arch, pci, vmm: Initial switch to the hypervisor crate

Start moving the vmm, arch and pci crates to being hypervisor agnostic
by using the hypervisor trait and abstractions. This is not a complete
switch and there are still some remaining KVM dependencies.

Signed-off-by: Muminul Islam <muislam@microsoft.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

vmm/src/lib.rs

@@ -5,6 +5,7 @@
 
 extern crate anyhow;
 extern crate arc_swap;
+extern crate hypervisor;
 #[macro_use]
 extern crate lazy_static;
 #[macro_use]
@@ -213,6 +214,7 @@ pub fn start_vmm_thread(
     api_sender: Sender<ApiRequest>,
     api_receiver: Receiver<ApiRequest>,
     seccomp_level: &SeccompLevel,
+    hypervisor: Arc<dyn hypervisor::Hypervisor>,
 ) -> Result<thread::JoinHandle<Result<()>>> {
     let http_api_event = api_event.try_clone().map_err(Error::EventFdClone)?;
 
@@ -232,7 +234,7 @@ pub fn start_vmm_thread(
             // Apply seccomp filter for VMM thread.
             SeccompFilter::apply(vmm_seccomp_filter).map_err(Error::ApplySeccompFilter)?;
 
-            let mut vmm = Vmm::new(vmm_version.to_string(), api_event, vmm_path)?;
+            let mut vmm = Vmm::new(vmm_version.to_string(), api_event, vmm_path, hypervisor)?;
 
             vmm.control_loop(Arc::new(api_receiver))
         })
@@ -253,10 +255,16 @@ pub struct Vmm {
     vm: Option<Vm>,
     vm_config: Option<Arc<Mutex<VmConfig>>>,
     vmm_path: PathBuf,
+    hypervisor: Arc<dyn hypervisor::Hypervisor>,
 }
 
 impl Vmm {
-    fn new(vmm_version: String, api_evt: EventFd, vmm_path: PathBuf) -> Result<Self> {
+    fn new(
+        vmm_version: String,
+        api_evt: EventFd,
+        vmm_path: PathBuf,
+        hypervisor: Arc<dyn hypervisor::Hypervisor>,
+    ) -> Result<Self> {
         let mut epoll = EpollContext::new().map_err(Error::Epoll)?;
         let exit_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::EventFdCreate)?;
         let reset_evt = EventFd::new(EFD_NONBLOCK).map_err(Error::EventFdCreate)?;
@@ -286,6 +294,7 @@ impl Vmm {
             vm: None,
             vm_config: None,
             vmm_path,
+            hypervisor,
         })
     }
 
@@ -301,6 +310,7 @@ impl Vmm {
                     exit_evt,
                     reset_evt,
                     self.vmm_path.clone(),
+                    self.hypervisor.clone(),
                 )?;
                 self.vm = Some(vm);
             }
@@ -370,6 +380,7 @@ impl Vmm {
             self.vmm_path.clone(),
             source_url,
             restore_cfg.prefault,
+            self.hypervisor.clone(),
         )?;
         self.vm = Some(vm);
 
@@ -413,7 +424,13 @@ impl Vmm {
             if self.reset_evt.read().is_ok() {
                 warn!("Spurious second reset event received. Ignoring.");
             }
-            self.vm = Some(Vm::new(config, exit_evt, reset_evt, self.vmm_path.clone())?);
+            self.vm = Some(Vm::new(
+                config,
+                exit_evt,
+                reset_evt,
+                self.vmm_path.clone(),
+                self.hypervisor.clone(),
+            )?);
         }
 
         // Then we start the new VM.