Since commit 2566378d6d13bf4d28c7770bdbda5f7682594bbe, libvhost-user
no longer panics on disconnect (rc == 0), and instead silently ignores
an invalid VHOST_USER_NONE message.

Without extra work from the API user, this will simply busy-loop on
HUP events. The obvious thing to do is to exit(0) instead, while
additional or different work can be done by overriding
iface->process_msg().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Jens Freimann <jfreimann@redhat.com>
---
 contrib/libvhost-user/libvhost-user.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/contrib/libvhost-user/libvhost-user.c b/contrib/libvhost-user/libvhost-user.c
index 3f14b4138b..fcf5014240 100644
--- a/contrib/libvhost-user/libvhost-user.c
+++ b/contrib/libvhost-user/libvhost-user.c
@@ -1285,7 +1285,8 @@ vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
     case VHOST_USER_SET_CONFIG:
         return vu_set_config(dev, vmsg);
     case VHOST_USER_NONE:
-        break;
+        /* if you need processing before exit, override iface->process_msg */
+        exit(0);
     case VHOST_USER_POSTCOPY_ADVISE:
         return vu_set_postcopy_advise(dev, vmsg);
     case VHOST_USER_POSTCOPY_LISTEN:
-- 
2.21.0