[v5] tee: Use iov_iter to better support shared buffer registration

  Currently it's not possible to register kernel buffers with TEE
which are allocated via vmalloc.

Use iov_iter and associated helper functions to manage the page
registration for all type of memories.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
Update from V4 to V5:
- replace import_ubuf() by iov_iter_ubuf(),
- fix comment in register_shm_helper() function.

Update from V3 to V4:
- improve commit message,
- use import_ubuf() instead of iov_iter_init(),
- move shm_get_kernel_pages in register_shm_helper,
- put back untagged_addr in register_shm_helper(),
- move the comment related to pin pages from shm_get_kernel_pages()
  to register_shm_helper().

Update from V2 to V3:
- break lines longer than 80 columns.

Update from V1 to V2:
- replace ITER_SOURCE by ITER_DEST flag in tee_shm_register_user_buf(),
- replace IS_ERR_OR NULL(shm) by IS_ERR(shm) in tee_shm_register_user_buf().

V1:
The support of buffer registration allocated with vmalloc is no more
available since c83900393aa1 ("tee: Remove vmalloc page support").

This patch is an alternative to a revert and resulted from a discussion
with Christopher Hellwig [1].

This patch has been tested using xtest tool in optee qemu environment [2]
and using the series related to the remoteproc tee that should be
proposed soon [3].

References:
[1] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#m8ec683c44fcd9b69c2aee42eaed0793afac9dd18in
[2] https://optee.readthedocs.io/en/latest/building/devices/qemu.html#build-instructions
[3] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#maca0a1fc897aadd54c7deac432e11473fe970d1d
---
 drivers/tee/tee_shm.c | 78 +++++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 36 deletions(-)
  

On Tue, 5 Dec 2023 at 21:53, Arnaud Pouliquen
<arnaud.pouliquen@foss.st.com> wrote:
>
> Currently it's not possible to register kernel buffers with TEE
> which are allocated via vmalloc.
>
> Use iov_iter and associated helper functions to manage the page
> registration for all type of memories.
>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> Update from V4 to V5:
> - replace import_ubuf() by iov_iter_ubuf(),
> - fix comment in register_shm_helper() function.
>

Looks good to me, feel free to add:

