From: Thomas Falcon <redacted>
Date: Mon, 12 Aug 2019 10:56:39 -0500

Hi, thanks for reporting this. I was able to recreate this on my own
system. The virtual ethernet's multicast filter list size is limited,
and the driver will check that there is available space before adding
entries.  The problem is that the size is encoded as big endian, but
the driver does not convert it for little endian systems after
retrieving it from the device tree.  As a result the driver is
requesting more than the hypervisor can allow and getting this error
in reply. I will submit a patch to correct this soon.

This is 1,000 times better than just trying to make the warning message
go away, thanks Thomas!