Chapter 3. KVM Support Status


3.1. Supported Features and Tools
3.2. Unsupported Features and Tools

The following list contains features and tools as supported by Novell—this does not necessarily reflect the support status of the software itself. For a list of qemu-kvm command switches supported by Novell, refer to Section A.3, “QEMU Command Line Options”.

3.1. Supported Features and Tools


Define and install VM Guests via vm-install including specifying RAM, disk type and location, video type, keyboard mapping, NIC type, binding, MAC address, and boot method.

Restrictions: Currently only the raw disk format is supported. NIC creation is restricted to using Realtek or Virtio NICs.

Virtual Machine Manager

Manage guests via Virtual Machine Manager using the following functions: autostart, start, stop, restart, pause, unpause, save, restore, clone, migrate, special key sequence insertion, guest console viewers, performance monitoring, and CPU pinning. Furthermore, static modifications of CPU, RAM, boot method, disk, NIC, mouse, display, video and host PCI assignments are supported.

Restrictions: The following features are currently not supported: sound devices, vmvga (vmware), Xen video, and adding physical USB devices.


Manage guests via the command line.

Restrictions: Requires XML descriptions as created by vm-install or virt-manager. Altering these descriptions via virsh edit is not supported. The supported virsh functionality is restricted to life cycle functions.


Manage guests via the command line. Although managing via Virtual Machine Manager should be the preferred option, qemu-kvm may be used for greater flexibility. See Section A.3.1, “Supported qemu-kvm Command Line Options” for a list of supported options.

Restrictions: See Section A.3.2, “Unsupported qemu-kvm Command Line Options” for a list of not supported options.


Debugging and monitoring tool.

Restrictions: none.

Kernel Samepage Merging (KSM)

When enabled on the VM Host Server Kernel, KSM allows for automatic sharing of identical memory pages between guests to save host memory.

Restrictions: none.

PCI Passthrough

PCI Passthrough improves performance of PCI devices. It requires a AMD CPU with IOMMU (I/O Memory Mapping Unit) or an Intel CPU with VT-d (Virtualization Technology for Directed I/O). VT-d requires the Kernel parameter "intel_iommu=on". Many PCIe cards from major vendors should be supportable. Refer to system level certifications for specific details, or contact the vendor for support statements.

Non-Uniform Memory Access (NUMA)

NUMA machines are supported. Using numactl to pin qemu-kvm processes to specific nodes is recommended.

3.2. Unsupported Features and Tools

CPU hotplugging

Dynamically changing the number of virtual CPUs assigned to the guest is currently not supported.

Device hotplugging

Dynamically adding or removing devices in the guest is currently not supported.

KVM Kernel Module Parameters

Specifying parameters for the KVM Kernel modules is currently not supported unless done under the direction of Novell support personnel.

Using QEMU without KVM

qemu-kvm can be invoked with the -no-kvm parameter. In this case guest CPU instructions are emulated instead of being executed directly by the processor. This mode is not supported, but may be useful for problem resolution.