Reviewed-by: Sumit Garg <sumit.garg@linaro.org>

> Update from V3 to V4:
> - improve commit message,
> - use import_ubuf() instead of iov_iter_init(),
> - move shm_get_kernel_pages in register_shm_helper,
> - put back untagged_addr in register_shm_helper(),
> - move the comment related to pin pages from shm_get_kernel_pages()
>   to register_shm_helper().
>
> Update from V2 to V3:
> - break lines longer than 80 columns.
>
> Update from V1 to V2:
> - replace ITER_SOURCE by ITER_DEST flag in tee_shm_register_user_buf(),
> - replace IS_ERR_OR NULL(shm) by IS_ERR(shm) in tee_shm_register_user_buf().
>
> V1:
> The support of buffer registration allocated with vmalloc is no more
> available since c83900393aa1 ("tee: Remove vmalloc page support").
>
> This patch is an alternative to a revert and resulted from a discussion
> with Christopher Hellwig [1].
>
> This patch has been tested using xtest tool in optee qemu environment [2]
> and using the series related to the remoteproc tee that should be
> proposed soon [3].
>
> References:
> [1] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#m8ec683c44fcd9b69c2aee42eaed0793afac9dd18in
> [2] https://optee.readthedocs.io/en/latest/building/devices/qemu.html#build-instructions
> [3] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#maca0a1fc897aadd54c7deac432e11473fe970d1d
> ---
>  drivers/tee/tee_shm.c | 78 +++++++++++++++++++++++--------------------
>  1 file changed, 42 insertions(+), 36 deletions(-)
>
> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index 673cf0359494..731d9028b67f 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -22,23 +22,12 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
>                 put_page(pages[n]);
>  }
>
> -static int shm_get_kernel_pages(unsigned long start, size_t page_count,
> -                               struct page **pages)
> +static void shm_get_kernel_pages(struct page **pages, size_t page_count)
>  {
> -       struct page *page;
>         size_t n;
>
> -       if (WARN_ON_ONCE(is_vmalloc_addr((void *)start) ||
> -                        is_kmap_addr((void *)start)))
> -               return -EINVAL;
> -
> -       page = virt_to_page((void *)start);
> -       for (n = 0; n < page_count; n++) {
> -               pages[n] = page + n;
> +       for (n = 0; n < page_count; n++)
>                 get_page(pages[n]);
> -       }
> -
> -       return page_count;
>  }
>
>  static void release_registered_pages(struct tee_shm *shm)
> @@ -214,13 +203,14 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
>  EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
>
>  static struct tee_shm *
> -register_shm_helper(struct tee_context *ctx, unsigned long addr,
> -                   size_t length, u32 flags, int id)
> +register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
> +                   int id)
>  {
>         struct tee_device *teedev = ctx->teedev;
>         struct tee_shm *shm;
> -       unsigned long start;
> -       size_t num_pages;
> +       unsigned long start, addr;
> +       size_t num_pages, off;
> +       ssize_t len;
>         void *ret;
>         int rc;
>
> @@ -245,31 +235,38 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr,
>         shm->flags = flags;
>         shm->ctx = ctx;
>         shm->id = id;
> -       addr = untagged_addr(addr);
> +       addr = untagged_addr((unsigned long)iter_iov_addr(iter));
>         start = rounddown(addr, PAGE_SIZE);
> -       shm->offset = addr - start;
> -       shm->size = length;
> -       num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
> +       num_pages = iov_iter_npages(iter, INT_MAX);
> +       if (!num_pages) {
> +               ret = ERR_PTR(-ENOMEM);
> +               goto err_ctx_put;
> +       }
> +
>         shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
>         if (!shm->pages) {
>                 ret = ERR_PTR(-ENOMEM);
>                 goto err_free_shm;
>         }
>
> -       if (flags & TEE_SHM_USER_MAPPED)
> -               rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,
> -                                        shm->pages);
> -       else
> -               rc = shm_get_kernel_pages(start, num_pages, shm->pages);
> -       if (rc > 0)
> -               shm->num_pages = rc;
> -       if (rc != num_pages) {
> -               if (rc >= 0)
> -                       rc = -ENOMEM;
> -               ret = ERR_PTR(rc);
> -               goto err_put_shm_pages;
> +       len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,
> +                                    &off);
> +       if (unlikely(len <= 0)) {
> +               ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM);
> +               goto err_free_shm_pages;
>         }
>
> +       /*
> +        * iov_iter_extract_kvec_pages does not get reference on the pages,
> +        * get a reference on them.
> +        */
> +       if (iov_iter_is_kvec(iter))
> +               shm_get_kernel_pages(shm->pages, num_pages);
> +
> +       shm->offset = off;
> +       shm->size = len;
> +       shm->num_pages = num_pages;
> +
>         rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
>                                              shm->num_pages, start);
>         if (rc) {
> @@ -279,10 +276,11 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr,
>
>         return shm;
>  err_put_shm_pages:
> -       if (flags & TEE_SHM_USER_MAPPED)
> +       if (!iov_iter_is_kvec(iter))
>                 unpin_user_pages(shm->pages, shm->num_pages);
>         else
>                 shm_put_kernel_pages(shm->pages, shm->num_pages);
> +err_free_shm_pages:
>         kfree(shm->pages);
>  err_free_shm:
>         kfree(shm);
> @@ -307,6 +305,7 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
>         u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC;
>         struct tee_device *teedev = ctx->teedev;
>         struct tee_shm *shm;
> +       struct iov_iter iter;
>         void *ret;
>         int id;
>
> @@ -319,7 +318,8 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
>         if (id < 0)
>                 return ERR_PTR(id);
>
> -       shm = register_shm_helper(ctx, addr, length, flags, id);
> +       iov_iter_ubuf(&iter, ITER_DEST,  (void __user *)addr, length);
> +       shm = register_shm_helper(ctx, &iter, flags, id);
>         if (IS_ERR(shm)) {
>                 mutex_lock(&teedev->mutex);
>                 idr_remove(&teedev->idr, id);
> @@ -352,8 +352,14 @@ struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
>                                             void *addr, size_t length)
>  {
>         u32 flags = TEE_SHM_DYNAMIC;
> +       struct kvec kvec;
> +       struct iov_iter iter;
> +
> +       kvec.iov_base = addr;
> +       kvec.iov_len = length;
> +       iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, length);
>
> -       return register_shm_helper(ctx, (unsigned long)addr, length, flags, -1);
> +       return register_shm_helper(ctx, &iter, flags, -1);
>  }
>  EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
>
> --
> 2.25.1
>
  

On Tue, Dec 12, 2023 at 6:25 AM Sumit Garg <sumit.garg@linaro.org> wrote:
>
> On Tue, 5 Dec 2023 at 21:53, Arnaud Pouliquen
> <arnaud.pouliquen@foss.st.com> wrote:
> >
> > Currently it's not possible to register kernel buffers with TEE
> > which are allocated via vmalloc.
> >
> > Use iov_iter and associated helper functions to manage the page
> > registration for all type of memories.
> >
> > Suggested-by: Christoph Hellwig <hch@infradead.org>
> > Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> > ---
> > Update from V4 to V5:
> > - replace import_ubuf() by iov_iter_ubuf(),
> > - fix comment in register_shm_helper() function.
> >
>
> Looks good to me, feel free to add:
>
> Reviewed-by: Sumit Garg <sumit.garg@linaro.org>

I'm picking up this.

