2 * This file is part of the Palacios Virtual Machine Monitor developed
3 * by the V3VEE Project with funding from the United States National
4 * Science Foundation and the Department of Energy.
6 * The V3VEE Project is a joint project between Northwestern University
7 * and the University of New Mexico. You can find out more at
10 * Copyright (c) 2008, Peter Dinda <pdinda@northwestern.edu>
11 * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
12 * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org>
13 * All rights reserved.
15 * Author: Peter Dinda <pdinda@northwestern.edu>
17 * This is free software. You are permitted to use,
18 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
21 #include <palacios/vmm_halt.h>
22 #include <palacios/vmm_intr.h>
23 #include <palacios/vmm_lowlevel.h>
25 #ifndef V3_CONFIG_DEBUG_HALT
27 #define PrintDebug(fmt, args...)
31 #define NO_PROGRESS_CYCLE_LIMIT 4000000ULL // 4 million cycles, about 1ms on a 4 GHz machine
33 #define YIELD_TIME_USEC 1000
37 // This should trigger a #GP if cpl != 0, otherwise, yield to host
40 int v3_handle_halt(struct guest_info * info)
44 v3_raise_exception(info, GPF_EXCEPTION);
46 uint64_t total_cycles;
49 PrintDebug("CPU Yield\n");
53 while (!v3_intr_pending(info) && (info->vm_info->run_state == VM_RUNNING)) {
55 /* Yield, allowing time to pass while yielded */
56 t = v3_get_host_time(&info->time_state);
58 // adaptively select the best yield option
59 if (total_cycles > NO_PROGRESS_CYCLE_LIMIT) {
60 // Slow yield - will take at least YIELD_TIME_USEC to come back
61 v3_yield(info,YIELD_TIME_USEC);
63 // Fast yield - may come back immediately
67 cycles = v3_get_host_time(&info->time_state) - t;
69 if ((total_cycles + cycles) > total_cycles) {
70 total_cycles += cycles;
73 v3_advance_time(info, &cycles);
75 v3_update_timers(info);
77 /* At this point, we either have some combination of
78 interrupts, including perhaps a timer interrupt, or
81 if (!v3_intr_pending(info)) {
82 /* if no interrupt, then we do halt */
88 /* V3_Print("palacios: done with halt\n"); */