From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: errors from VHOST on shutdown.
Date: Tue, 23 Oct 2018 08:56:58 -0700
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To: Maxime Coquelin <maxime.coquelin@redhat.com>, Tiwei Bie
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I get errors on shutdown of application using virtio-user.
For example, quitting testpmd:

Detaching a port...
vhost_kernel_set_backend(): VHOST_NET_SET_BACKEND fails, Operation not permitted
vhost_kernel_set_backend(): VHOST_NET_SET_BACKEND fails, Operation not permitted
vhost_kernel_ioctl(): VHOST_RESET_OWNER failed: Operation not permitted

Everything works fine, but not good to have this kind of thing visible to user.
These error messages should be fixed, or the error message removed.

How do you want to handle it?