Thanks,
Jens

>
> > Update from V3 to V4:
> > - improve commit message,
> > - use import_ubuf() instead of iov_iter_init(),
> > - move shm_get_kernel_pages in register_shm_helper,
> > - put back untagged_addr in register_shm_helper(),
> > - move the comment related to pin pages from shm_get_kernel_pages()
> >   to register_shm_helper().
> >
> > Update from V2 to V3:
> > - break lines longer than 80 columns.
> >
> > Update from V1 to V2:
> > - replace ITER_SOURCE by ITER_DEST flag in tee_shm_register_user_buf(),
> > - replace IS_ERR_OR NULL(shm) by IS_ERR(shm) in tee_shm_register_user_buf().
> >
> > V1:
> > The support of buffer registration allocated with vmalloc is no more
> > available since c83900393aa1 ("tee: Remove vmalloc page support").
> >
> > This patch is an alternative to a revert and resulted from a discussion
> > with Christopher Hellwig [1].
> >
> > This patch has been tested using xtest tool in optee qemu environment [2]
> > and using the series related to the remoteproc tee that should be
> > proposed soon [3].
> >
> > References:
> > [1] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#m8ec683c44fcd9b69c2aee42eaed0793afac9dd18in
> > [2] https://optee.readthedocs.io/en/latest/building/devices/qemu.html#build-instructions
> > [3] https://lore.kernel.org/linux-arm-kernel/18a8528d-7d9d-6ed0-0045-5ee47dd39fb2@foss.st.com/T/#maca0a1fc897aadd54c7deac432e11473fe970d1d
> > ---
> >  drivers/tee/tee_shm.c | 78 +++++++++++++++++++++++--------------------
> >  1 file changed, 42 insertions(+), 36 deletions(-)
> >
> > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> > index 673cf0359494..731d9028b67f 100644
> > --- a/drivers/tee/tee_shm.c
> > +++ b/drivers/tee/tee_shm.c
> > @@ -22,23 +22,12 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
> >                 put_page(pages[n]);
> >  }
> >
> > -static int shm_get_kernel_pages(unsigned long start, size_t page_count,
> > -                               struct page **pages)
> > +static void shm_get_kernel_pages(struct page **pages, size_t page_count)
> >  {
> > -       struct page *page;
> >         size_t n;
> >
> > -       if (WARN_ON_ONCE(is_vmalloc_addr((void *)start) ||
> > -                        is_kmap_addr((void *)start)))
> > -               return -EINVAL;
> > -
> > -       page = virt_to_page((void *)start);
> > -       for (n = 0; n < page_count; n++) {
> > -               pages[n] = page + n;
> > +       for (n = 0; n < page_count; n++)
> >                 get_page(pages[n]);
> > -       }
> > -
> > -       return page_count;
> >  }
> >
> >  static void release_registered_pages(struct tee_shm *shm)
> > @@ -214,13 +203,14 @@ struct tee_shm *tee_shm_alloc_priv_buf(struct tee_context *ctx, size_t size)
> >  EXPORT_SYMBOL_GPL(tee_shm_alloc_priv_buf);
> >
> >  static struct tee_shm *
> > -register_shm_helper(struct tee_context *ctx, unsigned long addr,
> > -                   size_t length, u32 flags, int id)
> > +register_shm_helper(struct tee_context *ctx, struct iov_iter *iter, u32 flags,
> > +                   int id)
> >  {
> >         struct tee_device *teedev = ctx->teedev;
> >         struct tee_shm *shm;
> > -       unsigned long start;
> > -       size_t num_pages;
> > +       unsigned long start, addr;
> > +       size_t num_pages, off;
> > +       ssize_t len;
> >         void *ret;
> >         int rc;
> >
> > @@ -245,31 +235,38 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr,
> >         shm->flags = flags;
> >         shm->ctx = ctx;
> >         shm->id = id;
> > -       addr = untagged_addr(addr);
> > +       addr = untagged_addr((unsigned long)iter_iov_addr(iter));
> >         start = rounddown(addr, PAGE_SIZE);
> > -       shm->offset = addr - start;
> > -       shm->size = length;
