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 f887a05..a94e40f 100644 (file)
--- a/palacios/src/palacios/vmm_barrier.c
+++ b/palacios/src/palacios/vmm_barrier.c
@@ -93,6 +93,10 @@ int v3_wait_for_barrier(struct v3_vm_info * vm_info, struct guest_info * local_c
     int all_blocked = 0;
     int i = 0;
 
+    if (barrier->active == 0) {
+       return -1;
+    }
+
     // wait for barrier catch on all cores
     while (all_blocked == 0) {
        all_blocked = 1;
@@ -116,7 +120,8 @@ int v3_wait_for_barrier(struct v3_vm_info * vm_info, struct guest_info * local_c
            break;
        }
 
-       v3_yield(local_core);
+        // return immediately and spin if there is no one to yield to 
+       v3_yield(local_core,-1);
     }
 
     return 0;
@@ -137,6 +142,12 @@ int v3_wait_for_barrier(struct v3_vm_info * vm_info, struct guest_info * local_c
 int v3_raise_barrier(struct v3_vm_info * vm_info, struct guest_info * local_core) {
     int ret = 0;
 
+
+    if ((vm_info->run_state != VM_RUNNING) && 
+       (vm_info->run_state != VM_SIMULATING)) {
+       return 0;
+    }
+
     ret = v3_raise_barrier_nowait(vm_info, local_core);
 
     if (ret != 0) {
@@ -158,6 +169,12 @@ int v3_raise_barrier(struct v3_vm_info * vm_info, struct guest_info * local_core
 int v3_lower_barrier(struct v3_vm_info * vm_info) {
     struct v3_barrier * barrier = &(vm_info->barrier);
 
+    
+    if ((vm_info->run_state != VM_RUNNING) && 
+       (vm_info->run_state != VM_SIMULATING)) {
+       return 0;
+    }
+
     // Clear the active flag, so cores won't wait 
     barrier->active = 0;
 
@@ -181,8 +198,15 @@ 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 %d waiting at barrier\n", core->vcpu_id);
+    V3_Print(core->vm_info, core, "Core %d waiting at barrier\n", core->vcpu_id);
 
     /*  Barrier has been activated. 
      *  Wait here until it's lowered
@@ -191,12 +215,21 @@ int v3_wait_at_barrier(struct guest_info * core) {
     
     // set cpu bit in barrier bitmap
     v3_bitmap_set(&(barrier->cpu_map), core->vcpu_id);
-    V3_Print("Core %d bit set as waiting\n", core->vcpu_id);
+    V3_Print(core->vm_info, core, "Core %d bit set as waiting\n", core->vcpu_id);
 
     // wait for cpu bit to clear
     while (v3_bitmap_check(&(barrier->cpu_map), core->vcpu_id)) {
-       v3_yield(core);
+        // 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;
 }