#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
+#define NO_PROGRESS_CYCLE_LIMIT 4000000ULL // 4 million cycles, about 1ms on a 4 GHz machine
+
+#define YIELD_TIME_USEC 1000
+
//
// This should trigger a #GP if cpl != 0, otherwise, yield to host
//
-int v3_handle_halt(struct guest_info * info) {
-
+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 total_cycles;
+
PrintDebug("CPU Yield\n");
- while (!v3_intr_pending(info)) {
- rdtscll(yield_start);
- v3_yield(info);
-
- v3_update_time(info, yield_start - info->time_state.cached_host_tsc);
-
- rdtscll(info->time_state.cached_host_tsc);
-
+ total_cycles = 0;
+
+ while (!v3_intr_pending(info) && (info->vm_info->run_state == VM_RUNNING)) {
+ uint64_t t, cycles;
+ /* Yield, allowing time to pass while yielded */
+ t = v3_get_host_time(&info->time_state);
+
+ // adaptively select the best yield option
+ if (total_cycles > NO_PROGRESS_CYCLE_LIMIT) {
+ // Slow yield - will take at least YIELD_TIME_USEC to come back
+ v3_yield(info,YIELD_TIME_USEC);
+ } else {
+ // Fast yield - may come back immediately
+ v3_yield(info,-1);
+ }
+
+ cycles = v3_get_host_time(&info->time_state) - t;
+
+ if ((total_cycles + cycles) > total_cycles) {
+ total_cycles += cycles;
+ }
+
+ v3_advance_time(info, &cycles);
+
+ v3_update_timers(info);
+
/* 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");
+ /* asm("hlt"); */
}
+
}
+
+ /* V3_Print("palacios: done with halt\n"); */
info->rip += 1;
}
