Difference between revisions of "stoney cloud: Nested virtualization"
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* https://docs.google.com/file/d/0BzyAwvVlQckedmpobUY1Sm0zNWc/edit | * https://docs.google.com/file/d/0BzyAwvVlQckedmpobUY1Sm0zNWc/edit | ||
| − | For Intel CPUs we are going to enable [ | + | For Intel CPUs we are going to enable [http://www.spinics.net/lists/kvm/msg87634.html Shadow VMCS] which requires a sufficiently new CPU, otherwise it gets ignored. |
| − | http://www.spinics.net/lists/kvm/msg87634.html Shadow VMCS] which requires a sufficiently new CPU, otherwise it gets ignored. | + | |
== Setup == | == Setup == | ||
Revision as of 14:02, 20 December 2013
Abstract
This document describes how to set up nested virtualization on a default installation (until it gets enabled by default).
Nested virtualization permits to start another hypervisor (in our case KVM) inside a virtual machine.
With the current version of Qemu/KVM you can expect a performance of about 25% of the host performance (concerning CPU and Memory access) in a guest within a guest (L2). In the future Qemu/KVM should support Intels Virtual EPT which should give 80% of the host performance for L2.
See:
- http://events.linuxfoundation.org/sites/events/files/cojp13_nakajima.pdf
- https://docs.google.com/file/d/0BzyAwvVlQckedmpobUY1Sm0zNWc/edit
For Intel CPUs we are going to enable Shadow VMCS which requires a sufficiently new CPU, otherwise it gets ignored.
Setup
Login as root, then execute the following and reboot (or rmmod/modprobe the corresponding modules if no VM is running)
cat > /etc/modprobe.d/nested-virtualization.conf << EOF options kvm-intel nested=1 options kvm-amd nested=1 EOF
