NFS mount from Qemu guest?

[Andrew Klaassen]

I've been trying to get an NFS share mounted on a Qemu guest from an NFS server 
which does not allow connections from unprivileged ports.

I have tried a bunch of different guestfwd options, thinking that they might 
help me get my outgoing connections from the guest back down into the 
privileged port range, but so far no luck.

Here's the basic command I'm running.  It's based on the Qemu command generated 
by Packer, which is what I'm ultimately trying to get working:

/usr/local/bin/qemu-system-x86_64 -serial stdio -boot once=d -drive 
file=v001.qcow2,if=virtio,cache=writeback,discard=ignore,format=qcow2 -drive 
file=systemrescue-11.01-amd64.iso,media=cdrom -m 2048M -vnc 127.0.0.1:33 -cpu 
host -smp 1 -name packer-centos7 -device virtio-net,netdev=user.0 -machine 
type=pc,accel=kvm -netdev user,id=user.0,hostfwd=tcp::2262-:22,guestfwd=

For the guestfwd= clause, I've tried things like:

guestfwd=tcp:10.0.2.100:111-cmd:netcat 10.31.32.15 
111,guestfwd=tcp:10.0.2.100:2049-cmd:netcat 10.31.32.15 
2049,guestfwd=tcp:10.0.2.100:300-cmd:netcat 10.31.32.15 300
...the outgoing connections still come from unprivileged ports

guestfwd=tcp:0.0.0.0:700-tcp:10.0.2.2:700
...with "sysctl -w sunrpc.min_resvport=700; sysctl -w sunrpc.max_resvport=700" 
in the guest before trying the NFS mount
...same, outgoing connections still come from unprivileged ports

guestfwd=tcp:<nfs server ip>:700-tcp:10.0.2.2:700
...this one breaks VNC for some reason and I can't reach the guest to try 
anything

There are a bunch of other random things I've tried, too.  I obviously don't 
understand what I'm doing.  Does anybody have a recipe for making this work?  
Is guestfwd even the correct option to use for this?

Thanks.

Andrew