KVM practical principles advance and performance tuning Reading Notes-Virtualization Foundation

VMM: virtual Monitor, also known as Hypervisor, is a software layer introduced to achieve virtualization. It downwards controls the actual physical resources. Resources that are presented upward to the virtual machine N copies of logic. In order to do this, it is necessary to "steal" the virtual machine's access to physical resources-intercept and redirect it, making the virtual machine think that it is enjoying the physical resources exclusively.

The actual physical environment in which the virtual machine monitor runs becomes the host, and the virtual logical host on it is called the client. Copy that.

There are two goals for the ideal virtualization to achieve:

1. Let clients have no idea that they are running in a virtualized environment and think they are running in a native environment.

two。 There is no need for VMM to intervene in the client's running process at all.

Paravirtualization:

The so-called paravirtualization, also known as (quasi-virtualization), is to let the client realize that it is running in a virtualized environment and do the corresponding processing to match the VMM.

Paravirtualization requires modification of the client's operating system (kernel modification) to achieve proactive notification. A typical paravirtualization technology is virtio, where virtio requires drivers to be installed in both the host / VMM and the client accordingly.