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@xxxxxxxxx > * 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 > -- Simona Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
