vmm: Use a reference counted VmConfig when creating a new VM

Once passed to the VM creation routine, a VmConfig structure is
immutable. We can simply carry a Arc of it instead of a reference.
This also allows us to remove any lifetime bound from our VM.

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

src/main.rs

@@ -11,7 +11,7 @@ extern crate clap;
 use clap::{App, Arg};
 use log::LevelFilter;
 use std::process;
-use std::sync::Mutex;
+use std::sync::{Arc, Mutex};
 use vmm::config;
 
 struct Logger {
@@ -285,7 +285,7 @@ fn main() {
         vm_config.disks,
     );
 
-    if let Err(e) = vmm::start_vm_loop(vm_config) {
+    if let Err(e) = vmm::start_vm_loop(Arc::new(vm_config)) {
         println!("Guest boot failed: {}", e);
         process::exit(1);
     }

vmm/src/lib.rs

@@ -8,6 +8,7 @@ extern crate log;
 
 use std::fmt::{self, Display};
 use std::result;
+use std::sync::Arc;
 
 pub mod config;
 pub mod device_manager;
@@ -38,9 +39,9 @@ impl Display for Error {
     }
 }
 
-pub fn start_vm_loop(config: VmConfig) -> Result<()> {
+pub fn start_vm_loop(config: Arc<VmConfig>) -> Result<()> {
     loop {
-        let mut vm = Vm::new(&config).map_err(Error::VmNew)?;
+        let mut vm = Vm::new(config.clone()).map_err(Error::VmNew)?;
 
         if vm.start().map_err(Error::VmStart)? == ExitBehaviour::Shutdown {
             break;

vmm/src/vm.rs

@@ -503,14 +503,14 @@ pub enum ExitBehaviour {
     Reset = 2,
 }
 
-pub struct Vm<'a> {
+pub struct Vm {
     fd: Arc<VmFd>,
     kernel: File,
     memory: Arc<RwLock<GuestMemoryMmap>>,
     threads: Vec<thread::JoinHandle<()>>,
     devices: DeviceManager,
     cpuid: CpuId,
-    config: &'a VmConfig,
+    config: Arc<VmConfig>,
     epoll: EpollContext,
     on_tty: bool,
     creation_ts: std::time::Instant,
@@ -535,8 +535,8 @@ fn get_host_cpu_phys_bits() -> u8 {
     }
 }
 
-impl<'a> Vm<'a> {
-    pub fn new(config: &'a VmConfig) -> Result<Self> {
+impl Vm {
+    pub fn new(config: Arc<VmConfig>) -> Result<Self> {
         let kvm = Kvm::new().map_err(Error::KvmNew)?;
         let kernel = File::open(&config.kernel.path).map_err(Error::KernelFile)?;
         let fd = kvm.create_vm().map_err(Error::VmCreate)?;
@@ -717,7 +717,7 @@ impl<'a> Vm<'a> {
         let vm_info = VmInfo {
             memory: &guest_memory,
             vm_fd: &fd,
-            vm_cfg: config,
+            vm_cfg: &config,
         };
 
         let exit_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::EventFd)?;