Re: [PATCH v2 1/2] optee: add page list to kernel private shared memory
From: Jens Wiklander
Date: Mon Nov 13 2023 - 12:13:53 EST
Hi Sumit,
On Fri, Nov 10, 2023 at 3:36 PM Sumit Garg <sumit.garg@xxxxxxxxxx> wrote:
>
> Hi Jens,
>
> On Wed, 8 Nov 2023 at 15:57, 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 for all allocations
> > larger than one page.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> > drivers/tee/optee/core.c | 40 +++++++++++++++++++++++++--------
> > drivers/tee/optee/smc_abi.c | 45 +++++++++++++++++--------------------
> > 2 files changed, 52 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > index 2a258bd3b6b5..a425eca0173d 100644
> > --- a/drivers/tee/optee/core.c
> > +++ b/drivers/tee/optee/core.c
> > @@ -27,6 +27,7 @@ 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 *page;
> > int rc = 0;
> >
> > @@ -39,12 +40,24 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
> > return -ENOMEM;
> >
> > shm->kaddr = page_address(page);
> > - shm->paddr = page_to_phys(page);
> > shm->size = PAGE_SIZE << order;
> >
> > - if (shm_register) {
> > - unsigned int nr_pages = 1 << order, i;
> > + /*
> > + * If memory is registered immediately use a temporary page list
> > + * and free it directly after the registration is completed.
> > + *
> > + * Else, if we have allocated more than one page store a page
> > + * list in the struct tee_shm.
> > + *
> > + * Else, store the physical address of the single page that was
> > + * allocated.
> > + *
> > + * optee_pool_op_free_helper() is responsible for freeing the
> > + * resourses allocated in this function.
> > + */
>
> It looks a bit complex to me. Do we really need it to be conditional?
> I was thinking if we can simplify this API as follows:
>
> int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
> size_t size, size_t align,
> int (*shm_register)(struct tee_shm *shm))
> {
> unsigned int order = get_order(size);
> unsigned int nr_pages = 1 << order, i;
> struct page **pages;
> struct page *page;
> int rc = 0;
>
> /*
> * Ignore alignment since this is already going to be page aligned
> * and there's no need for any larger alignment.
> */
> page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> if (!page)
> return -ENOMEM;
>
> shm->kaddr = page_address(page);
> shm->paddr = page_to_phys(page);
> shm->size = PAGE_SIZE << order;
>
> 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;
>
> shm->pages = pages;
> shm->num_pages = nr_pages;
>
> if (shm_register) {
> rc = shm_register(shm);
> if (rc)
> goto err;
> }
>
> return 0;
>
> err:
> kfree(pages);
> free_pages((unsigned long)shm->kaddr, order);
> return rc;
> }
Good idea, I'll try it in the v3.
Thanks,
Jens
>
> -Sumit
>
> > + if (shm_register || nr_pages > 1) {
> > struct page **pages;
> > + unsigned int i;
> >
> > pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
> > if (!pages) {
> > @@ -55,17 +68,24 @@ int optee_pool_op_alloc_helper(struct tee_shm_pool *pool, struct tee_shm *shm,
> > for (i = 0; i < nr_pages; i++)
> > pages[i] = page + i;
> >
> > - rc = shm_register(shm->ctx, shm, pages, nr_pages,
> > - (unsigned long)shm->kaddr);
> > - kfree(pages);
> > - if (rc)
> > - goto err;
> > + if (shm_register) {
> > + rc = shm_register(shm->ctx, shm, pages, nr_pages,
> > + (unsigned long)shm->kaddr);
> > + kfree(pages);
> > + if (rc)
> > + goto err;
> > + } else {
> > + shm->pages = pages;
> > + shm->num_pages = nr_pages;
> > + }
> > + } else {
> > + shm->paddr = page_to_phys(page);
> > }
> >
> > return 0;
> > -
> > err:
> > free_pages((unsigned long)shm->kaddr, order);
> > + shm->kaddr = NULL;
> > return rc;
> > }
> >
> > @@ -77,6 +97,8 @@ 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
> >