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

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

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
>

Hi Sumit,

On Wed, 24 May 2023 at 10:56, Sumit Garg <sumit.garg@linaro.org> wrote:
>
> 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>

Thanks!

 FWIW the PI spec describes some of the functionality and how that
should be accessed.
There's a EFI_MM_COMMUNICATION_PROTOCOL which is not used here.
Instead the entry point is via an SMC to op-tee and the payload
adheres to what the PI spec describes in its EFI_MM_COMMUNICATE_HEADER

Regards
/Ilias
>
> -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
> >

On Wed, 24 May 2023 at 10:01, Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> Hi Sumit,
>
> On Wed, 24 May 2023 at 10:56, Sumit Garg <sumit.garg@linaro.org> wrote:
> >
> > 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>
>
> Thanks!
>
>  FWIW the PI spec describes some of the functionality and how that
> should be accessed.
> There's a EFI_MM_COMMUNICATION_PROTOCOL which is not used here.
> Instead the entry point is via an SMC to op-tee and the payload
> adheres to what the PI spec describes in its EFI_MM_COMMUNICATE_HEADER
>

Thanks for the resend

Could you please double check whether this needs any changes in
relation to this patch?

https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git/commit/?id=d86ff3333cb1d5f4

Hi Ard,

On Fri, 26 May 2023 at 01:11, Ard Biesheuvel <ardb@kernel.org> wrote:
>
> On Wed, 24 May 2023 at 10:01, Ilias Apalodimas
> <ilias.apalodimas@linaro.org> wrote:
> >
> > Hi Sumit,
> >
> > On Wed, 24 May 2023 at 10:56, Sumit Garg <sumit.garg@linaro.org> wrote:
> > >
> > > 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>
> >
> > Thanks!
> >
> >  FWIW the PI spec describes some of the functionality and how that
> > should be accessed.
> > There's a EFI_MM_COMMUNICATION_PROTOCOL which is not used here.
> > Instead the entry point is via an SMC to op-tee and the payload
> > adheres to what the PI spec describes in its EFI_MM_COMMUNICATE_HEADER
> >
>
> Thanks for the resend
>
> Could you please double check whether this needs any changes in
> relation to this patch?
>
> https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git/commit/?id=d86ff3333cb1d5f4

I need to set a tee-based query_variable_info().
I will rebase to efi-next and send an updated version.

Thanks,
Masahisa Kojima