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4.3.4. CPU models

CPU models define which host CPU features are available to the guest operating system. qemu-kvm and libvirt contain definitions for a number of current processor models, allowing users to enable features that are available only in newer CPU models. The CPU feature set available to guests depends on support in the host CPU kernel. The qemu-kvm code must also allow the feature to be enabled.
To safely migrate virtual machines between hosts with different CPU feature sets, qemu-kvm does not expose all CPU features from the host CPU to guest operating systems by default. Instead, CPU features are exposed to virtual machines based on the chosen CPU model.
It is also possible to enable or disable specific CPU features in a virtual machine's XML configuration. However, it is safer to use predefined CPU models, as incorrect configuration can cause compatibility issues with the guest operating system.


For more information on CPU model availability and configuration, refer to the Fedora Virtualization Deployment and Administration Guide.