The document discusses a workshop on inter-cloud computing held in Kanazawa on May 7, 2013. It includes diagrams showing the architecture of hybrid HaaS/IaaS cloud platforms with virtual machines running at different levels. Performance test results are presented comparing bare metal, IaaS virtual machines, and HaaS virtual machines running Linux or KVM hypervisors. The results show higher overhead for HaaS virtual machines compared to IaaS, with even higher overhead for nested virtualization using KVM at multiple levels.