->kaddr, get_order(shm->size)); > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index 00472f5ce22e..1c0176550b9c 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -117,7 +117,7 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) > return ERR_PTR(-EINVAL); > } > > - if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF))) { > + if ((flags & ~(TEE_SHM_MAPPED | TEE_SHM_DMA_BUF | TEE_SHM_REGISTER))) { > dev_err(teedev->dev.parent, "invalid shm flags 0x%x", flags); > return ERR_PTR(-EINVAL); > } > @@ -137,6 +137,15 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) > goto err_dev_put; > } > > + if (!teedev->desc->ops->shm_register || > + !teedev->desc->ops->shm_unregister) { > + /* registration is not required by the TEE implementation */ > + flags &= ~TEE_SHM_REGISTER; > + } else if (flags & TEE_SHM_DMA_BUF) { > + /* all dma-buf backed shm allocations are registered */ > + flags |= TEE_SHM_REGISTER; > + } > + > shm->flags = flags | TEE_SHM_POOL; > shm->ctx = ctx; > if (flags & TEE_SHM_DMA_BUF) > -- > 2.25.1 >
