hypervisor: Use instruction emulator to handle unmapped gpa

Use the context from Unmapped Gpa exit from the hypervisor to initialize
the MshvEmulatorContext and later call the emulator to decode the
instruction.

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

hypervisor/src/mshv/aarch64/emulator.rs

@@ -28,7 +28,7 @@ impl<'a> Emulator<'a> {
         Emulator { context }
     }
 
-    /// Decode the instruction using the syndrome register.
+    /// Decode & emulate the instruction using the syndrome register.
     pub fn emulate_with_syndrome(&mut self) -> Result<bool, PlatformError> {
         let esr_el2 = EsrEl2::from(self.context.syndrome);
         if !matches!(