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 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?
> 
> > 
> >

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

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 08:43:29PM +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.