Hypervisorläget

Hypervisorläget, often referred to as the hypervisor mode or kernel mode for virtual machines, is a privileged operational state within a computer system. It is a fundamental component of hardware-assisted virtualization, enabling a hypervisor to manage and control multiple guest operating systems or virtual machines on a single physical machine. In this mode, the hypervisor has direct access to the hardware resources such as the CPU, memory, and I/O devices. This level of access is crucial for the hypervisor to intercept and emulate instructions from guest operating systems that would otherwise require privileged access, thereby ensuring isolation and security between virtual machines.

When a virtual machine is running, its operating system typically operates in a less privileged mode. However, certain instructions or operations performed by the guest OS that require direct hardware interaction are trapped by the hypervisor. The hypervisor, running in its privileged hypervisorläget, then handles these trapped operations. This mechanism allows the guest OS to believe it has direct control over the hardware, while in reality, the hypervisor mediates all hardware access. This separation and control are essential for the stability and security of virtualized environments, preventing one virtual machine from interfering with others or with the host system itself. Modern CPUs incorporate specific extensions to support hypervisorläget, making virtualization more efficient and performant.