[RFC v4 0/3] vhost: introduce mdev based hardware backend

From: Tiwei Bie
Date: Mon Sep 16 2019 - 21:05:00 EST


This RFC is to demonstrate below ideas,

a) Build vhost-mdev on top of the same abstraction defined in
the virtio-mdev series [1];

b) Introduce /dev/vhost-mdev to do vhost ioctls and support
setting mdev device as backend;

Now the userspace API looks like this:

- Userspace generates a compatible mdev device;

- Userspace opens this mdev device with VFIO API (including
doing IOMMU programming for this mdev device with VFIO's
container/group based interface);

- Userspace opens /dev/vhost-mdev and gets vhost fd;

- Userspace uses vhost ioctls to setup vhost (userspace should
do VHOST_MDEV_SET_BACKEND ioctl with VFIO group fd and device
fd first before doing other vhost ioctls);

Only compile test has been done for this series for now.

RFCv3: https://patchwork.kernel.org/patch/11117785/

[1] https://lkml.org/lkml/2019/9/10/135

Tiwei Bie (3):
vfio: support getting vfio device from device fd
vfio: support checking vfio driver by device ops
vhost: introduce mdev based hardware backend

drivers/vfio/mdev/vfio_mdev.c | 3 +-
drivers/vfio/vfio.c | 32 +++
drivers/vhost/Kconfig | 9 +
drivers/vhost/Makefile | 3 +
drivers/vhost/mdev.c | 462 +++++++++++++++++++++++++++++++
drivers/vhost/vhost.c | 39 ++-
drivers/vhost/vhost.h | 6 +
include/linux/vfio.h | 11 +
include/uapi/linux/vhost.h | 10 +
include/uapi/linux/vhost_types.h | 5 +
10 files changed, 573 insertions(+), 7 deletions(-)
create mode 100644 drivers/vhost/mdev.c

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2.17.1