hypervisor: Introduce VM state to Vm hypervisor trait

We may need to store hypervisor speciific data to the VM. This support is
needed for Microsoft hyperv implementations. This patch introduces two
new definitions to Vm trait and implements for KVM.

Signed-off-by: Muminul Islam <muislam@microsoft.com>

hypervisor/src/vm.rs

@@ -14,6 +14,7 @@ use crate::cpu::Vcpu;
 use crate::device::Device;
 #[cfg(target_arch = "x86_64")]
 use crate::ClockData;
+use crate::KvmVmState as VmState;
 use crate::{CreateDevice, IoEventAddress, IrqRoutingEntry, MemoryRegion};
 use kvm_ioctls::Cap;
 use std::sync::Arc;
@@ -179,4 +180,8 @@ pub trait Vm: Send + Sync {
     fn check_extension(&self, c: Cap) -> bool;
     /// Create a device that is used for passthrough
     fn create_passthrough_device(&self) -> Result<Arc<dyn Device>>;
+    /// Get the Vm state. Return VM specific data
+    fn state(&self) -> Result<VmState>;
+    /// Set the VM state
+    fn set_state(&self, state: &VmState) -> Result<()>;
 }