Hi,
On Mon, Sep 08, 2025 at 03:35:02PM +0800, 戴睿 wrote:
Hi OP-TEE maintainers,
I found an issue in optee_os related to FFA memory handling across different kernel page sizes.
File: core/arch/arm/mm/mobj_ffa.c Function: mobj_ffa_get_by_cookie()
At the beginning of this function there is a check:
if (internal_offs >= SMALL_PAGE_SIZE) return NULL;
Here, SMALL_PAGE_SIZE is fixed to 4KB. When running with a Linux kernel built with 16K or 64K page sizes (CONFIG_ARM64_16K_PAGES or CONFIG_ARM64_64K_PAGES), this check incorrectly rejects valid offsets. As a result, mobj_ffa_get_by_cookie() returns NULL, which leads to TEE_ERROR_BAD_PARAMETERS during FFA communication (for example when set_fmem_param() calls it).
Impact:
- FFA communication fails on systems where the kernel uses 16K or 64K pages.
- With 16K becoming more widely adopted (e.g. Google’s standardization), this problem will be more common.
Expected behavior: The function should not assume a fixed 4K page size, but adapt to the actual kernel page size.
Environment:
- OP-TEE version: observed in multiple versions including latest master
- Platform: ARM64 with FFA enabled
- Kernel config: CONFIG_ARM64_16K_PAGES / CONFIG_ARM64_64K_PAGES
Possible fix:
- Replace the SMALL_PAGE_SIZE check with a dynamic check based on the kernel’s actual page size,
or make the validation configurable.
I don't think it is an OP-TEE bug as of now but a missing feature in OP-TEE to support 16K and 64K pages. Would you be able to enable this feature for OP-TEE?
-Sumit
Please let me know if you need more details. I am happy to test or provide a patch suggestion if that helps.
Best regards, ddrdtdn