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

On 2019/11/7 ??8:43, 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 

Or maybe it's better to rename the type of current mdev from
'virtio' to
'virtio-loopback'. Then we can add more types in the future.

Thanks

On Thu, Nov 07, 2019 at 08:47:06PM +0800, Jason Wang
wrote:
> 
> On 2019/11/7 ??8:43, 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
> 
> 
> Or maybe it's better to rename the type of current mdev from
'virtio' to
> 'virtio-loopback'. Then we can add more types in the future.
> 
> Thanks
> 
Maybe but is virtio actually a loopback somehow? I thought we
can bind a regular virtio device there, no?

-- 
MST

On 2019/11/7 ??9:08, Michael S. Tsirkin wrote:
> On Thu, Nov 07, 2019 at 08:47:06PM +0800, Jason Wang wrote:
>> On 2019/11/7 ??8:43, 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
>>
>> Or maybe it's better to rename the type of current mdev from
'virtio' to
>> 'virtio-loopback'. Then we can add more types in the future.
>>
>> Thanks
>>
> Maybe but is virtio actually a loopback somehow? I thought we
> can bind a regular virtio device there, no?

It has a prefix, so user will see "mvnet-virtio-loopback".

Thanks
>