Qemu-KVM preparation knowledge

Qemu-KVM is currently a popular virtualization technology. I will present a series of qemu-KVM content here in the next period. The virtualization mentioned here refers to the virtualization technology based on CPU hardware support.

KVM (kernel-based Virtual Machine) Website: http://www.linux-kvm.org/page/Main_Page

Introduction:

KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux on x86 hardware containing virtualization extensions (Intel VT or AMD-V ). it consists of a loadable kernel module, KVM. ko, that provides the core virtualization alization infrastructure
And a processor specific module, kvm-intel.ko or kvm-amd.ko. KVM also requires a modified qemu although work is underway to get the required changes upstream.

Using KVM, one can run multiple virtual machines running unmodified Linux or Windows images. Each virtual machine has private virtualized alized hardware: a network card, disk, graphics adapter, etc.

The kernel component of KVM is supported in mainline Linux, as of 2.6.20.

KVM is open source software.

Qemu Official Website: http://wiki.qemu.org/Main_Page

Introduction:

Qemu is a generic and open source machine emulator and virtualizer.

When used as a machine emulator, qemu can run OSes and programs made for one machine (e.g. an arm board) on a different machine (e.g. your own PC ). by using dynamic translation, it achieves very good performance.

When used as a virtualizer, qemu achieves near native performances by executing the guest code directly on the host CPU. qemu supports virtualization when executing under the xen hypervisor or using the KVM kernel module in Linux. when using KVM, qemu can Virtualize
X86, server and Embedded PowerPC, and s390 guests.

To be precise, KVM is a module of Linux kernel. You can use the modprobe command to load the KVM module. After the module is loaded, you can use other tools to create virtual machines. However, only the KVM module is far from enough, because users cannot directly control the kernel module to do things, and you must have a tool running in the user space. For this user space tool, KVM developers chose the open-source virtualization software qemu. Qemu is also a virtualization software. It features different virtual CPUs. For example, you can use an x86 CPU to virtualize a power CPU and compile a program that can run on power. KVM uses a part of qemu and is transformed to a user space tool that can control KVM. So you will see that the official KVM download has two major parts (qemu and KVM) three files (KVM module, qemu tool and a collection of the two ). In other words, you can upgrade only the KVM module or the qemu tool. This is KVM and qemu.
.

Linux Kernel-based Virtual Machine (KVM) is a Linux open source virtualization software, based on hardware virtualization extensions (Intel VT-X and AMD-V) and qemu modified version. KVM
Another two modules are: KVM. Ko is the infrastructure that provides core virtualization; processor-specific module kvm-intel.ko and kvm-amd.ko. It is designed to support complete hardware simulation when multiple unaltered PC operating systems need to be guided.

Appendix: Debian KVM instance Creation