or evacuate from failing HW •For balancing load Requirements of a VMM on VM as if on native hw •Guest sw should behave exactly not be able to change allocation of RT resources directly •Guest sw should interrupts should be virtualised •Timer processor modes- system and user •Two of instruction available only in system mode •Priveleged subset More issues on VM usage support for virtual machine •ISA support –IBM360 do no support –80x86 of virtual memory •Use of virtual- real- physical memories –Concept of extra indirection use shadow page table –Instead I/Os •Virtualising i/o –More diversity –More disks to partitioned virtual disks –Physical cards time sliced –Network
•For balancing load or evacuate from failing HW Requirements of a VMM •Guest sw should behave exactly on VM as if on native hw •Guest sw should not be able to change allocation of RT resources directly •Timer interrupts should be virtualised •Two processor modes- system and user •Priveleged subset of instruction available only in system mode More issues on VM usage •ISA support for virtual machine –IBM360 support –80x86 do no support •Use of virtual memory –Concept of virtual- real- physical memories –Instead of extra indirection use shadow page table •Virtualising I/Os –More i/o –More diversity –Physical disks to partitioned virtual disks –Network cards time sliced