[RFC,0/1] uio: Add dmabuf import ioctl

Message

Hyun Kwon Feb. 23, 2019, 8:28 p.m. UTC

Hi,

I'm looking to enable platform independent device driver stacks on
Linux. Currently, I have some driver built on top of Linux UIO [1],
and possibly there can be more of such drivers: ex, soft IP drivers
programmed on FPGA. Some device includes data movers such as DMA, and
that requires some mechanism to import external buffers and program
the data movers from user space.

Thus this patch set adds a couple of ioctls to import the dmabuf
and return required information back to user. This allows the user
drivers to use dmabuf compatible external buffers: ex, it's tested
with ION allocator.

I'd like to understand if this is right approach which can be used
to develop the user space software stacks further, especially because
- adding new ioctls to generic uio
- security concerns from exposing low level information: dma addr
For example, vfio isn't option as iommu may not be available for
all such devices on all platforms. So any feedback to move forward
would be appreciated.

Thanks,
-hyun

[1] https://patchwork.kernel.org/patch/10774761/

Hyun Kwon (1):
  uio: Add dma-buf import ioctls

 drivers/uio/Makefile         |   2 +-
 drivers/uio/uio.c            |  43 +++++++++
 drivers/uio/uio_dmabuf.c     | 210 +++++++++++++++++++++++++++++++++++++++++++
 drivers/uio/uio_dmabuf.h     |  26 ++++++
 include/uapi/linux/uio/uio.h |  33 +++++++
 5 files changed, 313 insertions(+), 1 deletion(-)
 create mode 100644 drivers/uio/uio_dmabuf.c
 create mode 100644 drivers/uio/uio_dmabuf.h
 create mode 100644 include/uapi/linux/uio/uio.h