From: Maciek Swiech <dotpyfe@u.northwestern.edu>
Date: Fri, 6 Dec 2013 19:14:40 +0000 (-0600)
Subject: Fix for floating point save/restore in case where fp context switching is turned off
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=ade1ede94c894363a3d4652d93540aef170b1276;hp=6bc36dbea509d599d3c6fdb42e1a9c67144f5023;p=palacios.git

Fix for floating point save/restore in case where fp context switching is turned off
---

diff --git a/palacios/include/palacios/vmm_fp.h b/palacios/include/palacios/vmm_fp.h
index 76b377d..0271458 100644
--- a/palacios/include/palacios/vmm_fp.h
+++ b/palacios/include/palacios/vmm_fp.h
@@ -163,8 +163,16 @@ int v3_deinit_fp(void);
 
 #ifndef V3_CONFIG_FP_SWITCH
 
-#define V3_FP_EXIT_SAVE(core) 
-#define V3_FP_ENTRY_RESTORE(core)
+/* Ideally these would use the TS trick to do lazy calls to used_fpu() */
+#define V3_FP_EXIT_SAVE(core)
+
+#define V3_FP_ENTRY_RESTORE(core)	 				    \
+  do {							                    \
+    if ((core)->fp_state.need_restore) {				    \
+      v3_put_fp_state(core);                                \
+      (core)->fp_state.need_restore=0;		   			    \
+    }                                                       \
+  } while (0)
 
 #else
 
diff --git a/palacios/src/palacios/vmm_barrier.c b/palacios/src/palacios/vmm_barrier.c
index ba88e2b..a94e40f 100644
--- a/palacios/src/palacios/vmm_barrier.c
+++ b/palacios/src/palacios/vmm_barrier.c
@@ -198,9 +198,12 @@ int v3_wait_at_barrier(struct guest_info * core) {
     if (barrier->active == 0) {
 	return 0;
     }
-
-#ifdef V3_CONFIG_LAZY_FP_SWITCH
+#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);
@@ -219,9 +222,13 @@ int v3_wait_at_barrier(struct guest_info * core) {
         // Barrier wait will spin if there is no competing work
 	v3_yield(core,-1);
     }
-    
-#ifdef V3_LAZY_FP_SWITCH
+
+#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;