X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fsvm_halt.c;h=2e6f9e2eaf8363971e5eb8d18884c6cc1da5c238;hb=afffedf9ab57494864f0710a2530958fa9e216cc;hp=54e8a3d3e68740a680f61d7cca0926fae4ccb3d0;hpb=266af4b5b19da7bee8e7445288c7c1cb3ee194c7;p=palacios.git

diff --git a/palacios/src/palacios/svm_halt.c b/palacios/src/palacios/svm_halt.c
index 54e8a3d..2e6f9e2 100644
--- a/palacios/src/palacios/svm_halt.c
+++ b/palacios/src/palacios/svm_halt.c
@@ -18,11 +18,6 @@
  * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
  */
 
-
-
-
-
-
 #include <palacios/svm_halt.h>
 #include <palacios/vmm_intr.h>
 
@@ -35,39 +30,47 @@
 
 
 //
-// This should trigger a #GP if cpl!=0, otherwise, yield to host
+// This should trigger a #GP if cpl != 0, otherwise, yield to host
 //
 
-int v3_handle_svm_halt(struct guest_info * info)
-{
-    if (info->cpl!=0) { 
+int v3_handle_svm_halt(struct guest_info * info) {
+
+    if (info->cpl != 0) { 
 	v3_raise_exception(info, GPF_EXCEPTION);
     } else {
     
-	// What we should do is starting waiting on an OS event that will
-	// result in an injection of an interrupt.
-	
-	// What we will hackishly do instead is resume on any event
-	// Plus is this totally GeekOS specific
-	
-	ullong_t yield_start = 0;
-	ullong_t yield_stop = 0;
+	uint64_t yield_start = 0;
+	uint64_t yield_stop = 0;
 	uint32_t gap = 0;
 	
-	PrintDebug("GeekOS Yield\n");
+	PrintDebug("CPU Yield\n");
 	
 	rdtscll(yield_start);
-	V3_Yield();
+	v3_yield(info);
 	rdtscll(yield_stop);
     
     
 	//v3_update_time(info, yield_stop - yield_start);
 	gap = yield_stop - yield_start;
-	v3_raise_irq(info, 0);
+
+	/*  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);
+	}
+
 	
-	PrintDebug("GeekOS Yield Done (%d cycles)\n", gap);
+	PrintDebug("CPU Yield Done (%d cycles)\n", gap);
 	
 	info->rip+=1;
     }
+
     return 0;
 }