Cleaned up time management stuff, being more careful on signs of various time computa...

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

diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c
index 27bb2fc..2295b3f 100644 (file)
--- a/palacios/src/palacios/vmm_time.c
+++ b/palacios/src/palacios/vmm_time.c
@@ -99,7 +99,7 @@ int v3_start_time(struct guest_info * info) {
 int v3_offset_time( struct guest_info * info, sint64_t offset )
 {
     struct vm_time * time_state = &(info->time_state);
-//    PrintDebug("Adding additional offset of %lld to guest time.\n", offset);
+    PrintDebug("Adding additional offset of %lld to guest time.\n", offset);
     time_state->guest_host_offset += offset;
     return 0;
 }
@@ -152,7 +152,7 @@ static int yield_host_time(struct guest_info * info) {
 
     /* We do *not* assume the guest timer was paused in the VM. If it was
      * this offseting is 0. If it wasn't, we need this. */
-    v3_offset_time(info, (sint64_t)old_guest_time - (sint64_t)guest_time);
+    v3_offset_time(info, (sint64_t)(old_guest_time - guest_time));
 
     return 0;
 }
@@ -175,12 +175,12 @@ static int skew_guest_time(struct guest_info * info) {
        if (time_state->enter_time) {
            /* Limit forward skew to 10% of the amount the guest has
             * run since we last could skew time */
-           max_skew = ((sint64_t)guest_time - (sint64_t)time_state->enter_time) / 10;
+           max_skew = (sint64_t)(guest_time - time_state->enter_time) / 10.0;
        } else {
            max_skew = 0;
        }
 
-       desired_skew = (sint64_t)target_guest_time - (sint64_t)guest_time;
+       desired_skew = (sint64_t)(target_guest_time - guest_time);
        skew = desired_skew > max_skew ? max_skew : desired_skew;
        PrintDebug("Guest %lld cycles behind where it should be.\n",
                   desired_skew);
@@ -226,13 +226,21 @@ int
 v3_time_enter_vm( struct guest_info * info )
 {
     struct vm_time * time_state = &(info->time_state);
-    uint64_t guest_time, host_time;
+    uint64_t host_time;
 
     host_time = v3_get_host_time(time_state);
-    guest_time = v3_get_guest_time(time_state);
     time_state->enter_time = host_time;
 #ifdef V3_CONFIG_TIME_DILATION
-    time_state->guest_host_offset = (sint64_t)guest_time - (sint64_t)host_time;
+    { 
+        uint64_t guest_time;
+       sint64_t offset;
+        guest_time = v3_compute_guest_time(time_state, host_time);
+       // XXX we probably want to use an inline function to do these
+        // time differences to deal with sign and overflow carefully
+       offset = (sint64_t)guest_time - (sint64_t)host_time;
+       PrintDebug("v3_time_enter_vm: guest time offset %lld from host time.\n", offset);
+        time_state->guest_host_offset = offset;
+    }
 #else
     time_state->guest_host_offset = 0;
 #endif
@@ -269,11 +277,11 @@ int v3_remove_timer(struct guest_info * info, struct v3_timer * timer) {
 void v3_update_timers(struct guest_info * info) {
     struct vm_time *time_state = &info->time_state;
     struct v3_timer * tmp_timer;
-    uint64_t old_time = info->time_state.last_update;
     sint64_t cycles;
+    uint64_t old_time = info->time_state.last_update;
 
     time_state->last_update = v3_get_guest_time(time_state);
-    cycles = time_state->last_update - old_time;
+    cycles = (sint64_t)(time_state->last_update - old_time);
     V3_ASSERT(cycles >= 0);
 
     //    V3_Print("Updating timers with %lld elapsed cycles.\n", cycles);