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

From: Jason Wang <jasowang@redhat.com>
To: Tiwei Bie <tiwei.bie@intel.com>,
	mst@redhat.com, alex.williamson@redhat.com,
	maxime.coquelin@redhat.com
Cc: kvm@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	zhihong.wang@intel.com, lingshan.zhu@intel.com
Subject: Re: [RFC v4 0/3] vhost: introduce mdev based hardware backend
Date: Tue, 17 Sep 2019 09:29:42 +0800	[thread overview]
Message-ID: <980958b0-b541-6e37-830e-f2b82358845b__44279.6777629823$1568683806$gmane$org@redhat.com> (raw)
In-Reply-To: <20190917010204.30376-1-tiwei.bie@intel.com>

On 2019/9/17 上午9:02, Tiwei Bie wrote:
> 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

Thanks a lot for the patches.

Per Michael request, the API in [1] might need some tweak, I want to 
introduce some device specific parent_ops instead of vfio specific one. 
This RFC has been posted at https://lkml.org/lkml/2019/9/12/151.

>
> 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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