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    SubjectRe: [PATCH v1 07/14] tee: optee: add shared buffer registration functions
    On Thu, Sep 28, 2017 at 09:04:04PM +0300, Volodymyr Babchuk wrote:
    > From: Volodymyr Babchuk <vlad.babchuk@gmail.com>
    >
    > This change adds ops for shm_(un)register functions in tee interface.
    > Client application can use these functions to (un)register an own shared
    > buffer in OP-TEE address space. This allows zero copy data sharing between
    > Normal and Secure Worlds.
    >
    > Please note that while those functions were added to optee code,
    > it does not report to userspace that those functions are available.
    > OP-TEE code does not set TEE_GEN_CAP_REG_MEM flag. This flag will be
    > enabled only after all other features of dynamic shared memory will be
    > implemented in subsequent patches.

    While it's not adveritsed to the user, AFAICT the user could still
    invoke these via ioctls, right?

    Is there a problem if the user were to do so, or is it simply not useful
    without the other features?

    [...]

    > +int optee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
    > + struct page **pages, size_t num_pages)
    > +{

    > + pages_array = optee_allocate_pages_array(num_pages);
    > + if (!pages_array)
    > + return -ENOMEM;

    > + msg_arg->params->u.tmem.buf_ptr = virt_to_phys(pages_array) |
    > + tee_shm_get_page_offset(shm);

    This doesn't look right. Why is the shm page offset being orred-in to
    the pages_array physical address? They're completely separate objects.

    Thanks,
    Mark.

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