Add support for specifying CD iso image to mount in virtual machines.

ansible/roles/bhyve/files/bhyve_netgraph_bridge.bash

@@ -48,6 +48,7 @@ function start_vm {
     host_interface_name="$4"
     bridge_name="bridge_${host_interface_name}"
     ip_range="$5"
+    mount_cd="${6:-}"
 
     mac_address=$(calculate_mac_address "$name")
 
@@ -66,6 +67,10 @@ function start_vm {
             # -s 29,fbuf,tcp=0.0.0.0:5900,w=1920,h=1080 \
 
     # TODO: Look into using nmdm instead of stdio for serial console
+    additional_args=()
+    if [ -n "$mount_cd" ]; then
+        additional_args+=("-s" "3,ahci-cd,$mount_cd")
+    fi
     while true; do
         set -x
         set +e
@@ -80,6 +85,7 @@ function start_vm {
             -s 30,xhci,tablet \
             -s 31,lpc -l com1,stdio \
             -l "bootrom,/usr/local/share/uefi-firmware/BHYVE_UEFI.fd,${mount_path}/BHYVE_UEFI_VARS.fd" \
+            "${additional_args[@]}" \
             "$name"
         exit_code=$?
         set -e