How does VMs work - • The VM device drivers will communicate with the VM device emulation software • A special file in the hard drive may show

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How does VMs work? They use “Trap” and “Emulate” A processor can be virtualized if all instructions that access a privileged state cause a trap or interrupt. Trap == interrupt The VM will catch the trap and emulate what the OS in that VM tries to do.
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Memory Virtualization Traditionally a VM address is translated to a Physical memory address using the MMU and te guest’s Page table. In a VM, the VM layer will use a “shadow page table” instead of the guest’s page table. The VM layer will create this shadow page table that is used instead of the guest’s page table. The “shadow page table” is built from the guests page table and the VM layer.
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VM Memory Virtualization Virtual Memory Shado w Page Table Guest’s Page Table Physical Memory
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I/O Virtualization The VM supplies its own device drivers.
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Unformatted text preview: • The VM device drivers will communicate with the VM device emulation software. • A special file in the hard drive may show to a OS as a whole hard drive. • The Ethernet interface will be shared across multiple OS guests with same or different IP addresses. I/O Virtualization Guest OS 1 Device Driver Device Emulation I/O Stack Device Driver Guest OS 2 Device Driver Virtualization Layer VM Products • Oracle Virtual Box – Open Source – Free – Works fine – See https://www.virtualbox.org/ • VMware – Solid and fast – Commercially available. – VMware player is free with some restrictions. – See http://www.vmware.com/ – For Purdue CS students you can get it at: References • http://labs.vmware.com/academic/videos/i ntroduction-virtual-machines...
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This note was uploaded on 01/30/2012 for the course CS 354 taught by Professor Staff during the Fall '08 term at Purdue University-West Lafayette.

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How does VMs work - • The VM device drivers will communicate with the VM device emulation software • A special file in the hard drive may show

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