Raise GP fault in VTL0 if VTL1 panics

litebox_platform_lvbs/src/mshv/mod.rs

@@ -10,7 +10,7 @@ mod hvcall_vp;
 mod mem_integrity;
 pub(crate) mod ringbuffer;
 pub(crate) mod vsm;
-mod vsm_intercept;
+pub mod vsm_intercept;
 mod vsm_optee_smc;
 pub mod vtl1_mem_layout;
 pub mod vtl_switch;

litebox_platform_lvbs/src/mshv/vsm_intercept.rs

@@ -48,6 +48,12 @@ pub enum InterceptedRegisterName {
     Unknown = 0xffff_ffff,
 }
 
+/// # Panics
+///
+/// Panics if:
+/// - Failed to get intercept message type
+/// - Failed to raise VTL0 GP fault
+/// - Intercepted write to unknown MSR/register
 pub fn vsm_handle_intercept() {
     let simp_page = with_per_cpu_variables_mut(|per_cpu_variables| unsafe {
         &mut *per_cpu_variables.hv_simp_page_as_mut_ptr()
@@ -147,7 +153,7 @@ fn advance_vtl0_rip(int_msg_hdr: &HvInterceptMessageHeader) -> Result<u64, Hyper
 }
 
 #[inline]
-fn raise_vtl0_gp_fault() -> Result<u64, HypervCallError> {
+pub fn raise_vtl0_gp_fault() -> Result<u64, HypervCallError> {
     let mut exception = HvPendingExceptionEvent::new();
     exception.set_event_pending(true);
     exception.set_event_type(0_u8);

litebox_platform_lvbs/src/mshv/vtl_switch.rs

@@ -308,6 +308,10 @@ unsafe extern "C" fn vtl_switch_loop_body() {
     }
 }
 
+unsafe extern "C" {
+    pub fn panic_vtl_switch() -> !;
+}
+
 fn vtlcall_dispatch(params: &[u64; NUM_VTLCALL_PARAMS]) -> i64 {
     let func_id = VsmFunction::try_from(u32::try_from(params[0]).unwrap_or(u32::MAX))
         .unwrap_or(VsmFunction::Unknown);

litebox_runner_lvbs/src/lib.rs

@@ -5,13 +5,14 @@
 
 use core::panic::PanicInfo;
 use litebox_platform_lvbs::{
-    arch::{gdt, get_core_id, instrs::hlt_loop, interrupts},
+    arch::{gdt, get_core_id, interrupts},
     debug_serial_println,
     host::{bootparam::get_vtl1_memory_info, per_cpu_variables::allocate_per_cpu_variables},
     mm::MemoryProvider,
     mshv::{
         hvcall,
-        vtl_switch::vtl_switch_loop_entry,
+        vsm_intercept::raise_vtl0_gp_fault,
+        vtl_switch::{panic_vtl_switch, vtl_switch_loop_entry},
         vtl1_mem_layout::{
             PAGE_SIZE, VTL1_INIT_HEAP_SIZE, VTL1_INIT_HEAP_START_PAGE, VTL1_PML4E_PAGE,
             VTL1_PRE_POPULATED_MEMORY_SIZE, get_heap_start_address,
@@ -105,5 +106,6 @@ pub fn run(platform: Option<&'static Platform>) -> ! {
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     serial_println!("{}", info);
-    hlt_loop()
+    let _ = raise_vtl0_gp_fault();
+    unsafe { panic_vtl_switch() }
 }