vmm: cpu: Introduce concept of maximum vs boot vCPUs in CpuManager

For now the max vCPUs is the same as the boot vCPUs.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/cpu.rs

@@ -336,6 +336,7 @@ impl Vcpu {
 
 pub struct CpuManager {
     boot_vcpus: u8,
+    max_vcpus: u8,
     io_bus: Weak<devices::Bus>,
     mmio_bus: Arc<devices::Bus>,
     ioapic: Option<Arc<Mutex<ioapic::Ioapic>>>,
@@ -388,6 +389,7 @@ impl BusDevice for CpuManager {
 impl CpuManager {
     pub fn new(
         boot_vcpus: u8,
+        max_vcpus: u8,
         device_manager: &DeviceManager,
         guest_memory: Arc<RwLock<GuestMemoryMmap>>,
         fd: Arc<VmFd>,
@@ -396,6 +398,7 @@ impl CpuManager {
     ) -> Result<Arc<Mutex<CpuManager>>> {
         let cpu_manager = Arc::new(Mutex::new(CpuManager {
             boot_vcpus,
+            max_vcpus,
             io_bus: Arc::downgrade(&device_manager.io_bus().clone()),
             mmio_bus: device_manager.mmio_bus().clone(),
             ioapic: device_manager.ioapic().clone(),
@@ -568,4 +571,12 @@ impl CpuManager {
         }
         Ok(())
     }
+
+    pub fn boot_vcpus(&self) -> u8 {
+        self.boot_vcpus
+    }
+
+    pub fn max_vcpus(&self) -> u8 {
+        self.max_vcpus
+    }
 }

vmm/src/vm.rs

@@ -451,8 +451,10 @@ impl Vm {
         let on_tty = unsafe { libc::isatty(libc::STDIN_FILENO as i32) } != 0;
 
         let boot_vcpus = config.cpus.cpu_count;
+        let max_vcpus = config.cpus.cpu_count;
         let cpu_manager = cpu::CpuManager::new(
             boot_vcpus,
+            max_vcpus,
             &device_manager,
             guest_memory.clone(),
             fd,