Re: [PATCH V8 0/6] mdev based hardware virtio offloading support

From: Jason Wang
Date: Wed Nov 06 2019 - 23:12:10 EST



On 2019/11/7 äå5:13, Alex Williamson wrote:
On Wed, 6 Nov 2019 14:25:23 -0500
"Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:

On Wed, Nov 06, 2019 at 12:03:12PM -0700, Alex Williamson wrote:
On Wed, 6 Nov 2019 11:56:46 +0800
Jason Wang <jasowang@xxxxxxxxxx> wrote:
On 2019/11/6 äå1:58, Alex Williamson wrote:
On Tue, 5 Nov 2019 17:32:34 +0800
Jason Wang <jasowang@xxxxxxxxxx> wrote:
Hi all:

There are hardwares 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.

Also a real ICF VF driver was also posted here[2] which is a good
reference for vendors who is interested in their own virtio datapath
offloading product.

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.

Pktgen test was done with virito-net + mvnet loop back device.

Please review.

[1] https://lkml.org/lkml/2019/10/31/440
[2] https://lkml.org/lkml/2019/10/15/1226

Changes from V7:
- drop {set|get}_mdev_features for virtio
- typo and comment style fixes
Seems we're nearly there, all the remaining comments are relatively
superficial, though I would appreciate a v9 addressing them as well as
the checkpatch warnings:

https://patchwork.freedesktop.org/series/68977/

Will do.

Btw, do you plan to merge vhost-mdev patch on top? Or you prefer it to
go through Michael's vhost tree?
I can include it if you wish. The mdev changes are isolated enough in
that patch that I wouldn't presume it, but clearly it would require
less merge coordination to drop it in my tree. Let me know. Thanks,

Alex
I'm fine with merging through your tree. If you do, feel free to
include

Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
AFAICT, it looks like we're expecting at least one more version of
Tiwei's patch after V5, so it'd probably be best to provide the ack and
go-ahead on that next version so there's no confusion. Thanks,

Alex


Yes, it's probably need a V6. Will give ack there.

Thanks