Linux Virtualization - Nov 2019 - [PATCH V10 6/6] docs: sample driver to demonstrate how to implement virtio-mdev framework

On Thu, Nov 07, 2019 at 08:43:29PM +0800, Jason Wang
wrote:
> 
> On 2019/11/7 ??7:21, Michael S. Tsirkin wrote:
> > On Thu, Nov 07, 2019 at 06:18:45PM +0800, Jason Wang wrote:
> > > On 2019/11/7 ??5:08, Michael S. Tsirkin wrote:
> > > > On Wed, Nov 06, 2019 at 09:35:31PM +0800, Jason Wang wrote:
> > > > > This sample driver creates mdev device that simulate
virtio net device
> > > > > over virtio mdev transport. The device is implemented
through vringh
> > > > > and workqueue. A device specific dma ops is to make
sure HVA is used
> > > > > directly as the IOVA. This should be sufficient for
kernel virtio
> > > > > driver to work.
> > > > > 
> > > > > Only 'virtio' type is supported right now. I
plan to add 'vhost' type
> > > > > on top which requires some virtual IOMMU implemented in
this sample
> > > > > driver.
> > > > > 
> > > > > Acked-by: Cornelia Huck<cohuck at redhat.com>
> > > > > Signed-off-by: Jason Wang<jasowang at redhat.com>
> > > > I'd prefer it that we call this something else, e.g.
> > > > mvnet-loopback. Just so people don't expect a fully
> > > > functional device somehow. Can be renamed when applying?
> > > Actually, I plan to extend it as another standard network
interface for
> > > kernel. It could be either a standalone pseudo device or a stack
device.
> > > Does this sounds good to you?
> > > 
> > > Thanks
> > That's a big change in an interface so it's a good reason
> > to rename the driver at that point right?
> > Oherwise users of an old kernel would expect a stacked driver
> > and get a loopback instead.
> > 
> > Or did I miss something?
> 
> 
> My understanding is that it was a sample driver in /doc. It should not be
> used in production environment. Otherwise we need to move it to
> driver/virtio.
> 
> But if you insist, I can post a V11.
> 
> Thanks
this can be a patch on top.

On 2019/11/7 ??9:08, Michael S. Tsirkin wrote:
> On Thu, Nov 07, 2019 at 08:43:29PM +0800, Jason Wang wrote:
>> On 2019/11/7 ??7:21, Michael S. Tsirkin wrote:
>>> On Thu, Nov 07, 2019 at 06:18:45PM +0800, Jason Wang wrote:
>>>> On 2019/11/7 ??5:08, Michael S. Tsirkin wrote:
>>>>> On Wed, Nov 06, 2019 at 09:35:31PM +0800, Jason Wang wrote:
>>>>>> This sample driver creates mdev device that simulate
virtio net device
>>>>>> over virtio mdev transport. The device is implemented
through vringh
>>>>>> and workqueue. A device specific dma ops is to make
sure HVA is used
>>>>>> directly as the IOVA. This should be sufficient for
kernel virtio
>>>>>> driver to work.
>>>>>>
>>>>>> Only 'virtio' type is supported right now. I
plan to add 'vhost' type
>>>>>> on top which requires some virtual IOMMU implemented in
this sample
>>>>>> driver.
>>>>>>
>>>>>> Acked-by: Cornelia Huck<cohuck at redhat.com>
>>>>>> Signed-off-by: Jason Wang<jasowang at redhat.com>
>>>>> I'd prefer it that we call this something else, e.g.
>>>>> mvnet-loopback. Just so people don't expect a fully
>>>>> functional device somehow. Can be renamed when applying?
>>>> Actually, I plan to extend it as another standard network
interface for
>>>> kernel. It could be either a standalone pseudo device or a
stack device.
>>>> Does this sounds good to you?
>>>>
>>>> Thanks
>>> That's a big change in an interface so it's a good reason
>>> to rename the driver at that point right?
>>> Oherwise users of an old kernel would expect a stacked driver
>>> and get a loopback instead.
>>>
>>> Or did I miss something?
>>
>> My understanding is that it was a sample driver in /doc. It should not
be
>> used in production environment. Otherwise we need to move it to
>> driver/virtio.
>>
>> But if you insist, I can post a V11.
>>
>> Thanks
> this can be a patch on top.

Then maybe it's better just extend it to work as a normal networking 
device on top?

Thanks

On Thu, Nov 07, 2019 at 09:32:29PM +0800, Jason Wang
wrote:
> 
> On 2019/11/7 ??9:08, Michael S. Tsirkin wrote:
> > On Thu, Nov 07, 2019 at 08:43:29PM +0800, Jason Wang wrote:
> > > On 2019/11/7 ??7:21, Michael S. Tsirkin wrote:
> > > > On Thu, Nov 07, 2019 at 06:18:45PM +0800, Jason Wang wrote:
> > > > > On 2019/11/7 ??5:08, Michael S. Tsirkin wrote:
> > > > > > On Wed, Nov 06, 2019 at 09:35:31PM +0800, Jason
Wang wrote:
> > > > > > > This sample driver creates mdev device that
simulate virtio net device
> > > > > > > over virtio mdev transport. The device is
implemented through vringh
> > > > > > > and workqueue. A device specific dma ops is
to make sure HVA is used
> > > > > > > directly as the IOVA. This should be
sufficient for kernel virtio
> > > > > > > driver to work.
> > > > > > > 
> > > > > > > Only 'virtio' type is supported right
now. I plan to add 'vhost' type
> > > > > > > on top which requires some virtual IOMMU
implemented in this sample
> > > > > > > driver.
> > > > > > > 
> > > > > > > Acked-by: Cornelia Huck<cohuck at
redhat.com>
> > > > > > > Signed-off-by: Jason Wang<jasowang at
redhat.com>
> > > > > > I'd prefer it that we call this something
else, e.g.
> > > > > > mvnet-loopback. Just so people don't expect a
fully
> > > > > > functional device somehow. Can be renamed when
applying?
> > > > > Actually, I plan to extend it as another standard
network interface for
> > > > > kernel. It could be either a standalone pseudo device
or a stack device.
> > > > > Does this sounds good to you?
> > > > > 
> > > > > Thanks
> > > > That's a big change in an interface so it's a good
reason
> > > > to rename the driver at that point right?
> > > > Oherwise users of an old kernel would expect a stacked
driver
> > > > and get a loopback instead.
> > > > 
> > > > Or did I miss something?
> > > 
> > > My understanding is that it was a sample driver in /doc. It
should not be
> > > used in production environment. Otherwise we need to move it to
> > > driver/virtio.
> > > 
> > > But if you insist, I can post a V11.
> > > 
> > > Thanks
> > this can be a patch on top.
> 
> 
> Then maybe it's better just extend it to work as a normal networking
device
> on top?
> 
> Thanks
That would be a substantial change. Maybe drop 6/6 for now until
we have a better handle on this?