lkml.org 
[lkml]   [2023]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v4 0/3] introduce tee-based EFI Runtime Variable Service
On Tue, 23 May 2023 at 14:36, Masahisa Kojima
<masahisa.kojima@linaro.org> wrote:
>
> This series introduces the tee based EFI Runtime Variable Service.
>
> The eMMC device is typically owned by the non-secure world(linux in
> this case). There is an existing solution utilizing eMMC RPMB partition
> for EFI Variables, it is implemented by interacting with
> OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver
> and tee-supplicant. The last piece is the tee-based variable access
> driver to interact with OP-TEE and StandaloneMM.
>
> Changelog:
> v3 -> v4:
> - replace the reference from EDK2 to PI Specification
> - remove EDK2 source code reference comments
> - prepare nonblocking variant of set_variable, it just returns
> EFI_UNSUPPORTED
> - remove redundant buffer size check
> - argument name change in mm_communicate
> - function interface changes in setup_mm_hdr to remove (void **) cast

I don't have detailed insights into how EFI spec mandates StandaloneMM
should be implemented. But utilizing OP-TEE as the underlying
transport here looks fine to me. FWIW,

For the series:
Acked-by: Sumit Garg <sumit.garg@linaro.org>

-Sumit

>
> v2 -> v3:
> - add CONFIG_EFI dependency to TEE_STMM_EFI
> - add missing return code check for tee_client_invoke_func()
> - directly call efivars_register/unregister from tee_stmm_efi.c
>
> rfc v1 -> v2:
> - split patch into three patches, one for drivers/tee,
> one for include/linux/efi.h, and one for the driver/firmware/efi/stmm
> - context/session management into probe() and remove() same as other tee
> client driver
> - StMM variable driver is moved from driver/tee/optee to driver/firmware/efi
> - use "tee" prefix instead of "optee" in driver/firmware/efi/stmm/tee_stmm_efi.c,
> this file does not contain op-tee specific code, abstracted by tee layer and
> StMM variable driver will work on other tee implementation.
> - PTA_STMM_CMD_COMMUNICATE -> PTA_STMM_CMD_COMMUNICATE
> - implement query_variable_store() but currently not used
> - no use of TEEC_SUCCESS, it is defined in driver/tee/optee/optee_private.h.
> Other tee client drivers use 0 instead of using TEEC_SUCCESS
> - remove TEEC_ERROR_EXCESS_DATA status, it is referred just to output
> error message
>
> Masahisa Kojima (3):
> efi: expose efivar generic ops register function
> efi: Add EFI_ACCESS_DENIED status code
> efi: Add tee-based EFI variable driver
>
> drivers/firmware/efi/Kconfig | 15 +
> drivers/firmware/efi/Makefile | 1 +
> drivers/firmware/efi/efi.c | 12 +
> drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++
> drivers/firmware/efi/stmm/tee_stmm_efi.c | 637 +++++++++++++++++++
> include/linux/efi.h | 4 +
> 6 files changed, 905 insertions(+)
> create mode 100644 drivers/firmware/efi/stmm/mm_communication.h
> create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c
>
> --
> 2.30.2
>

\
 
 \ /
  Last update: 2023-05-24 09:58    [W:1.553 / U:0.820 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site