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[v4,0/6] TEE subsystem for restricted dma-buf allocations

Message ID 20241217100809.3962439-1-jens.wiklander@linaro.org (mailing list archive)
Headers show
Series TEE subsystem for restricted dma-buf allocations | expand

Message

Jens Wiklander Dec. 17, 2024, 10:07 a.m. UTC
Hi,

This patch set allocates the restricted DMA-bufs via the TEE subsystem.

The TEE subsystem handles the DMA-buf allocations since it is the TEE
(OP-TEE, AMD-TEE, TS-TEE, or perhaps a future QCOMTEE) which sets up the
restrictions for the memory used for the DMA-bufs.

I've added a new IOCTL, TEE_IOC_RSTMEM_ALLOC, to allocate the restricted
DMA-bufs. This IOCTL reaches the backend TEE driver, allowing it to choose
how to allocate the restricted physical memory.

TEE_IOC_RSTMEM_ALLOC takes in addition to a size and flags parameters also
a use-case parameter. This is used by the backend TEE driver to decide on
allocation policy and which devices should be able to access the memory.

Three use-cases (Secure Video Playback, Trusted UI, and Secure Video
Recording) has been identified so far to serve as examples of what can be
expected. More use-cases can be added in userspace ABI, but it's up to the
backend TEE drivers to provide the implementation.

Each use-case has it's own restricted memory pool since different use-cases
requires isolation from different parts of the system. A restricted memory
pool can be based on a static carveout instantiated while probing the TEE
backend driver, or dynamically allocated from CMA and made restricted as
needed by the TEE.

This can be tested on QEMU with the following steps:
repo init -u https://github.com/jenswi-linaro/manifest.git -m qemu_v8.xml \
        -b prototype/sdp-v4
repo sync -j8
cd build
make toolchains -j$(nproc)
make SPMC_AT_EL=1 all -j$(nproc)
make SPMC_AT_EL=1 run-only
# login and at the prompt:
xtest --sdp-basic

The SPMC_AT_EL=1 parameter configures the build with FF-A and an SPMC at
S-EL1 inside OP-TEE. The parameter can be changed into SPMC_AT_EL=n to test
without FF-A using the original SMC ABI instead. Please remember to do
%rm -rf ../trusted-firmware-a/build/qemu
for TF-A to be rebuilt properly using the new configuration.

https://optee.readthedocs.io/en/latest/building/prerequisites.html
list dependencies needed to build the above.

The tests are pretty basic, mostly checking that a Trusted Application in
the secure world can access and manipulate the memory. There are also some
negative tests for out of bounds buffers etc.

Thanks,
Jens

Changes since V3:
* Make the use_case and flags field in struct tee_shm u32's instead of
  u16's
* Add more description for TEE_IOC_RSTMEM_ALLOC in the header file
* Import namespace DMA_BUF in module tee, reported by lkp@intel.com
* Added a note in the commit message for "optee: account for direction
  while converting parameters" why it's needed
* Factor out dynamic restricted memory allocation from
  "optee: support restricted memory allocation" into two new commits
  "optee: FF-A: dynamic restricted memory allocation" and
  "optee: smc abi: dynamic restricted memory allocation"
* Guard CMA usage with #ifdef CONFIG_CMA, effectively disabling dynamic
  restricted memory allocate if CMA isn't configured

Changes since the V2 RFC:
* Based on v6.12
* Replaced the flags for SVP and Trusted UID memory with a u32 field with
  unique id for each use case
* Added dynamic allocation of restricted memory pools
* Added OP-TEE ABI both with and without FF-A for dynamic restricted memory
* Added support for FF-A with FFA_LEND

Changes since the V1 RFC:
* Based on v6.11
* Complete rewrite, replacing the restricted heap with TEE_IOC_RSTMEM_ALLOC

Changes since Olivier's post [2]:
* Based on Yong Wu's post [1] where much of dma-buf handling is done in
  the generic restricted heap
* Simplifications and cleanup
* New commit message for "dma-buf: heaps: add Linaro restricted dmabuf heap
  support"
* Replaced the word "secure" with "restricted" where applicable

