In this paper we consider the security and trust implications of virtual machine (VM) migration from one cloud platform to the other in an Infrastructure-as-a-Service (IaaS) cloud service model. We show how to extend and complement previous Trusted Computing techniques for secure VM launch to also cover the VM migration case. In particular, we propose a Trust_Token based VM migration protocol which guarantees that the user VM can only be migrated to a trustworthy cloud platform. Different from previous schemes, our solution is not dependent on an active (on-line) trusted third party. We show how our proposed mechanisms fulfill major security and trust requirements for secure VM migration in cloud environments.