Re: [PATCH V4 3/5] vDPA: introduce vDPA bus

On 2020/2/24 下午2:14, Harpreet Singh Anand wrote:

Is there a plan to add an API in vDPA_config_ops for getting the notification area from the VDPA device (something similar to get_notify_area in the VDPA DPDK case)? This will make the notifications from the guest  (vhost_vdpa use case) to the VDPA device more efficient - at least for virtio 1.0+ drivers in the VM.

I believe this would require enhancement to the vhost ioctl (something similar to the  VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG).

Yes, we plan to add that on top. Basically, here's what we plan to do: 
(sorted by urgency)

1) direct doorbell mapping as you asked here
2) direct interrupt injection (when platform support, e.g through posted 
interrupt)
3) control virtqueue support

Thanks

Regards,
Harpreet