On Tue, Oct 15, 2019 at 11:37:17AM +0800, Jason Wang wrote:
On 2019/10/15 上午1:49, Stefan Hajnoczi wrote:
On Fri, Oct 11, 2019 at 04:15:50PM +0800, Jason Wang wrote:
There are hardware that can do virtio datapath offloading while having its own control path. This path tries to implement a mdev based unified API to support using kernel virtio driver to drive those devices. This is done by introducing a new mdev transport for virtio (virtio_mdev) and register itself as a new kind of mdev driver. Then it provides a unified way for kernel virtio driver to talk with mdev device implementation.
Though the series only contains kernel driver support, the goal is to make the transport generic enough to support userspace drivers. This means vhost-mdev[1] could be built on top as well by resuing the transport.
A sample driver is also implemented which simulate a virito-net loopback ethernet device on top of vringh + workqueue. This could be used as a reference implementation for real hardware driver.
Consider mdev framework only support VFIO device and driver right now, this series also extend it to support other types. This is done through introducing class id to the device and pairing it with id_talbe claimed by the driver. On top, this seris also decouple device specific parents ops out of the common ones.
I was curious so I took a quick look and posted comments.
I guess this driver runs inside the guest since it registers virtio devices?
It could run in either guest or host. But the main focus is to run in the host then we can use virtio drivers in containers.
If this is used with physical PCI devices that support datapath offloading then how are physical devices presented to the guest without SR-IOV?
We will do control path meditation through vhost-mdev[1] and vhost-vfio[2]. Then we will present a full virtio compatible ethernet device for guest.
SR-IOV is not a must, any mdev device that implements the API defined in patch 5 can be used by this framework.
What I'm trying to understand is: if you want to present a virtio-pci device to the guest (e.g. using vhost-mdev or vhost-vfio), then how is that related to this patch series?
Does this mean this patch series is useful mostly for presenting virtio devices to containers or the host?
Stefan