Re: [Qemu-arm] [PATCH V2] virtio: Fix no interrupt when not creating msi controller

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jan 23, 2017 at 08:55:04AM +0800, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@linaro.org>
> 
> For ARM virt machine, if we use virt-2.7 which will not create ITS node,
> the virtio-net can not recieve interrupts so it can't get ip address
> through dhcp.
> This fixes commit 83d768b(virtio: set ISR on dataplane notifications).
> 
> Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>

Paolo, could you comment on this pls?


> ---
> V2: Factor out a common function instead of duplicating code
> ---
>  hw/virtio/virtio.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index aa4f38f..00e8f74 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -1441,6 +1441,12 @@ void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
>      event_notifier_set(&vq->guest_notifier);
>  }
>  
> +static void virtio_irq(VirtQueue *vq)
> +{
> +    virtio_set_isr(vq->vdev, 0x1);
> +    virtio_notify_vector(vq->vdev, vq->vector);
> +}
> +
>  void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
>  {
>      if (!virtio_should_notify(vdev, vq)) {
> @@ -1448,8 +1454,7 @@ void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
>      }
>  
>      trace_virtio_notify(vdev, vq);
> -    virtio_set_isr(vq->vdev, 0x1);
> -    virtio_notify_vector(vdev, vq->vector);
> +    virtio_irq(vq);
>  }
>  
>  void virtio_notify_config(VirtIODevice *vdev)
> @@ -2082,7 +2087,7 @@ static void virtio_queue_guest_notifier_read(EventNotifier *n)
>  {
>      VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
>      if (event_notifier_test_and_clear(n)) {
> -        virtio_notify_vector(vq->vdev, vq->vector);
> +        virtio_irq(vq);
>      }
>  }
>  
> -- 
> 2.0.4
>