Add a new option for iommufd, The usage is
....
-object iommufd,id=iommufd0 \
-device virtio-net-pci,netdev=vhost-vdpa1,disable-legacy=on,disable-modern=off\
-netdev type=vhost-vdpa,vhostdev=/dev/vhost-vdpa-0,id=vhost-vdpa1,iommufd=iommufd0\
...

Signed-off-by: Cindy Lu <lulu@redhat.com>
---
 qapi/net.json | 1 +
 1 file changed, 1 insertion(+)

diff --git a/qapi/net.json b/qapi/net.json
index 522ac582ed..fffaf9bb5e 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -461,6 +461,7 @@
     '*vhostdev':     'str',
     '*vhostfd':      'str',
     '*queues':       'int',
+    '*iommufd':       'str',
     '*x-svq':        {'type': 'bool', 'features' : [ 'unstable'] } } }
 
 ##
-- 
2.34.3