vmm, hypervisor: Initialize SEV-SNP VM

As part of this initialization for a SEV-SNP VM on MSHV, it is required
that we transition the guest state to secure state using partition
hypercall. This implies all the created VPs will transition to secure
state and could access the guest encrypted memory.

Signed-off-by: Jinank Jain <jinankjain@microsoft.com>

hypervisor/src/mshv/mod.rs

@@ -1266,4 +1266,14 @@ impl vm::Vm for MshvVm {
     fn as_any(&self) -> &dyn Any {
         self
     }
+    /// Initialize the SEV-SNP VM
+    #[cfg(feature = "sev_snp")]
+    fn sev_snp_init(&self) -> vm::Result<()> {
+        self.fd
+            .set_partition_property(
+                hv_partition_property_code_HV_PARTITION_PROPERTY_ISOLATION_STATE,
+                hv_partition_isolation_state_HV_PARTITION_ISOLATION_SECURE as u64,
+            )
+            .map_err(|e| vm::HypervisorVmError::InitializeSevSnp(e.into()))
+    }
 }