[dpdk-dev] [PATCH v2 2/5] net/virtio: add interrupt configure for vdev

[Tan, Jianfeng]

On 3/29/2017 3:09 PM, Yuanhan Liu wrote:
> On Wed, Mar 29, 2017 at 03:03:16PM +0800, Tan, Jianfeng wrote:
>>
>> On 3/29/2017 2:27 PM, Yuanhan Liu wrote:
>>> On Tue, Mar 28, 2017 at 08:21:53AM +0000, Jianfeng Tan wrote:
>>>> For virtio PCI devices, interrupt should be configured before setting
>>>> VIRTIO_CONFIG_STATUS_DRIVER_OK so that QEMU can properly set eventfds
>>>> in the host.
>>>>
>>>> For virtio virtual devices, VIRTIO_CONFIG_STATUS_DRIVER_OK should be
>>>> set firstly, so that intr_handle is initialized in
>>>> virtio_user_start_device().
>>> I'm wondering why can't you let virtio-user follow virtio-pci?
>> It's because that virtio-user not only counts on virtio_user_start_device()
>> to allocate intr_handle, it also needs the information in this function to
>> initialize this struct. For virtio-pci, similar information is from
>> rte_intr_enable/rte_intr_efd_enable.
>>
>> Or do you mean we can move calling virtio_user_start_device() ahead? I can
>> hardly find other place instead of DRIVER_OK.
> For example, virtio_user_dev_init()?
>
>
But in that way, there is only one chance to negotiate features with the 
backend. What if we change the configuration through 
rte_eth_dev_configure()?

Yes, we can just put callfd/kickfd creation and intr_handle 
initialization into virtio_user_dev_init(), and its destructor into 
virtio_user_dev_uninit(). It sounds like a feasible way to go.

Thanks,
Jianfeng