fix(kvm): remove UnexpectedExit, let catch-all handle unexpected HLT

Remove the dedicated VcpuExit::Hlt match arm and UnexpectedExit error
variant in the hw-interrupts run loop. Unexpected HLT now falls through
to the Ok(other) catch-all, returning VmExit::Unknown which gets
converted to the existing UnexpectedVmExit in hyperlight_vm.

Signed-off-by: danbugs <danilochiarlone@gmail.com>

Author: danbugs

src/hyperlight_host/src/hypervisor/virtual_machine/kvm/x86_64.rs

@@ -206,11 +206,6 @@ impl KvmVm {
     fn run_vcpu_hw_interrupts(&mut self) -> std::result::Result<VmExit, RunVcpuError> {
         loop {
             match self.vcpu_fd.run() {
-                Ok(VcpuExit::Hlt) => {
-                    return Err(RunVcpuError::UnexpectedExit(
-                        "KVM hw-interrupts: unexpected VcpuExit::Hlt".to_string(),
-                    ));
-                }
                 Ok(VcpuExit::IoOut(port, data)) => {
                     if port == VmAction::Halt as u16 {
                         // Stop the timer thread before returning.

src/hyperlight_host/src/hypervisor/virtual_machine/mod.rs

@@ -202,8 +202,6 @@ pub enum RunVcpuError {
     IncrementRip(HypervisorError),
     #[error("Parse GPA access info failed")]
     ParseGpaAccessInfo,
-    #[error("Unexpected vCPU exit: {0}")]
-    UnexpectedExit(String),
     #[error("Unknown error: {0}")]
     Unknown(HypervisorError),
 }