Under a NetBSD 6.1.2/amd64 and Xen 4.2.3, FreeBSD 10.0-ALPHA5 network is unstable/unusable.

Trying to ssh in to the virtual machine does not work.

On the first attempt, ssh from the client hung in connect() and at the
FreeBSD domU console there was a panic[1].

On the dom0 console, the following was shown:
xvif3i0: packet size 1610 too big
xvif3i0: packet size 0 too big
xvif3i0: packet size 1544 too big


Disabling txcsum and rxcsum[2] makes the client hang in select() instead,
but on the FreeBSD we still see "xn_txeof: WARNING: response is -1!",
while simultaneously on the dom0 the following is printed to the system
console: "xvif5i0: packet cross page boundary". The SSH connection is of
course never established.
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[1] https://webmail.ami.org.pt/panic.jpg
[2] http://lists.freebsd.org/pipermail/freebsd-xen/2011-May/000940.html --
    I saw & reported this same error on 9.x two years ago. It was fixed.
    Also, I run a 10-CURRENT snapshot from maybe half a year ago and
    everything works as expected there as well.