Re: [RFC PATCH] virtio_net: Extend virtio to use VF datapath when available

From: "Samudrala, Sridhar" <sridhar.samudrala@intel.com>
Date: Tue, 19 Dec 2017 09:41:39 -0800

This is based on netvsc implementation and here is the commit that
added this delay.  Not sure if this needs to be 100ms.

commit 6123c66854c174e4982f98195100c1d990f9e5e6
Author: stephen hemminger [off-list ref]
Date:   Wed Aug 9 17:46:03 2017 -0700

    netvsc: delay setup of VF device

    When VF device is discovered, delay bring it automatically up in
    order to allow userspace to some simple changes (like renaming).

This is kind of bogus, I should have called this out when the patch
was posted.

Any delay is wrong, there needs to be tight synchronization if a
userspace operation must occur before proceeding.  If something
happens and userspace is delayed, this whole thing doesn't work.