On Fri, Nov 27, 2020 at 05:41:14PM +0100, Daniel Vetter wrote:

Hi all

Another update of my patch series to clamp down a bunch of races and gaps
around follow_pfn and other access to iomem mmaps. Previous version:

v1: https://lore.kernel.org/dri-devel/20201007164426.1812530-1-daniel.vetter@ffwll.ch/ (local)
v2: https://lore.kernel.org/dri-devel/20201009075934.3509076-1-daniel.vetter@ffwll.ch (local)
v3: https://lore.kernel.org/dri-devel/20201021085655.1192025-1-daniel.vetter@ffwll.ch/ (local)
v4: https://lore.kernel.org/dri-devel/20201026105818.2585306-1-daniel.vetter@ffwll.ch/ (local)
v5: https://lore.kernel.org/dri-devel/20201030100815.2269-1-daniel.vetter@ffwll.ch/ (local)
v6: https://lore.kernel.org/dri-devel/20201119144146.1045202-1-daniel.vetter@ffwll.ch/ (local)

And the discussion that sparked this journey:

https://lore.kernel.org/dri-devel/20201007164426.1812530-1-daniel.vetter@ffwll.ch/ (local)

I think the first 12 patches are ready for landing. The parts starting
with "mm: Add unsafe_follow_pfn" probably need more baking time.

Andrew, can you please pick these up, or do you prefer I do a topic branch
and send them to Linus directly in the next merge window?

Changes in v7:
- more acks/reviews
- reordered with the ready pieces at the front
- simplified the new follow_pfn function as Jason suggested

Changes in v6:
- Tested v4l userptr as Tomasz suggested. No boom observed
- Added RFC for locking down follow_pfn, per discussion with Christoph and
  Jason.
- Explain why pup_fast is safe in relevant patches, there was a bit a
  confusion when discussing v5.
- Fix up the resource patch, with CONFIG_IO_STRICT_DEVMEM it crashed on
  boot due to an unintended change (reported by John)

Changes in v5:
- Tomasz found some issues in the media patches
- Polish suggested by Christoph for the unsafe_follow_pfn patch

Changes in v4:
- Drop the s390 patch, that was very stand-alone and now queued up to land
  through s390 trees.
- Comment polish per Dan's review.

Changes in v3:
- Bunch of polish all over, no functional changes aside from one barrier
  in the resource code, for consistency.
- A few more r-b tags.

Changes in v2:
- tons of small polish&fixes all over, thanks to all the reviewers who
  spotted issues
- I managed to test at least the generic_access_phys and pci mmap revoke
  stuff with a few gdb sessions using our i915 debug tools (hence now also
  the drm/i915 patch to properly request all the pci bar regions)
- reworked approach for the pci mmap revoke: Infrastructure moved into
  kernel/resource.c, address_space mapping is now set up at open time for
  everyone (which required some sysfs changes). Does indeed look a lot
  cleaner and a lot less invasive than I feared at first.

Coments and review on the remaining bits very much welcome, especially
from the kvm and vfio side.

Cheers, Daniel

Daniel Vetter (17):
  drm/exynos: Stop using frame_vector helpers
  drm/exynos: Use FOLL_LONGTERM for g2d cmdlists
  misc/habana: Stop using frame_vector helpers
  misc/habana: Use FOLL_LONGTERM for userptr
  mm/frame-vector: Use FOLL_LONGTERM
  media: videobuf2: Move frame_vector into media subsystem
  mm: Close race in generic_access_phys
  PCI: Obey iomem restrictions for procfs mmap
  /dev/mem: Only set filp->f_mapping
  resource: Move devmem revoke code to resource framework
  sysfs: Support zapping of binary attr mmaps
  PCI: Revoke mappings like devmem

As Jason suggested, I've pulled the first 1 patches into a topic branch.

Stephen, can you please add the below to linux-next for the 5.12 merge
window?

git://anongit.freedesktop.org/drm/drm topic/iomem-mmap-vs-gup

Once this part has landed I'll see what to do with the below part.

Thanks, Daniel

  mm: Add unsafe_follow_pfn
  media/videobuf1|2: Mark follow_pfn usage as unsafe
  vfio/type1: Mark follow_pfn as unsafe
  kvm: pass kvm argument to follow_pfn callsites
  mm: add mmu_notifier argument to follow_pfn

 arch/powerpc/kvm/book3s_64_mmu_hv.c           |   2 +-
 arch/powerpc/kvm/book3s_64_mmu_radix.c        |   2 +-
 arch/powerpc/kvm/e500_mmu_host.c              |   2 +-
 arch/x86/kvm/mmu/mmu.c                        |   8 +-
 drivers/char/mem.c                            |  86 +-------------
 drivers/gpu/drm/exynos/Kconfig                |   1 -
 drivers/gpu/drm/exynos/exynos_drm_g2d.c       |  48 ++++----
 drivers/media/common/videobuf2/Kconfig        |   1 -
 drivers/media/common/videobuf2/Makefile       |   1 +
 .../media/common/videobuf2}/frame_vector.c    |  57 ++++-----
 .../media/common/videobuf2/videobuf2-memops.c |   3 +-
 drivers/media/platform/omap/Kconfig           |   1 -
 drivers/media/v4l2-core/videobuf-dma-contig.c |   2 +-
 drivers/misc/habanalabs/Kconfig               |   1 -
 drivers/misc/habanalabs/common/habanalabs.h   |   6 +-
 drivers/misc/habanalabs/common/memory.c       |  52 +++-----
 drivers/pci/pci-sysfs.c                       |   4 +
 drivers/pci/proc.c                            |   6 +
 drivers/vfio/vfio_iommu_type1.c               |   4 +-
 fs/sysfs/file.c                               |  11 ++
 include/linux/ioport.h                        |   6 +-
 include/linux/kvm_host.h                      |   9 +-
 include/linux/mm.h                            |  50 +-------
 include/linux/sysfs.h                         |   2 +
 include/media/frame_vector.h                  |  47 ++++++++
 include/media/videobuf2-core.h                |   1 +
 kernel/resource.c                             |  98 ++++++++++++++-
 mm/Kconfig                                    |   3 -
 mm/Makefile                                   |   1 -
 mm/memory.c                                   | 112 +++++++++++++++---
 mm/nommu.c                                    |  16 ++-
 security/Kconfig                              |  13 ++
 virt/kvm/kvm_main.c                           |  56 +++++----
 33 files changed, 413 insertions(+), 299 deletions(-)
 rename {mm => drivers/media/common/videobuf2}/frame_vector.c (84%)
 create mode 100644 include/media/frame_vector.h

-- 
2.29.2

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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch