int v3_move_vm_core(struct v3_vm_info * vm, int vcore_id, int target_cpu) {
struct guest_info * core = NULL;
- if(vcore_id < 0 || vcore_id > vm->num_cores) {
+ if ((vcore_id < 0) || (vcore_id >= vm->num_cores)) {
+ PrintError("Attempted to migrate invalid virtual core (%d)\n", vcore_id);
return -1;
}
core = &(vm->cores[vcore_id]);
- if(target_cpu != core->pcpu_id &&
- core->core_move_state != CORE_MOVE_PENDING){
- core->core_move_state = CORE_MOVE_PENDING;
- core->target_pcpu_id = target_cpu;
- v3_interrupt_cpu(vm, core->pcpu_id, 0);
+ if (target_cpu == core->pcpu_id) {
+ PrintError("Attempted to migrate to local core (%d)\n", target_cpu);
+ // well that was pointless
+ return 0;
+ }
- while(core->core_move_state != CORE_MOVE_DONE){
- v3_yield(NULL);
- }
+ if (core->core_thread == NULL) {
+ PrintError("Attempted to migrate a core without a valid thread context\n");
+ return -1;
}
+ while (v3_raise_barrier(vm, NULL) == -1);
+
+ V3_Print("Performing Migration from %d to %d\n", core->pcpu_id, target_cpu);
+
+ // Double check that we weren't preemptively migrated
+ if (target_cpu != core->pcpu_id) {
+
+ V3_Print("Moving Core\n");
+
+ if (V3_MOVE_THREAD_TO_CPU(target_cpu, core->core_thread) != 0) {
+ PrintError("Failed to move Vcore %d to CPU %d\n",
+ core->vcpu_id, target_cpu);
+ v3_lower_barrier(vm);
+ return -1;
+ }
+ /* There will be a benign race window here:
+ core->pcpu_id will be set to the target core before its fully "migrated"
+ However the core will NEVER run on the old core again, its just in flight to the new core
+ */
+ core->pcpu_id = target_cpu;
+
+ V3_Print("core now at %d\n", core->pcpu_id);
+
+ }
+
+
+
+
+ v3_lower_barrier(vm);
+
return 0;
}
