Add a --memory flag

src/qemu.rs

@@ -2,12 +2,23 @@
 //! boot (-kernel/-initrd).
 
 use anyhow::{Context, Result, bail};
+use clap::Args;
 use std::process::Command;
 
 use crate::registry::registry_dir;
 
-pub(crate) fn run(name: &str) -> Result<()> {
-    let reg_dir = registry_dir(name)?;
+#[derive(Args, Debug)]
+pub struct RunCmd {
+    /// Image tag / registry subdir name
+    name: String,
+
+    /// Amount of memory to give the VM, in qemu's format.
+    #[clap(short, long, default_value = "1024M")]
+    memory: String,
+}
+
+pub(crate) fn run(RunCmd { name, memory }: RunCmd) -> Result<()> {
+    let reg_dir = registry_dir(&name)?;
     let vmlinuz_path = reg_dir.join("vmlinuz");
     let initrd_path = reg_dir.join("initrd");
     if !vmlinuz_path.exists() || !initrd_path.exists() {
@@ -16,7 +27,7 @@ pub(crate) fn run(name: &str) -> Result<()> {
             name
         );
     }
-    println!("Booting {} from registry: {}", name, reg_dir.display());
+    println!("Booting {name} from registry: {}", reg_dir.display());
     println!(
         "  qemu-system-x86_64 -m 256 -nographic -kernel {} -initrd {} -append 'console=ttyS0'",
         vmlinuz_path.display(),
@@ -35,7 +46,7 @@ pub(crate) fn run(name: &str) -> Result<()> {
 
     let mut command = Command::new("qemu-system-x86_64");
     command
-        .args(["-m", "1024M"])
+        .args(["-m", &memory])
         .arg("-kernel")
         .arg(vmlinuz_path.as_os_str())
         .arg("-initrd")