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SubjectRe: [PATCH v1 00/14] tee: optee: add dynamic shared memory support
Hi,

On Thu, Sep 28, 2017 at 09:03:57PM +0300, Volodymyr Babchuk wrote:
> From: Volodymyr Babchuk <vlad.babchuk@gmail.com>
>
> This patch series enables dynamic shared memory support in the TEE
> subsystem as a whole and in OP-TEE in particular.
>
> Global Platform TEE specification [1] allows client applications
> to register part of own memory as a shared buffer between
> application and TEE. This allows fast zero-copy communication between
> TEE and REE. But current implementation of TEE in Linux does not support
> this feature.
>
> Also, current implementation of OP-TEE transport uses fixed size
> pre-shared buffer for all communications with OP-TEE OS. This is okay
> in the most use cases. But this prevents use of OP-TEE in virtualized
> environments, because:
> a) We can't share the same buffer between different virtual machines
> b) Physically contiguous memory as seen by VM can be non-contiguous
> in reality (and as seen by OP-TEE OS) due to second stage of
> MMU translation.
> c) Size of this pre-shared buffer is limited.

I'm afraid that I don't follow the arguments for virtualized OP-TEE
usage.

In a virtualised environment, TEE access *must* be mediated via the
hypervisor, which can virtualise the interface, pin pages, etc.

Could you elaborate on how you expect TEE access to work in a
virtualised environment?

Thanks,
Mark.

> So, first part of this patch series adds generic register/unregister
> interface to tee subsystem. Next patches add necessary features
> into OP-TEE driver, so it can use not only static pre-shared buffer,
> but whole RAM to communicate with OP-TEE OS.
>
> [1] https://www.globalplatform.org/specificationsdevice.asp
>
> Jens Wiklander (2):
> tee: flexible shared memory pool creation
> tee: add register user memory
>
> Volodymyr Babchuk (12):
> tee: shm: add accessors for buffer size and page offset
> tee: shm: add page accessor functions
> tee: optee: Update protocol definitions
> tee: optee: add page list manipulation functions
> tee: optee: add shared buffer registration functions
> tee: optee: add registered shared parameters handling
> tee: optee: add registered buffers handling into RPC calls
> tee: optee: store OP-TEE capabilities in private data
> tee: optee: add optee-specific shared pool implementation
> tee: optee: enable dynamic SHM support
> tee: use reference counting for tee_context
> tee: shm: inline tee_shm getter functions
>
> drivers/tee/optee/Makefile | 1 +
> drivers/tee/optee/call.c | 131 +++++++++++++++++++++-
> drivers/tee/optee/core.c | 160 +++++++++++++++++++++------
> drivers/tee/optee/optee_msg.h | 38 ++++++-
> drivers/tee/optee/optee_private.h | 26 ++++-
> drivers/tee/optee/optee_smc.h | 7 ++
> drivers/tee/optee/rpc.c | 72 ++++++++++--
> drivers/tee/optee/shm_pool.c | 75 +++++++++++++
> drivers/tee/optee/shm_pool.h | 23 ++++
> drivers/tee/tee_core.c | 81 ++++++++++++--
> drivers/tee/tee_private.h | 60 +---------
> drivers/tee/tee_shm.c | 226 +++++++++++++++++++++++++++++++-------
> drivers/tee/tee_shm_pool.c | 165 +++++++++++++++++-----------
> include/linux/tee_drv.h | 184 ++++++++++++++++++++++++++++++-
> include/uapi/linux/tee.h | 30 +++++
> 15 files changed, 1058 insertions(+), 221 deletions(-)
> create mode 100644 drivers/tee/optee/shm_pool.c
> create mode 100644 drivers/tee/optee/shm_pool.h
>
> --
> 2.7.4
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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