chore: set up QEMU env.

.gitignore

@@ -15,3 +15,7 @@
 
 # If the VM crashes, it generates a dump, let's ignore it too.
 erl_crash.dump
+
+# Test drive images.
+/tmp
+*.img

config/target.exs

@@ -66,7 +66,7 @@ config :mdns_lite,
   # because otherwise any of the devices may respond to nerves.local leading to
   # unpredictable behavior.
 
-  hosts: [:hostname, "nerves"],
+  hosts: [:hostname, "bivouac"],
   ttl: 120,
 
   # Advertise the following services over mDNS.

run-qemu.sh

@@ -0,0 +1,38 @@
+#!/bin/sh
+
+#
+# Run a nerves_system_x86_64-based image in QEMU
+#
+# Usage:
+#   run-qemu.sh [Path to .img file]
+#
+
+set -e
+
+IMAGE="$1"
+DEFAULT_IMAGE="bivouac.img"
+
+help() {
+    echo
+    echo "Usage:"
+    echo "  run-qemu.sh [Path to .img file]"
+    echo
+    echo "Run 'mix firmware.image' to create the starter image. Since qemu isn't"
+    echo "supported by Nerves, we don't have instructions for how to make this a"
+    echo "productive development environment. You should be able to see this"
+    echo "boot, though."
+    exit 1
+}
+[ -n "$IMAGE" ] || IMAGE="$DEFAULT_IMAGE"
+
+[ -f "$IMAGE" ] || (echo "Error: can't find '$IMAGE'"; help)
+
+echo "Starting QEMU..."
+qemu-system-x86_64 \
+    -drive file="$IMAGE",if=virtio,format=raw \
+    -drive file="tmp/disk0.img",if=virtio,format=raw \
+    -drive file="tmp/disk1.img",if=virtio,format=raw \
+    -drive file="tmp/disk2.img",if=virtio,format=raw \
+    -net nic,model=virtio \
+    -net user,hostfwd=tcp::10022-:22 \
+    -serial stdio