Re: [PATCH 0/3] add VFIO mdev support for DFL devices

[Tom Rix <trix@redhat.com>]

This is a new interface, the documentation needs to go

into greater detail. I am particularly interested in the user workflow.

This seems like it would work only for kernel modules. 

Please describe both in the documentation.

A sample of a user mode driver would be helpful.

Is putting driver_override using sysfs for each device scalable ? would a list sets of {feature id,files}'s the vfio driver respond to better ? 

To be consistent the mdev driver file name should be dfl-vfio-mdev.c

There should be an opt-in flag for drivers being overridden instead of blanket approval of all drivers.

Tom

On 9/8/20 12:13 AM, Xu Yilun wrote:
> These patches depend on the patchset: "Modularization of DFL private
> feature drivers" & "add dfl bus support to MODULE_DEVICE_TABLE()"
>
> https://lore.kernel.org/linux-fpga/1599488581-16386-1-git-send-email-yilun.xu@intel.com/
>
> This patchset provides an VFIO Mdev driver for dfl devices. It makes
> possible for dfl devices be direct accessed from userspace.
>
> Xu Yilun (3):
>   fpga: dfl: add driver_override support
>   fpga: dfl: VFIO mdev support for DFL devices
>   Documentation: fpga: dfl: Add description for VFIO Mdev support
>
>  Documentation/ABI/testing/sysfs-bus-dfl |  20 ++
>  Documentation/fpga/dfl.rst              |  20 ++
>  drivers/fpga/Kconfig                    |   9 +
>  drivers/fpga/Makefile                   |   1 +
>  drivers/fpga/dfl.c                      |  54 ++++-
>  drivers/fpga/vfio-mdev-dfl.c            | 391 ++++++++++++++++++++++++++++++++
>  include/linux/fpga/dfl-bus.h            |   2 +
>  7 files changed, 496 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/fpga/vfio-mdev-dfl.c
>