On Tue, Jun 17, 2025 at 1:32 PM Sumit Garg sumit.garg@kernel.org wrote:

On Tue, Jun 10, 2025 at 03:13:50PM +0200, Jens Wiklander wrote:

...

Add tee_shm_alloc_dma_mem() to allocate DMA memory. The memory is represented by a tee_shm object using the new flag TEE_SHM_DMA_MEM to identify it as DMA memory. The allocated memory will later be lent to the TEE to be used as protected memory.

Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

drivers/tee/tee_shm.c | 85 +++++++++++++++++++++++++++++++++++++++- include/linux/tee_core.h | 5 +++ 2 files changed, 88 insertions(+), 2 deletions(-)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c index e63095e84644..60b0f3932cee 100644 --- a/drivers/tee/tee_shm.c +++ b/drivers/tee/tee_shm.c @@ -5,6 +5,8 @@ #include <linux/anon_inodes.h> #include <linux/device.h> #include <linux/dma-buf.h> +#include <linux/dma-mapping.h> +#include <linux/highmem.h> #include <linux/idr.h> #include <linux/io.h> #include <linux/mm.h> @@ -13,9 +15,14 @@ #include <linux/tee_core.h> #include <linux/uaccess.h> #include <linux/uio.h> -#include <linux/highmem.h> #include "tee_private.h"

+struct tee_shm_dma_mem {

• struct tee_shm shm;
  

• dma_addr_t dma_addr;
  

• struct page *page;
  

+};

static void shm_put_kernel_pages(struct page **pages, size_t page_count) { size_t n; @@ -48,7 +55,16 @@ static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm) { void *p = shm;

• if (shm->flags & TEE_SHM_DMA_BUF) {
  

• if (shm->flags & TEE_SHM_DMA_MEM) {
  

+#if IS_ENABLED(CONFIG_TEE_DMABUF_HEAPS)

nit: this config check can be merged into the above if check.

No, because dma_free_pages() is only defined if CONFIG_TEE_DMABUF_HEAPS is enabled.

...

•         struct tee_shm_dma_mem *dma_mem;
  

•         dma_mem = container_of(shm, struct tee_shm_dma_mem, shm);
  

•         p = dma_mem;
  

•         dma_free_pages(&teedev->dev, shm->size, dma_mem->page,
  

•                        dma_mem->dma_addr, DMA_BIDIRECTIONAL);
  

+#endif

• } else if (shm->flags & TEE_SHM_DMA_BUF) {
  

Do we need a similar config check for this flag too?

No, because DMA_SHARED_BUFFER is selected, so the dma_buf functions are defined.

Cheers, Jens

With these addressed, feel free to add:

Reviewed-by: Sumit Garg sumit.garg@oss.qualcomm.com

-Sumit

...

          struct tee_shm_dmabuf_ref *ref;

          ref = container_of(shm, struct tee_shm_dmabuf_ref, shm);

@@ -303,6 +319,71 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size) } EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);

+#if IS_ENABLED(CONFIG_TEE_DMABUF_HEAPS) +/**

• • tee_shm_alloc_dma_mem() - Allocate DMA memory as shared memory object
• • @ctx: Context that allocates the shared memory
• • @page_count: Number of pages
• • The allocated memory is expected to be lent (made inaccessible to the
• • kernel) to the TEE while it's used and returned (accessible to the
• • kernel again) before it's freed.
• • This function should normally only be used internally in the TEE
• • drivers.
• • @returns a pointer to 'struct tee_shm'
• */

+struct tee_shm *tee_shm_alloc_dma_mem(struct tee_context *ctx,

•                               size_t page_count)
  

+{

• struct tee_device *teedev = ctx->teedev;
  

• struct tee_shm_dma_mem *dma_mem;
  

• dma_addr_t dma_addr;
  

• struct page *page;
  

• if (!tee_device_get(teedev))
  

•         return ERR_PTR(-EINVAL);
  

• page = dma_alloc_pages(&teedev->dev, page_count * PAGE_SIZE,
  

•                        &dma_addr, DMA_BIDIRECTIONAL, GFP_KERNEL);
  

• if (!page)
  

•         goto err_put_teedev;
  

• dma_mem = kzalloc(sizeof(*dma_mem), GFP_KERNEL);
  

• if (!dma_mem)
  

•         goto err_free_pages;
  

• refcount_set(&dma_mem->shm.refcount, 1);
  

• dma_mem->shm.ctx = ctx;
  

• dma_mem->shm.paddr = page_to_phys(page);
  

• dma_mem->dma_addr = dma_addr;
  

• dma_mem->page = page;
  

• dma_mem->shm.size = page_count * PAGE_SIZE;
  

• dma_mem->shm.flags = TEE_SHM_DMA_MEM;
  

• teedev_ctx_get(ctx);
  

• return &dma_mem->shm;
  

+err_free_pages:

• dma_free_pages(&teedev->dev, page_count * PAGE_SIZE, page, dma_addr,
  

•                DMA_BIDIRECTIONAL);
  

+err_put_teedev:

• tee_device_put(teedev);
  

• return ERR_PTR(-ENOMEM);
  

+} +EXPORT_SYMBOL_GPL(tee_shm_alloc_dma_mem); +#else +struct tee_shm *tee_shm_alloc_dma_mem(struct tee_context *ctx,

•                               size_t page_count)
  

+{

• return ERR_PTR(-EINVAL);
  

+} +EXPORT_SYMBOL_GPL(tee_shm_alloc_dma_mem); +#endif

int tee_dyn_shm_alloc_helper(struct tee_shm *shm, size_t size, size_t align, int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm, diff --git a/include/linux/tee_core.h b/include/linux/tee_core.h index f17710196c4c..e46a53e753af 100644 --- a/include/linux/tee_core.h +++ b/include/linux/tee_core.h @@ -29,6 +29,8 @@ #define TEE_SHM_POOL BIT(2) /* Memory allocated from pool */ #define TEE_SHM_PRIV BIT(3) /* Memory private to TEE driver */ #define TEE_SHM_DMA_BUF BIT(4) /* Memory with dma-buf handle */ +#define TEE_SHM_DMA_MEM BIT(5) /* Memory allocated with */

•                                 /* dma_alloc_pages() */
  
  

#define TEE_DEVICE_FLAG_REGISTERED 0x1 #define TEE_MAX_DEV_NAME_LEN 32 @@ -310,6 +312,9 @@ void *tee_get_drvdata(struct tee_device *teedev); */ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size);

+struct tee_shm *tee_shm_alloc_dma_mem(struct tee_context *ctx,

•                               size_t page_count);
  

int tee_dyn_shm_alloc_helper(struct tee_shm *shm, size_t size, size_t align, int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm, -- 2.43.0