func Loop(
vm *platform.Vm,
vcpu *platform.Vcpu,
model *machine.Model,
tracer *loader.Tracer) error {
// It's not really kosher to switch threads constantly when running a
// KVM VCPU. So we simply lock this goroutine to a single system
// thread. That way we know it won't be bouncing around.
runtime.LockOSThread()
defer runtime.UnlockOSThread()
log.Printf("Vcpu[%d] running.", vcpu.Id)
for {
// Enter the guest.
err := vcpu.Run()
// Trace if requested.
trace_err := tracer.Trace(vcpu, vcpu.IsStepping())
if trace_err != nil {
return trace_err
}
// No reason for exit?
if err == nil {
return ExitWithoutReason
}
// Handle the error.
switch err.(type) {
case *platform.ExitPio:
err = model.HandlePio(vm, err.(*platform.ExitPio))
case *platform.ExitMmio:
err = model.HandleMmio(vm, err.(*platform.ExitMmio))
case *platform.ExitDebug:
err = nil
case *platform.ExitShutdown:
// Vcpu shutdown.
return nil
}
// Error handling the exit.
if err != nil {
return err
}
}
// Unreachable.
return nil
}
