Messages in this thread | | | From | Sumit Garg <> | Date | Wed, 24 May 2023 13:26:18 +0530 | Subject | Re: [PATCH v4 0/3] introduce tee-based EFI Runtime Variable Service |
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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 >
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