Re: [Qemu-devel] [PATCH] virtio/vhost: drop unnecessary VHOST_SET_VRING call

[Marcel Apfelbaum <marcel@redhat.com>]

On 08/12/2015 01:34 PM, Michael S. Tsirkin wrote:
> On Wed, Aug 12, 2015 at 01:19:51PM +0300, Marcel Apfelbaum wrote:
>> No need to send VHOST_SET_VRING_CALL to backend
>> before the negotiation with the guest is finished.
>>
>> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
>
> Well - we do need to set it to the masked notifier initially to avoid
> losing events.  You can't just drop it - need to move this call
> somewhere else.
What do we need to set?
I just dropped the call to VHOST_SET_VRING_CALL.

Thanks,
Marcel

>
>> ---
>>   hw/virtio/vhost.c | 13 +------------
>>   1 file changed, 1 insertion(+), 12 deletions(-)
>>
>> diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
>> index 2712c6f..b448542 100644
>> --- a/hw/virtio/vhost.c
>> +++ b/hw/virtio/vhost.c
>> @@ -875,24 +875,13 @@ static void vhost_eventfd_del(MemoryListener *listener,
>>   static int vhost_virtqueue_init(struct vhost_dev *dev,
>>                                   struct vhost_virtqueue *vq, int n)
>>   {
>> -    struct vhost_vring_file file = {
>> -        .index = n,
>> -    };
>>       int r = event_notifier_init(&vq->masked_notifier, 0);
>> +
>>       if (r < 0) {
>>           return r;
>>       }
>>
>> -    file.fd = event_notifier_get_fd(&vq->masked_notifier);
>> -    r = dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_CALL, &file);
>> -    if (r) {
>> -        r = -errno;
>> -        goto fail_call;
>> -    }
>>       return 0;
>> -fail_call:
>> -    event_notifier_cleanup(&vq->masked_notifier);
>> -    return r;
>>   }
>>
>>   static void vhost_virtqueue_cleanup(struct vhost_virtqueue *vq)
>> --
>> 2.1.0