Re: [PATCH v8 0/5] introduce tee-based EFI Runtime Variable Service

[Ilias Apalodimas]

Hi Jan,

On Mon, 7 Aug 2023 at 05:53, Masahisa Kojima <masahisa.kojima@xxxxxxxxxx> 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:
> v7 -> v8
> Only patch #3 "efi: Add tee-based EFI variable driver" is updated.
> - fix typos
> - refactor error handling, direct return if applicable
> - use devm_add_action_or_reset() for closing of tee context/session
> - remove obvious comment

Any chance you can run this and see if it solves your issues?

Thanks
/Ilias
>
> v6 -> v7
> Patch #1-#4 are not updated.
> Patch #5 is added into this series, original patch is here:
> https://lore.kernel.org/all/20230609094532.562934-1-ilias.apalodimas@xxxxxxxxxx/
>
> There are two issues in the v6 series and v7 series addresses those.
>
> 1) efivar ops is not restored when the tee-supplicant daemon terminates.
>  -> As the following patch says, user must remove the device before
>     terminating tee-supplicant daemon.
>     https://lore.kernel.org/all/20230728134832.326467-1-sumit.garg@xxxxxxxxxx/
>
> 2) cause panic when someone remounts the efivarfs as RW even if
> SetVariable is not supported
>  -> The fifth patch addresses this issue.
>    "[PATCH v7 5/5] efivarfs: force RO when remounting if SetVariable is
>     not supported"
>
> v5 -> v6
> - new patch #4 is added in this series, #1-#3 patches are unchanged.
>   automatically update super block flag when the efivarops support
>   SetVariable runtime service, so that user does not need to manually
>   remount the efivarfs as RW.
>
> v4 -> v5
> - rebase to efi-next based on v6.4-rc1
> - set generic_ops.query_variable_info, it works as expected as follows.
> $ df -h /sys/firmware/efi/efivars/
> Filesystem      Size  Used Avail Use% Mounted on
> efivarfs         16K  1.3K   15K   8% /sys/firmware/efi/efivars
>
> 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
>
> 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
>
>
>
> Ilias Apalodimas (1):
>   efivarfs: force RO when remounting if SetVariable is not supported
>
> Masahisa Kojima (4):
>   efi: expose efivar generic ops register function
>   efi: Add EFI_ACCESS_DENIED status code
>   efi: Add tee-based EFI variable driver
>   efivarfs: automatically update super block flag
>
>  drivers/firmware/efi/Kconfig                 |  15 +
>  drivers/firmware/efi/Makefile                |   1 +
>  drivers/firmware/efi/efi.c                   |  18 +
>  drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++
>  drivers/firmware/efi/stmm/tee_stmm_efi.c     | 612 +++++++++++++++++++
>  drivers/firmware/efi/vars.c                  |   8 +
>  fs/efivarfs/super.c                          |  45 ++
>  include/linux/efi.h                          |  12 +
>  8 files changed, 947 insertions(+)
>  create mode 100644 drivers/firmware/efi/stmm/mm_communication.h
>  create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c
>
>
> base-commit: f6e6e95ce16205025b7b8680a66c30a0c4ec2270
> --
> 2.30.2
>