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This version adds a re-architected XL toolstack that is functionally nearly equivalent to XM/XEND, a prototype credit2 scheduler designed for latency-sensitive workloads and very large systems, CPU Pools for advanced partitioning, support for large systems (>255 processors and 1GB/2MB super page support), support for x86 Advanced Vector eXtension (AVX), and a new Memory Access API enabling integration of third party security solutions into Xen virtualized environments.

A number of important new features and updates were made. These include blktap2, a high performance VHD implementation supporting snapshots and clones including live snapshots. Netchannel2 provides support for new Smart NICs with multi-queue and SR-IOV functionality. Fault tolerance allows live transactional synchronization of VM state between physical servers. Libxenlight is a new library providing higher-level control of Xen between various toolstacks. PV-USB and VGA pass-through were implemented. Furthermore, other features were added, performance and scalability were improved, and many bugs were fixed.

Device passthrough improvements, with particular emphasis on support for client devices. RAS features: CPU and memory offlining. Power management: improved frequency/voltage controls and deep-sleep
support. Scheduler and timers are optimized for peak power savings. Support for the Viridian (Hyper-V) enlightenment interface. Many other x86 and ia64 enhancements and fixes.

This release adds power management (P & C states) in the hypervisor, PVSCSI drivers, and HVM emulation domains. It has improved paravirtualization, device passthrough, hardware-assisted paging, HVM framebuffer, and shadow pagetable performance. It has improved safety of domain transfer across systems with different CPU models. There are assorted bugfixes and other minor enhancements.

New features include Xen Security Modules (XSM),
ACPI S3 suspend-to-RAM support for the host
system, preliminary PCI pass-through support
(using appropriate Intel or AMD I/O-virtualization
hardware), and preliminary support for a wider
range of bootloaders in fully virtualized (HVM)
guests, using full emulation of x86 real mode.
Emulation of standard (non-super) VGA modes for
HVM guests was made faster. Configurable timer
modes were added for HVM guests, depending on how
the guest OS manages time-keeping.