Basic HVM data structures and functions

[palacios.git] / palacios / src / palacios / vmm_barrier.c

diff --git a/palacios/src/palacios/vmm_barrier.c b/palacios/src/palacios/vmm_barrier.c
index 35efe0f..a94e40f 100644 (file)
--- a/palacios/src/palacios/vmm_barrier.c
+++ b/palacios/src/palacios/vmm_barrier.c
@@ -120,6 +120,7 @@ int v3_wait_for_barrier(struct v3_vm_info * vm_info, struct guest_info * local_c
            break;
        }
 
+        // return immediately and spin if there is no one to yield to 
        v3_yield(local_core,-1);
     }
 
@@ -197,6 +198,13 @@ int v3_wait_at_barrier(struct guest_info * core) {
     if (barrier->active == 0) {
        return 0;
     }
+#ifndef V3_CONFIG_FP_SWITCH
+    v3_get_fp_state(core); // snapshot FP state now
+#else
+#   ifdef V3_CONFIG_LAZY_FP_SWITCH
+    v3_get_fp_state(core); // snapshot FP state now regardless of lazy eval
+#   endif
+#endif
 
     V3_Print(core->vm_info, core, "Core %d waiting at barrier\n", core->vcpu_id);
 
@@ -211,8 +219,17 @@ int v3_wait_at_barrier(struct guest_info * core) {
 
     // wait for cpu bit to clear
     while (v3_bitmap_check(&(barrier->cpu_map), core->vcpu_id)) {
+        // Barrier wait will spin if there is no competing work
        v3_yield(core,-1);
     }
 
+#ifndef V3_CONFIG_FP_SWITCH    
+    core->fp_state.need_restore=1;  // restore FP on next entry
+#else
+#   ifdef V3_CONFIG_LAZY_FP_SWITCH
+    core->fp_state.need_restore=1;  // restore FP on next entry
+#   endif
+#endif
+
     return 0;
 }