> > -       num_pages = (roundup(addr + length, PAGE_SIZE) - start) / PAGE_SIZE;
> > +       num_pages = iov_iter_npages(iter, INT_MAX);
> > +       if (!num_pages) {
> > +               ret = ERR_PTR(-ENOMEM);
> > +               goto err_ctx_put;
> > +       }
> > +
> >         shm->pages = kcalloc(num_pages, sizeof(*shm->pages), GFP_KERNEL);
> >         if (!shm->pages) {
> >                 ret = ERR_PTR(-ENOMEM);
> >                 goto err_free_shm;
> >         }
> >
> > -       if (flags & TEE_SHM_USER_MAPPED)
> > -               rc = pin_user_pages_fast(start, num_pages, FOLL_WRITE,
> > -                                        shm->pages);
> > -       else
> > -               rc = shm_get_kernel_pages(start, num_pages, shm->pages);
> > -       if (rc > 0)
> > -               shm->num_pages = rc;
> > -       if (rc != num_pages) {
> > -               if (rc >= 0)
> > -                       rc = -ENOMEM;
> > -               ret = ERR_PTR(rc);
> > -               goto err_put_shm_pages;
> > +       len = iov_iter_extract_pages(iter, &shm->pages, LONG_MAX, num_pages, 0,
> > +                                    &off);
> > +       if (unlikely(len <= 0)) {
> > +               ret = len ? ERR_PTR(len) : ERR_PTR(-ENOMEM);
> > +               goto err_free_shm_pages;
> >         }
> >
> > +       /*
> > +        * iov_iter_extract_kvec_pages does not get reference on the pages,
> > +        * get a reference on them.
> > +        */
> > +       if (iov_iter_is_kvec(iter))
> > +               shm_get_kernel_pages(shm->pages, num_pages);
> > +
> > +       shm->offset = off;
> > +       shm->size = len;
> > +       shm->num_pages = num_pages;
> > +
> >         rc = teedev->desc->ops->shm_register(ctx, shm, shm->pages,
> >                                              shm->num_pages, start);
> >         if (rc) {
> > @@ -279,10 +276,11 @@ register_shm_helper(struct tee_context *ctx, unsigned long addr,
> >
> >         return shm;
> >  err_put_shm_pages:
> > -       if (flags & TEE_SHM_USER_MAPPED)
> > +       if (!iov_iter_is_kvec(iter))
> >                 unpin_user_pages(shm->pages, shm->num_pages);
> >         else
> >                 shm_put_kernel_pages(shm->pages, shm->num_pages);
> > +err_free_shm_pages:
> >         kfree(shm->pages);
> >  err_free_shm:
> >         kfree(shm);
> > @@ -307,6 +305,7 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
> >         u32 flags = TEE_SHM_USER_MAPPED | TEE_SHM_DYNAMIC;
> >         struct tee_device *teedev = ctx->teedev;
> >         struct tee_shm *shm;
> > +       struct iov_iter iter;
> >         void *ret;
> >         int id;
> >
> > @@ -319,7 +318,8 @@ struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx,
> >         if (id < 0)
> >                 return ERR_PTR(id);
> >
> > -       shm = register_shm_helper(ctx, addr, length, flags, id);
> > +       iov_iter_ubuf(&iter, ITER_DEST,  (void __user *)addr, length);
> > +       shm = register_shm_helper(ctx, &iter, flags, id);
> >         if (IS_ERR(shm)) {
> >                 mutex_lock(&teedev->mutex);
> >                 idr_remove(&teedev->idr, id);
> > @@ -352,8 +352,14 @@ struct tee_shm *tee_shm_register_kernel_buf(struct tee_context *ctx,
> >                                             void *addr, size_t length)
> >  {
> >         u32 flags = TEE_SHM_DYNAMIC;
> > +       struct kvec kvec;
> > +       struct iov_iter iter;
> > +
> > +       kvec.iov_base = addr;
> > +       kvec.iov_len = length;
> > +       iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, length);
> >
> > -       return register_shm_helper(ctx, (unsigned long)addr, length, flags, -1);
> > +       return register_shm_helper(ctx, &iter, flags, -1);
> >  }
> >  EXPORT_SYMBOL_GPL(tee_shm_register_kernel_buf);
> >
> > --
> > 2.25.1
> >