Add --guestfwd arg to boco boot

src/qemu.rs

@@ -24,6 +24,10 @@ pub struct BootCmd {
     #[clap(long)]
     forward: Vec<PortForward>,
 
+    /// Pass a `guestfwd=...` argument to qemu `-nic` argument.
+    #[clap(long)]
+    guestfwd: Vec<String>,
+
     /// Override the command to exec in the VM (base64-encoded on the kernel
     /// cmdline as `boco.cmd=<b64>`). Overrides the CMD inferred at build time.
     #[clap(long)]
@@ -49,6 +53,7 @@ pub(crate) fn boot(
         name,
         memory,
         forward,
+        guestfwd,
         cmd,
         mount,
         extra,
@@ -153,6 +158,9 @@ pub(crate) fn boot(
     for forward in &forward {
         _ = write!(&mut network, ",hostfwd={forward}");
     }
+    for guestfwd in &guestfwd {
+        _ = write!(&mut network, ",guestfwd={guestfwd}");
+    }
 
     let mut command = Command::new("qemu-system-x86_64");