Re: [PATCH v3 1/2] optee: add page list to kernel private shared memory

[Sumit Garg]

On Tue, 14 Nov 2023 at 15:22, Jens Wiklander <jens.wiklander@xxxxxxxxxx> wrote:
>
> Until now has kernel private shared memory allocated as dynamic shared
> memory (not from the static shared memory pool) been returned without a
> list of physical pages on allocations via RPC. To support allocations
> larger than one page add a list of physical pages.

Although this patch looks like a good cleanup, I can't find an ABI
change here. Wasn't a list of pages returned earlier too?

-Sumit

>
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
>  drivers/tee/optee/core.c    | 28 +++++++++++++----------
>  drivers/tee/optee/smc_abi.c | 45 +++++++++++++++++--------------------
>  2 files changed, 37 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> index 2a258bd3b6b5..38ea2fecfc2e 100644
> --- a/drivers/tee/optee/core.c
> +++ b/drivers/tee/optee/core.c
> @@ -27,7 +27,10 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
>                                                    unsigned long start))
>  {
>         unsigned int order = get_order(size);
> +       unsigned int nr_pages = 1 << order;
> +       struct page **pages;
>         struct page *page;
> +       unsigned int i;
>         int rc = 0;
>
>         /*
> @@ -42,30 +45,29 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
>         shm->paddr = page_to_phys(page);
>         shm->size = PAGE_SIZE << order;
>
> -       if (shm_register) {
> -               unsigned int nr_pages = 1 << order, i;
> -               struct page **pages;
> +       pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
> +       if (!pages) {
> +               rc = -ENOMEM;
> +               goto err;
> +       }
>
> -               pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
> -               if (!pages) {
> -                       rc = -ENOMEM;
> -                       goto err;
> -               }
> +       for (i = 0; i < nr_pages; i++)
> +               pages[i] = page + i;
>
> -               for (i = 0; i < nr_pages; i++)
> -                       pages[i] = page + i;
> +       shm->pages = pages;
> +       shm->num_pages = nr_pages;
>
> +       if (shm_register) {
>                 rc = shm_register(shm->ctx, shm, pages, nr_pages,
>                                   (unsigned long)shm->kaddr);
> -               kfree(pages);
>                 if (rc)
>                         goto err;
>         }
>
>         return 0;
> -
>  err:
>         free_pages((unsigned long)shm->kaddr, order);
> +       shm->kaddr = NULL;
>         return rc;
>  }
>
> @@ -77,6 +79,8 @@ void optee_pool_op_free_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
>                 shm_unregister(shm->ctx, shm);
>         free_pages((unsigned long)shm->kaddr, get_order(shm->size));
>         shm->kaddr = NULL;
> +       kfree(shm->pages);
> +       shm->pages = NULL;
>  }
>
>  static void optee_bus_scan(struct work_struct *work)
> diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> index d5b28fd35d66..b69410c7cc0a 100644
> --- a/drivers/tee/optee/smc_abi.c
> +++ b/drivers/tee/optee/smc_abi.c
> @@ -678,10 +678,11 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
>                                           struct optee_msg_arg *arg,
>                                           struct optee_call_ctx *call_ctx)
>  {
> -       phys_addr_t pa;
>         struct tee_shm *shm;
>         size_t sz;
>         size_t n;
> +       struct page **pages;
> +       size_t page_count;
>
>         arg->ret_origin = TEEC_ORIGIN_COMMS;
>
> @@ -716,32 +717,23 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
>                 return;
>         }
>
> -       if (tee_shm_get_pa(shm, 0, &pa)) {
> -               arg->ret = TEEC_ERROR_BAD_PARAMETERS;
> -               goto bad;
> -       }
> -
> -       sz = tee_shm_get_size(shm);
> -
> -       if (tee_shm_is_dynamic(shm)) {
> -               struct page **pages;
> +       /*
> +        * If there are pages it's dynamically allocated shared memory (not
> +        * from the reserved shared memory pool) and needs to be
> +        * registered.
> +        */
> +       pages = tee_shm_get_pages(shm, &page_count);
> +       if (pages) {
>                 u64 *pages_list;
> -               size_t page_num;
> -
> -               pages = tee_shm_get_pages(shm, &page_num);
> -               if (!pages || !page_num) {
> -                       arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
> -                       goto bad;
> -               }
>
> -               pages_list = optee_allocate_pages_list(page_num);
> +               pages_list = optee_allocate_pages_list(page_count);
>                 if (!pages_list) {
>                         arg->ret = TEEC_ERROR_OUT_OF_MEMORY;
>                         goto bad;
>                 }
>
>                 call_ctx->pages_list = pages_list;
> -               call_ctx->num_entries = page_num;
> +               call_ctx->num_entries = page_count;
>
>                 arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
>                                       OPTEE_MSG_ATTR_NONCONTIG;
> @@ -752,17 +744,22 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
>                 arg->params[0].u.tmem.buf_ptr = virt_to_phys(pages_list) |
>                         (tee_shm_get_page_offset(shm) &
>                          (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));
> -               arg->params[0].u.tmem.size = tee_shm_get_size(shm);
> -               arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
>
> -               optee_fill_pages_list(pages_list, pages, page_num,
> +               optee_fill_pages_list(pages_list, pages, page_count,
>                                       tee_shm_get_page_offset(shm));
>         } else {
> +               phys_addr_t pa;
> +
> +               if (tee_shm_get_pa(shm, 0, &pa)) {
> +                       arg->ret = TEEC_ERROR_BAD_PARAMETERS;
> +                       goto bad;
> +               }
> +
>                 arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT;
>                 arg->params[0].u.tmem.buf_ptr = pa;
> -               arg->params[0].u.tmem.size = sz;
> -               arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
>         }
> +       arg->params[0].u.tmem.size = tee_shm_get_size(shm);
> +       arg->params[0].u.tmem.shm_ref = (unsigned long)shm;
>
>         arg->ret = TEEC_SUCCESS;
>         return;
> --
> 2.34.1
>