krata: log when a guest start failures occurs

crates/daemon/src/reconcile/guest.rs

@@ -134,6 +134,7 @@ impl GuestReconciler {
                 guest.state.as_mut().unwrap().error_info = Some(GuestErrorInfo {
                     message: error.to_string(),
                 });
+                warn!("failed to start guest {}: {}", guest.id, error);
                 true
             }
         };

crates/xen/xencall/src/lib.rs

@@ -87,6 +87,13 @@ impl XenCall {
             if ptr == MAP_FAILED {
                 None
             } else {
+                trace!(
+                    "call fd={} mmap addr={:#x} len={} = {:#x}",
+                    self.handle.as_raw_fd(),
+                    addr,
+                    len,
+                    ptr as u64,
+                );
                 Some(ptr as u64)
             }
         }