vmm: vm: Validate configuration on API boot

When performing an API boot validate the configuration. For now only
some very basic validation is performed but in subsequent commits
the validation will be extended.

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

vmm/src/vm.rs

@@ -25,7 +25,9 @@ extern crate vm_allocator;
 extern crate vm_memory;
 extern crate vm_virtio;
 
-use crate::config::{DeviceConfig, DiskConfig, HotplugMethod, NetConfig, PmemConfig, VmConfig};
+use crate::config::{
+    DeviceConfig, DiskConfig, HotplugMethod, NetConfig, PmemConfig, ValidationError, VmConfig,
+};
 use crate::cpu;
 use crate::device_manager::{get_win_size, Console, DeviceManager, DeviceManagerError};
 use crate::memory_manager::{Error as MemoryManagerError, MemoryManager};
@@ -191,6 +193,9 @@ pub enum Error {
 
     /// Cannot convert source URL from Path into &str
     RestoreSourceUrlPathToStr,
+
+    /// Failed to validate config
+    ConfigValidation(ValidationError),
 }
 pub type Result<T> = result::Result<T, Error>;
 
@@ -309,6 +314,12 @@ impl Vm {
         reset_evt: EventFd,
         vmm_path: PathBuf,
     ) -> Result<Self> {
+        config
+            .lock()
+            .unwrap()
+            .validate()
+            .map_err(Error::ConfigValidation)?;
+
         let device_manager = DeviceManager::new(
             fd.clone(),
             config.clone(),