Added barrier locking to the core migration functionality

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

diff --git a/palacios/src/palacios/vmm_halt.c b/palacios/src/palacios/vmm_halt.c
index 2be016c..bfe2e5a 100644 (file)
--- a/palacios/src/palacios/vmm_halt.c
+++ b/palacios/src/palacios/vmm_halt.c
@@ -20,9 +20,9 @@
 
 #include <palacios/vmm_halt.h>
 #include <palacios/vmm_intr.h>
+#include <palacios/vmm_lowlevel.h> 
 
-
-#ifndef CONFIG_DEBUG_HALT
+#ifndef V3_CONFIG_DEBUG_HALT
 #undef PrintDebug
 #define PrintDebug(fmt, args...)
 #endif
@@ -38,36 +38,30 @@ int v3_handle_halt(struct guest_info * info) {
     if (info->cpl != 0) { 
        v3_raise_exception(info, GPF_EXCEPTION);
     } else {
-    
-       uint64_t yield_start = 0;
-       uint64_t yield_stop = 0;
-       uint32_t gap = 0;
-       
        PrintDebug("CPU Yield\n");
-       
-       rdtscll(yield_start);
-       v3_yield(info);
-       rdtscll(yield_stop);
-    
-    
-       //v3_update_time(info, yield_stop - yield_start);
-       gap = yield_stop - yield_start;
 
-       /*  WARNING!!! WARNING!!!
-        *  
-        * DO NOT REMOVE THIS CONDITIONAL!!!
-        *
-        * It is common for an OS to issue an IO op, and then sit in a halt loop
-        * waiting for the device to complete and raise an irq.
-        * If you remove this then the timer interrupt will ALWAYS subvert the completion 
-        * interrupt and stall the guest.
-        */
-       if (!v3_intr_pending(info)) {
-           v3_raise_irq(info, 0);
+       while (!v3_intr_pending(info)) {
+           /* Since we're in an exit, time is already paused here, so no need to pause again. */
+         //        V3_Print("palacios: halt->yield\n");
+
+           v3_yield(info);
+           
+           v3_disable_ints();
+           v3_update_timers(info);
+           v3_enable_ints();
+           
+           /* At this point, we either have some combination of 
+              interrupts, including perhaps a timer interrupt, or 
+              no interrupt.
+           */
+           if (!v3_intr_pending(info)) {
+               /* if no interrupt, then we do halt */
+               /* asm("hlt"); */
+           }
+
        }
 
-       
-       PrintDebug("CPU Yield Done (%d cycles)\n", gap);
+       /* V3_Print("palacios: done with halt\n"); */
        
        info->rip += 1;
     }