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References: <20230203-get_kernel_pages-v2-0-f1dc4af273f1@intel.com> <20230203-get_kernel_pages-v2-2-f1dc4af273f1@intel.com>
In-Reply-To: <20230203-get_kernel_pages-v2-2-f1dc4af273f1@intel.com>
From:   Sumit Garg <sumit.garg@linaro.org>
Date:   Mon, 6 Feb 2023 11:46:45 +0530
Message-ID: <CAFA6WYMoVHWvzSBeR9xTayqqCXqRqsvMZS7WW0rCXX_VsOVWoA@mail.gmail.com>
Subject: Re: [PATCH v2 2/4] tee: Remove vmalloc page support
To:     Ira Weiny <ira.weiny@intel.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christoph Hellwig <hch@lst.de>, linux-kernel@vger.kernel.org,
        op-tee@lists.trustedfirmware.org, linux-mm@kvack.org,
        Jens Wiklander <jens.wiklander@linaro.org>,
        "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
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Precedence: bulk

On Sat, 4 Feb 2023 at 09:36, Ira Weiny <ira.weiny@intel.com> wrote:
>
> The kernel pages used by shm_get_kernel_pages() are allocated using
> GFP_KERNEL through the following call stack:
>
> trusted_instantiate()
>         trusted_payload_alloc() -> GFP_KERNEL
>         <trusted key op>
>                 tee_shm_register_kernel_buf()
>                         register_shm_helper()
>                                 shm_get_kernel_pages()
>
> Where <trusted key op> is one of:
>
>         trusted_key_unseal()
>         trusted_key_get_random()
>         trusted_key_seal()
>
> Remove the vmalloc page support from shm_get_kernel_pages().  Replace
> with a warn on once.
>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> ---
>  drivers/tee/tee_shm.c | 36 ++++++++++++------------------------
>  1 file changed, 12 insertions(+), 24 deletions(-)
>

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

-Sumit

> diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
> index 27295bda3e0b..527a6eabc03e 100644
> --- a/drivers/tee/tee_shm.c
> +++ b/drivers/tee/tee_shm.c
> @@ -24,37 +24,25 @@ static void shm_put_kernel_pages(struct page **pages, size_t page_count)
>  static int shm_get_kernel_pages(unsigned long start, size_t page_count,
>                                 struct page **pages)
>  {
> +       struct kvec *kiov;
>         size_t n;
>         int rc;
>
> -       if (is_vmalloc_addr((void *)start)) {
> -               struct page *page;
> -
> -               for (n = 0; n < page_count; n++) {
> -                       page = vmalloc_to_page((void *)(start + PAGE_SIZE * n));
> -                       if (!page)
> -                               return -ENOMEM;
> -
> -                       get_page(page);
> -                       pages[n] = page;
> -               }
> -               rc = page_count;
> -       } else {
> -               struct kvec *kiov;
> -
> -               kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
> -               if (!kiov)
> -                       return -ENOMEM;
> +       if (WARN_ON_ONCE(is_vmalloc_addr((void *)start)))
> +               return -EINVAL;
>
> -               for (n = 0; n < page_count; n++) {
> -                       kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
> -                       kiov[n].iov_len = PAGE_SIZE;
> -               }
> +       kiov = kcalloc(page_count, sizeof(*kiov), GFP_KERNEL);
> +       if (!kiov)
> +               return -ENOMEM;
>
> -               rc = get_kernel_pages(kiov, page_count, 0, pages);
> -               kfree(kiov);
> +       for (n = 0; n < page_count; n++) {
> +               kiov[n].iov_base = (void *)(start + n * PAGE_SIZE);
> +               kiov[n].iov_len = PAGE_SIZE;
>         }
>
> +       rc = get_kernel_pages(kiov, page_count, 0, pages);
> +       kfree(kiov);
> +
>         return rc;
>  }
>
>
> --
> 2.39.1