Re: [dpdk-dev] [PATCH 08/40] net/virtio: force IOVA as VA mode for Virtio-user

[Maxime Coquelin]

On 1/6/21 10:06 AM, David Marchand wrote:
> On Sun, Dec 20, 2020 at 10:14 PM Maxime Coquelin
> <maxime.coque...@redhat.com> wrote:
>> diff --git a/drivers/net/virtio/virtio_user_ethdev.c 
>> b/drivers/net/virtio/virtio_user_ethdev.c
>> index 1f1f63a1a5..f4775ff141 100644
>> --- a/drivers/net/virtio/virtio_user_ethdev.c
>> +++ b/drivers/net/virtio/virtio_user_ethdev.c
>> @@ -663,6 +663,17 @@ virtio_user_pmd_probe(struct rte_vdev_device *vdev)
>>         char *mac_addr = NULL;
>>         int ret = -1;
>>
>> +       /*
>> +        * ToDo 1: Implement detection mechanism at vdev bus level as PCI, 
>> but
>> +        * it implies API breakage.
> 
> Extending rte_vdev_driver to implement this detection would be an ABI 
> breakage.
> This is a driver-only API (rte_vdev_driver is only used by the vdev
> bus and drivers afaics).
> 
> Doing this is allowed as per my understanding of the ABI policy which
> guarantees ABI stability for applications.
> We do not guarantee this stability for OOT drivers.
> 

That would be a good news, as it would remove impacting the user by
requiring him to manually add --iova-mode=va in the EAL parameters.

I can change this in the v2 if this is confirmed. Ray, Thomas, is that
OK for you?

Thanks,
Maxime