In KVM Virtualization, guests are represented by processes on the host machine. This means that processing power, memory, and other resources of the host are used to emulate the functions and capabilities of the guest's virtual hardware.

However, guest hardware can be less effective at using the resources than the host. Therefore, adjusting the amount of allocated host resources may be needed for the guest to perform its tasks at the expected speed. In addition, various types of virtual hardware may have different levels of overhead, so an appropriate virtual hardware configuration can have significant impact on guest performance. Finally, depending on the circumstances, specific configurations enable virtual machines to use host resources more efficiently.