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Chapter 50. Virtualization

USB 3.0 support for KVM guests

USB 3.0 host adapter (xHCI) emulation for KVM guests remains a Technology Preview in Red Hat Enterprise Linux 7.4. (BZ#1103193)

Select Intel network adapters now support SR-IOV as a guest on Hyper-V

In this update for Red Hat Enterprise Linux guest virtual machines running on Hyper-V, a new PCI passthrough driver adds the ability to use the single-root I/O virtualization (SR-IOV) feature for Intel network adapters supported by the ixgbevf driver. This ability is enabled when the following conditions are met:
  • SR-IOV support is enabled for the network interface controller (NIC)
  • SR-IOV support is enabled for the virtual NIC
  • SR-IOV support is enabled for the virtual switch
The virtual function (VF) from the NIC is attached to the virtual machine.
The feature is currently supported with Microsoft Windows Server 2016. (BZ#1348508)

No-IOMMU mode for VFIO drivers

As a Technology Preview, this update adds No-IOMMU mode for virtual function I/O (VFIO) drivers. The No-IOMMU mode provides the user with full user-space I/O (UIO) access to a direct memory access (DMA)-capable device without a I/O memory management unit (IOMMU). Note that in addition to not being supported, using this mode is not secure due to the lack of I/O management provided by IOMMU. (BZ#1299662)

The ibmvnic Device Driver has been added

The ibmvnic Device Driver was introduced as a Technology Preview in Red Hat Enterprise Linux 7.3 for IBM POWER architectures. vNIC (Virtual Network Interface Controller) is a new PowerVM virtual networking technology that delivers enterprise capabilities and simplifies network management. It is a high-performance, efficient technology that when combined with SR-IOV NIC provides bandwidth control Quality of Service (QoS) capabilities at the virtual NIC level. vNIC significantly reduces virtualization overhead, resulting in lower latencies and fewer server resources, including CPU and memory, required for network virtualization. (BZ#947163)

virt-v2v can now use vmx configuration files to convert VMware guests

As a Technology Preview, the virt-v2v utility now includes the vmx input mode, which enables the user to convert a guest virtual machine from a VMware vmx configuration file. Note that to do this, you also need access to the corresponding VMware storage, for example by mounting the storage using NFS. (BZ#1441197)

virt-v2v can convert Debian and Ubuntu guests

As a technology preview, the virt-v2v utility can now convert Debian and Ubuntu guest virtual machines. Note that the following problems currently occur when performing this conversion:
  • virt-v2v cannot change the default kernel in the GRUB2 configuration, and the kernel configured in the guest is not changed during the conversion, even if a more optimal version of the kernel is available on the guest.
  • After converting a Debian or Ubuntu VMware guest to KVM, the name of the guest's network interface may change, and thus requires manual configuration. (BZ#1387213)

Virtio devices can now use vIOMMU

As a Technology Preview, this update enables virtio devices to use virtual Input/Output Memory Management Unit (vIOMMU). This guarantees the security of Direct Memory Access (DMA) by allowing the device to DMA only to permitted addresses. However, note that only guest virtual machines using Red Hat Enterprise Linux 7.4 or later are able to use this feature. (BZ#1283251, BZ#1464891)

Open Virtual Machine Firmware

The Open Virtual Machine Firmware (OVMF) is available as a Technology Preview in Red Hat Enterprise Linux 7. OVMF is a UEFI secure boot environment for AMD64 and Intel 64 guests. However, OVMF is not bootable with virtualization components available in RHEL 7. Note that OVMF is fully supported in RHEL 8. (BZ#653382)