linux-kernel - Re: [PATCH v2 0/9] memfd: add sealing to hugetlb-backed memory

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Date:   Mon, 6 Nov 2017 17:47:21 -0800
From:   Mike Kravetz <mike.kravetz@...cle.com>
To:     Marc-André Lureau <marcandre.lureau@...hat.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     aarcange@...hat.com, hughd@...gle.com, nyc@...omorphy.com,
        David Herrmann <dh.herrmann@...il.com>
Subject: Re: [PATCH v2 0/9] memfd: add sealing to hugetlb-backed memory

On 11/06/2017 06:39 AM, Marc-André Lureau wrote:
> Hi,
> 
> Recently, Mike Kravetz added hugetlbfs support to memfd. However, he
> didn't add sealing support. One of the reasons to use memfd is to have
> shared memory sealing when doing IPC or sharing memory with another
> process with some extra safety. qemu uses shared memory & hugetables
> with vhost-user (used by dpdk), so it is reasonable to use memfd
> now instead for convenience and security reasons.

Thanks for doing this.

I will create a patch to restructure the code such that memfd_create (and
file sealing) is split out and will depend on CONFIG_TMPFS -or-
CONFIG_HUGETLBFS.  I think this can wait to go in until after this patch
series.  Unless, someone prefers that it go in first?

-- 
Mike Kravetz


> 
> Thanks!
> 
> v1->v2: after Mike review,
> - add "memfd-hugetlb:" prefix in memfd-test
> - run fuse test on hugetlb backend memory
> - rename function memfd_file_get_seals() -> memfd_file_seals_ptr()
> - update commit messages
> - added reviewed-by tags
> 
> RFC->v1:
> - split rfc patch, after early review feedback
> - added patch for memfd-test changes
> - fix build with hugetlbfs disabled
> - small code and commit messages improvements
> 
> Marc-André Lureau (9):
>   shmem: unexport shmem_add_seals()/shmem_get_seals()
>   shmem: rename functions that are memfd-related
>   hugetlb: expose hugetlbfs_inode_info in header
>   hugetlbfs: implement memfd sealing
>   shmem: add sealing support to hugetlb-backed memfd
>   memfd-tests: test hugetlbfs sealing
>   memfd-test: add 'memfd-hugetlb:' prefix when testing hugetlbfs
>   memfd-test: move common code to a shared unit
>   memfd-test: run fuse test on hugetlb backend memory
> 
>  fs/fcntl.c                                     |   2 +-
>  fs/hugetlbfs/inode.c                           |  39 +++--
>  include/linux/hugetlb.h                        |  11 ++
>  include/linux/shmem_fs.h                       |   6 +-
>  mm/shmem.c                                     |  59 ++++---
>  tools/testing/selftests/memfd/Makefile         |   5 +
>  tools/testing/selftests/memfd/common.c         |  45 ++++++
>  tools/testing/selftests/memfd/common.h         |   9 ++
>  tools/testing/selftests/memfd/fuse_test.c      |  36 +++--
>  tools/testing/selftests/memfd/memfd_test.c     | 212 ++++---------------------
>  tools/testing/selftests/memfd/run_fuse_test.sh |   2 +-
>  tools/testing/selftests/memfd/run_tests.sh     |   1 +
>  12 files changed, 195 insertions(+), 232 deletions(-)
>  create mode 100644 tools/testing/selftests/memfd/common.c
>  create mode 100644 tools/testing/selftests/memfd/common.h
>