Jens Wiklander (6):
  tee: add restricted memory allocation
  optee: account for direction while converting parameters
  optee: sync secure world ABI headers
  optee: support restricted memory allocation
  optee: FF-A: dynamic restricted memory allocation
  optee: smc abi: dynamic restricted memory allocation

 drivers/tee/Makefile              |   1 +
 drivers/tee/optee/Makefile        |   1 +
 drivers/tee/optee/call.c          |  10 +-
 drivers/tee/optee/core.c          |   1 +
 drivers/tee/optee/ffa_abi.c       | 178 +++++++++++++-
 drivers/tee/optee/optee_ffa.h     |  27 ++-
 drivers/tee/optee/optee_msg.h     |  65 ++++-
 drivers/tee/optee/optee_private.h |  75 ++++--
 drivers/tee/optee/optee_smc.h     |  71 +++++-
 drivers/tee/optee/rpc.c           |  31 ++-
 drivers/tee/optee/rstmem.c        | 388 ++++++++++++++++++++++++++++++
 drivers/tee/optee/smc_abi.c       | 213 ++++++++++++++--
 drivers/tee/tee_core.c            |  38 ++-
 drivers/tee/tee_private.h         |   2 +
 drivers/tee/tee_rstmem.c          | 201 ++++++++++++++++
 drivers/tee/tee_shm.c             |   2 +
 drivers/tee/tee_shm_pool.c        |  69 +++++-
 include/linux/tee_core.h          |  15 ++
 include/linux/tee_drv.h           |   2 +
 include/uapi/linux/tee.h          |  44 +++-
 20 files changed, 1358 insertions(+), 76 deletions(-)
 create mode 100644 drivers/tee/optee/rstmem.c
 create mode 100644 drivers/tee/tee_rstmem.c


base-commit: fac04efc5c793dccbd07e2d59af9f90b7fc0dca4

Comments

Simona Vetter Dec. 18, 2024, 11:06 a.m. UTC | #1
On Tue, Dec 17, 2024 at 11:07:36AM +0100, Jens Wiklander wrote:
> Hi,
> 
> This patch set allocates the restricted DMA-bufs via the TEE subsystem.
> 
> The TEE subsystem handles the DMA-buf allocations since it is the TEE
> (OP-TEE, AMD-TEE, TS-TEE, or perhaps a future QCOMTEE) which sets up the
> restrictions for the memory used for the DMA-bufs.
> 
> I've added a new IOCTL, TEE_IOC_RSTMEM_ALLOC, to allocate the restricted
> DMA-bufs. This IOCTL reaches the backend TEE driver, allowing it to choose
> how to allocate the restricted physical memory.
> 
> TEE_IOC_RSTMEM_ALLOC takes in addition to a size and flags parameters also
> a use-case parameter. This is used by the backend TEE driver to decide on
> allocation policy and which devices should be able to access the memory.
> 
> Three use-cases (Secure Video Playback, Trusted UI, and Secure Video
> Recording) has been identified so far to serve as examples of what can be
> expected. More use-cases can be added in userspace ABI, but it's up to the
> backend TEE drivers to provide the implementation.
> 
> Each use-case has it's own restricted memory pool since different use-cases
> requires isolation from different parts of the system. A restricted memory
> pool can be based on a static carveout instantiated while probing the TEE
> backend driver, or dynamically allocated from CMA and made restricted as
> needed by the TEE.
> 
> This can be tested on QEMU with the following steps:
> repo init -u https://github.com/jenswi-linaro/manifest.git -m qemu_v8.xml \
>         -b prototype/sdp-v4
> repo sync -j8
> cd build
> make toolchains -j$(nproc)
> make SPMC_AT_EL=1 all -j$(nproc)
> make SPMC_AT_EL=1 run-only
> # login and at the prompt:
> xtest --sdp-basic
> 
> The SPMC_AT_EL=1 parameter configures the build with FF-A and an SPMC at
> S-EL1 inside OP-TEE. The parameter can be changed into SPMC_AT_EL=n to test
> without FF-A using the original SMC ABI instead. Please remember to do
> %rm -rf ../trusted-firmware-a/build/qemu
> for TF-A to be rebuilt properly using the new configuration.
> 
> https://optee.readthedocs.io/en/latest/building/prerequisites.html
> list dependencies needed to build the above.
> 
> The tests are pretty basic, mostly checking that a Trusted Application in
> the secure world can access and manipulate the memory. There are also some
> negative tests for out of bounds buffers etc.

I think I've dropped this on earlier encrypted dma-buf discussions for
TEE, but can't find one right now ...

