#! /bin/bash

# Note that usermode networking supports TCP and UDP but not ICMP.  In
# particular, ping will not work.

# Useful hint: Sometimes it's nice to pass the "-snapshot" argument

# Note: requires "modprobe kvm-intel"
# which loads "kvm" as well as "kvm-intel"

if test -z "${USB}" ; then
  1>&2 echo "Please export USB=/dev/something"
  exit 1
fi

mounted=$( awk '{
  if (match($1, "^'"${USB}"'") ) printf "%s ", $1;
}' /proc/mounts )

if test -n "$mounted" ; then
  1>&2 echo "You probably want to unmount some stuff:"
  for part in $mounted ; do
    1>&2 echo "  :; umount $part"
  done
  exit 1
fi

if ! lsmod | grep -w -q '^kvm_intel' ; then
  1>&2 echo 'Requires KVM modules.'
  1>&2 echo 'Hint:    sudo modprobe kvm_intel'
  exit 1
fi

qemu-system-x86_64              \
        -hda ${USB}             \
        -boot order=c           \
        -enable-kvm             \
        -m 1024M                \
        -rtc base=utc           \
        -object rng-random,filename=/dev/urandom,id=rng0        \
           -device virtio-rng-pci,rng=rng0      \
        "$@"