+/*
+ * This file is part of the Palacios Virtual Machine Monitor developed
+ * by the V3VEE Project with funding from the United States National
+ * Science Foundation and the Department of Energy.
+ *
+ * The V3VEE Project is a joint project between Northwestern University
+ * and the University of New Mexico. You can find out more at
+ * http://www.v3vee.org
+ *
+ * Copyright (c) 2008, Peter Dinda <pdinda@northwestern.edu>
+ * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
+ * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
+ * All rights reserved.
+ *
+ * Author: Peter Dinda <pdinda@northwestern.edu>
+ *
+ * This is free software. You are permitted to use,
+ * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
+ */
+
#include <palacios/svm_halt.h>
#include <palacios/vmm_intr.h>
-// From GeekOS
-void Yield(void);
+
+
+#ifndef CONFIG_DEBUG_HALT
+#undef PrintDebug
+#define PrintDebug(fmt, args...)
+#endif
+
//
-// 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 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;
- uint32_t gap = 0;
-
- PrintDebug("GeekOS Yield\n");
-
- rdtscll(yield_start);
- Yield();
- rdtscll(yield_stop);
-
-
- //v3_update_time(info, yield_stop - yield_start);
- gap = yield_stop - yield_start;
- v3_raise_irq(info, 0);
+int v3_handle_svm_halt(struct guest_info * info) {
+
+ if (info->cpl != 0) {
+ v3_raise_exception(info, GPF_EXCEPTION);
+ } else {
- PrintDebug("GeekOS Yield Done (%d cycles)\n", gap);
+ 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);
- info->rip+=1;
- }
- return 0;
+ //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);
+ }
+
+
+ PrintDebug("CPU Yield Done (%d cycles)\n", gap);
+
+ info->rip+=1;
+ }
+ return 0;
}
