Add part20
Merge branch 'master' of github.com:syuu1228/howto_implement_hypervisor
Merge pull request #8 from hiroyuki-sato/patch-for-syuu1228

Part3の修正
Add interrupt_routing
Add table on part4.tex
Merge branch 'master' of github.com:syuu1228/howto_implement_hypervisor
Merge branch 'master' of github.com:syuu1228/howto_implement_hypervisor