Do we have some open source userspace for this? To my knowledge we have
two implementations of encrypted/content protected dma-buf in upstream
right now in the amd and intel gpu drivers, and unless I'm mistaken they
both have some minimal userspace supporting EXT_protected_textures:

https://github.com/KhronosGroup/OpenGL-Registry/blob/main/extensions/EXT/EXT_protected_textures.txt

It's not great, but it does just barely clear the bar in my opinion. I
guess something in gstreamer or similar video pipeline framework would
also do the job.

Especially with the context of the uapi discussion in the v1/RFC thread I
think we need more than a bare-bones testcase to make sure this works in
actual use.

Cheers, Sima

> 
> Thanks,
> Jens
> 
> Changes since V3:
> * Make the use_case and flags field in struct tee_shm u32's instead of
>   u16's
> * Add more description for TEE_IOC_RSTMEM_ALLOC in the header file
> * Import namespace DMA_BUF in module tee, reported by lkp@intel.com
> * Added a note in the commit message for "optee: account for direction
>   while converting parameters" why it's needed
> * Factor out dynamic restricted memory allocation from
>   "optee: support restricted memory allocation" into two new commits
>   "optee: FF-A: dynamic restricted memory allocation" and
>   "optee: smc abi: dynamic restricted memory allocation"
> * Guard CMA usage with #ifdef CONFIG_CMA, effectively disabling dynamic
>   restricted memory allocate if CMA isn't configured
> 
> Changes since the V2 RFC:
> * Based on v6.12
> * Replaced the flags for SVP and Trusted UID memory with a u32 field with
>   unique id for each use case
> * Added dynamic allocation of restricted memory pools
> * Added OP-TEE ABI both with and without FF-A for dynamic restricted memory
> * Added support for FF-A with FFA_LEND
> 
> Changes since the V1 RFC:
> * Based on v6.11
> * Complete rewrite, replacing the restricted heap with TEE_IOC_RSTMEM_ALLOC
> 
> Changes since Olivier's post [2]:
> * Based on Yong Wu's post [1] where much of dma-buf handling is done in
>   the generic restricted heap
> * Simplifications and cleanup
> * New commit message for "dma-buf: heaps: add Linaro restricted dmabuf heap
>   support"
> * Replaced the word "secure" with "restricted" where applicable
> 
> Jens Wiklander (6):
>   tee: add restricted memory allocation
>   optee: account for direction while converting parameters
>   optee: sync secure world ABI headers
>   optee: support restricted memory allocation
>   optee: FF-A: dynamic restricted memory allocation
>   optee: smc abi: dynamic restricted memory allocation
> 
>  drivers/tee/Makefile              |   1 +
>  drivers/tee/optee/Makefile        |   1 +
>  drivers/tee/optee/call.c          |  10 +-
>  drivers/tee/optee/core.c          |   1 +
>  drivers/tee/optee/ffa_abi.c       | 178 +++++++++++++-
>  drivers/tee/optee/optee_ffa.h     |  27 ++-
>  drivers/tee/optee/optee_msg.h     |  65 ++++-
>  drivers/tee/optee/optee_private.h |  75 ++++--
>  drivers/tee/optee/optee_smc.h     |  71 +++++-
>  drivers/tee/optee/rpc.c           |  31 ++-
>  drivers/tee/optee/rstmem.c        | 388 ++++++++++++++++++++++++++++++
>  drivers/tee/optee/smc_abi.c       | 213 ++++++++++++++--
>  drivers/tee/tee_core.c            |  38 ++-
>  drivers/tee/tee_private.h         |   2 +
>  drivers/tee/tee_rstmem.c          | 201 ++++++++++++++++
>  drivers/tee/tee_shm.c             |   2 +
>  drivers/tee/tee_shm_pool.c        |  69 +++++-
>  include/linux/tee_core.h          |  15 ++
>  include/linux/tee_drv.h           |   2 +
>  include/uapi/linux/tee.h          |  44 +++-
>  20 files changed, 1358 insertions(+), 76 deletions(-)
>  create mode 100644 drivers/tee/optee/rstmem.c
>  create mode 100644 drivers/tee/tee_rstmem.c
> 
> 
> base-commit: fac04efc5c793dccbd07e2d59af9f90b7fc0dca4
> -- 
> 2.43.0
>