cloud-hypervisor: Add the --cpus option

You guessed it: To specify the number of vcpus.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

src/main.rs

@@ -25,6 +25,12 @@ fn main() {
                 .help("Path to kernel image (vmlinux)")
                 .takes_value(true),
         )
+        .arg(
+            Arg::with_name("cpus")
+                .long("cpus")
+                .help("Number of virtual CPUs")
+                .takes_value(true),
+        )
         .get_matches();
 
     let kernel_arg = cmd_arguments
@@ -34,9 +40,15 @@ fn main() {
 
     let kernel_path = kernel_arg.as_path();
 
+    let mut vcpus = DEFAULT_VCPUS;
+    if let Some(cpus) = cmd_arguments.value_of("cpus") {
+        vcpus = cpus.parse::<u8>().unwrap();
+    }
+
+    println!("VM [{} vCPUS]", vcpus);
     println!("Booting {:?}...", kernel_path);
 
-    let vm_config = VmConfig::new(kernel_path).unwrap();
+    let vm_config = VmConfig::new(kernel_path, vcpus).unwrap();
 
     vmm::boot_kernel(vm_config).unwrap();
 }

vmm/src/vm.rs

@@ -168,9 +168,10 @@ pub struct VmConfig<'a> {
 }
 
 impl<'a> VmConfig<'a> {
-    pub fn new(kernel_path: &'a Path) -> Result<Self> {
+    pub fn new(kernel_path: &'a Path, vcpus: u8) -> Result<Self> {
         Ok(VmConfig {
             kernel_path,
+            vcpu_count: vcpus,
             ..Default::default()
         })
     }