From: Jason Wang <jasowang@redhat.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
intel-gfx@lists.freedesktop.org,
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alex.williamson@redhat.com, mst@redhat.com, tiwei.bie@intel.com,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, cohuck@redhat.com,
maxime.coquelin@redhat.com, cunming.liang@intel.com,
zhihong.wang@intel.com, rob.miller@broadcom.com,
xiao.w.wang@intel.com, haotian.wang@sifive.com,
zhenyuw@linux.intel.com, zhi.a.wang@intel.com,
jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com,
rodrigo.vivi@intel.com, airlied@linux.ie, daniel@ffwll.ch,
farman@linux.ibm.com, pasic@linux.ibm.com, sebott@linux.ibm.com,
oberpar@linux.ibm.com, heiko.carstens@de.ibm.com,
gor@linux.ibm.com, borntraeger@de.ibm.com,
akrowiak@linux.ibm.com, freude@linux.ibm.com,
lingshan.zhu@intel.com, idos@mellanox.com, eperezma@redhat.com,
lulu@redhat.com, parav@mellanox.com,
christophe.de.dinechin@gmail.com, kevin.tian@intel.com
Subject: Re: [PATCH V3 0/7] mdev based hardware virtio offloading support
Date: Thu, 17 Oct 2019 09:42:53 +0800 [thread overview]
Message-ID: <ba81e603-cb7d-b152-8fae-97f070a7e460@redhat.com> (raw)
In-Reply-To: <20191015143720.GA13108@stefanha-x1.localdomain>
On 2019/10/15 下午10:37, Stefan Hajnoczi wrote:
> 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?
This series introduce some infrastructure that would be used by vhost-mdev:
1) allow new type of mdev devices/drivers other than vfio (through
class_id and device ops)
2) a set of virtio specific callbacks that will be used by both
vhost-mdev and virtio-mdev defined in patch 5
Then vhost-mdev can be implemented on top: a new mdev class id but reuse
the callback defined in 2. Through this way the parent can provides a
single set of callbacks (device ops) for both kernel virtio driver
(through virtio-mdev) or userspace virtio driver (through vhost-mdev).
>
> Does this mean this patch series is useful mostly for presenting virtio
> devices to containers or the host?
Patch 6 is mainly for bare metal or container use case, through it could
be used in guest as well. Patch 7 is a sample virtio mdev device
implementation. Patch 1 - 5 was the infrastructure for implementing
types other than vfio, the first user is virito-mdev, then Tiwei's
vhost-mdev and Parav's mlx5 mdev.
Thanks
>
> Stefan
next prev parent reply other threads:[~2019-10-17 1:43 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-11 8:15 [PATCH V3 0/7] mdev based hardware virtio offloading support Jason Wang
2019-10-11 8:15 ` [PATCH V3 1/7] mdev: class id support Jason Wang
2019-10-15 10:26 ` Cornelia Huck
2019-10-15 12:12 ` Jason Wang
2019-10-15 16:38 ` Alex Williamson
2019-10-16 4:38 ` Jason Wang
2019-10-16 4:57 ` Parav Pandit
2019-10-16 10:37 ` Jason Wang
2019-10-17 8:27 ` Jason Wang
2019-10-11 8:15 ` [PATCH V3 2/7] mdev: bus uevent support Jason Wang
2019-10-15 10:27 ` Cornelia Huck
2019-10-15 12:13 ` Jason Wang
2019-10-16 5:06 ` Parav Pandit
2019-10-11 8:15 ` [PATCH V3 3/7] modpost: add support for mdev class id Jason Wang
2019-10-11 8:15 ` [PATCH V3 4/7] mdev: introduce device specific ops Jason Wang
2019-10-15 10:41 ` Cornelia Huck
2019-10-15 12:17 ` Jason Wang
2019-10-15 17:26 ` Alex Williamson
2019-10-11 8:15 ` [PATCH V3 5/7] mdev: introduce virtio device and its device ops Jason Wang
2019-10-14 17:23 ` Stefan Hajnoczi
2019-10-15 3:27 ` Jason Wang
2019-10-11 8:15 ` [PATCH V3 6/7] virtio: introduce a mdev based transport Jason Wang
2019-10-14 17:39 ` Stefan Hajnoczi
2019-10-15 3:29 ` Jason Wang
2019-10-11 8:15 ` [PATCH V3 7/7] docs: sample driver to demonstrate how to implement virtio-mdev framework Jason Wang
2019-10-14 17:49 ` [PATCH V3 0/7] mdev based hardware virtio offloading support Stefan Hajnoczi
2019-10-15 3:37 ` Jason Wang
2019-10-15 14:37 ` Stefan Hajnoczi
2019-10-17 1:42 ` Jason Wang [this message]
2019-10-17 9:43 ` Stefan Hajnoczi
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