Add support for virtio-9p

quickemu

@@ -467,6 +467,17 @@ function vm_boot() {
     if [ "${guest_os}" != "macos" ]; then
       echo " - WebDAV:   ${PUBLIC} via: dav://localhost:9843/"
     fi
+
+    if [ "${guest_os}" != "windows" ]; then
+      echo -n " - 9P:       ${PUBLIC} via: "
+      if [ "${guest_os}" == "linux" ]; then
+        echo "sudo mount -t 9p -o trans=virtio,version=9p2000.L,msize=104857600 ${USER}-public ~/Public"
+      elif [ "${guest_os}" == "macos" ]; then
+        # PUBLICSHARE needs to be world writeable for seamless integration with
+        # macOS. Test if it is is world writeable, and prompt what to do if not.
+        echo "sudo mount_9p ${USER}-public"
+      fi
+    fi
   fi
 
   enable_usb_passthrough
@@ -565,6 +576,14 @@ function vm_boot() {
           -object rng-random,id=rng0,filename=/dev/urandom)
   fi
 
+  # https://wiki.qemu.org/Documentation/9psetup
+  # https://askubuntu.com/questions/772784/9p-libvirt-qemu-share-modes
+  if [ "${guest_os}" != "windows" ]; then
+      # shellcheck disable=SC2054
+      args+=(-fsdev local,id=fsdev0,path="${PUBLIC}",security_model=mapped-xattr
+             -device virtio-9p-pci,fsdev=fsdev0,mount_tag="${USER}-public")
+  fi
+
   if [ -n "${USB_PASSTHROUGH}" ]; then
     # shellcheck disable=SC2054,SC2206
     args+=(-device ${USB_HOST_PASSTHROUGH_CONTROLLER},id=hostpass