Xen Project Release Features
Legend: ✓: Feature ✓: Partial
| Xen 4.0 | Xen 4.1 | Xen 4.2 | Xen 4.3 | |
|---|---|---|---|---|
| Initial Release | 7 April 2010 | 25 March 2011 | 17 September 2012 | 9 July 2013 |
| Feature List | FL 4.2 | FL 4.3 | ||
| Release Notes | RN 4.0 | RN 4.1 | RN 4.2 | RN 4.3 |
| Supported Mainline Architectures for the hypervisor (Host) | ||||
| IA-A32 | ✓ | ✓ | ✓ | Removed |
| X86-64 | ✓ | ✓ | ✓ | ✓ |
| Itanium (ia64) | ✓ | ✓deprecated in this release | ✓deprecated | Removed |
| ARM v7 + Virtualization Extensions | ✓tech preview [ 6 ] | |||
| ARM v8 | ✓tech preview [ 6 ] | |||
| Guest Types | ||||
| For X86 Architectures | ||||
| Paravirtualised Traditional Xen PV guest |
✓ | ✓ | ✓ | ✓ |
| HVM Guest [ 1 ] Fully virtualised guest using hardware virtualisation extensions |
✓ | ✓ | ✓ | ✓ |
| PV-on-HVM Guest [ 1 ] Fully virtualised guest using PV extensions/drivers for improved performance |
✓ | ✓ | ✓ | ✓ |
| For ARM Architectures | ||||
| ARM Guest Optimal combination of full virtualization and PV extensions |
✓tech preview [ 6 ] | |||
| Host Limits | ||||
| For X86 Architectures | ||||
| Physical CPUs | 128 [ 0 ] | >255 | 4095 | 4095 |
| Physical RAM | 1TB | 5TB | 5TB | 16TB |
| For ARM Architectures | ||||
| Physical CPUs | 8 | |||
| Physical RAM | 16GB | |||
| Guest Limits | ||||
| X86 PV Guest Limits | ||||
| Virtual CPUs | 128 | >255 | 512 | 512 |
| Virtual RAM | 512GB | 512GB | 512GB | 512GB |
| X86 HVM Guest Limits | ||||
| Virtual CPUs | 128 | 128 | 256 | 256 |
| Virtual RAM | 1TB | 1TB | 1TB | 1TB |
| ARM Guest Limits | ||||
| Virtual CPUs | 8 | |||
| Virtual RAM | 16GB | |||
| Toolstack | ||||
| Built-in | ||||
| xend / xm | ✓ | ✓ | ✓deprecated in this release | ✓deprecated |
| XL | ✓initial implementation | ✓preview release | ✓ | ✓ |
| Qemu based disk backend (qdisk) for XL |
✓ [ 5 ] | ✓ [ 5 ] | ✓ [ 5 ] | |
| XL Open vSwitch integration | ✓tech preview [ 7 ] | |||
| 3rd Party | ||||
| libvirt driver for XL | ✓ | ✓ | ✓ | |
| Features | ||||
| Advanced Memory Management | ||||
| Memory Ballooning | ✓ | ✓ | ✓ | ✓ |
| Memory Sharing allow sharing of identical pages between HVM guests |
✓tech preview | ✓tech preview | ✓tech preview [ 3 ] | ✓tech preview [ 3 ] |
| Memory Paging allow pages belonging to HVM guests to be paged to disk |
✓tech preview | ✓tech preview | ✓tech preview [ 3 ] | ✓tech preview [ 3 ] |
| TMEM - Transcendent Memory | ✓experimental [ 2 ] | ✓experimental [ 2 ] | ✓experimental [ 2 ] | ✓experimental [ 2 ] |
| Resource Management | ||||
| Cpupool advanced partitioning |
✓ | ✓ | ✓ | |
| Credit 2 Scheduler designed for latency-sensitive workloads and very large systems. |
✓prototype | ✓prototype | ✓experimental | |
| NUMA scheduler affinity | ✓ | |||
| Scalability | ||||
| 1GB/2MB super page support | ✓ | ✓ | ✓ | |
| Deliver events to PVHVM guests using Xen event channels | ✓ | ✓ | ✓ | |
| Interoperability / Hardware Support | ||||
| Nested Virtualisation Running a hypervisor inside an HVM guest |
✓experimental | ✓experimental | ||
| HVM PXE Stack | gPXE | iPXE | iPXE | iPXE |
| Physical CPU Hotplug | ✓ | ✓ | ✓ | ✓ |
| Physical Memory Hotplug | ✓ | ✓ | ✓ | ✓ |
| Support for PV kernels in bzImage format | ✓ | ✓ | ✓ | ✓ |
| PCI Passthrough | ✓ | ✓ | ✓ | ✓ |
| X86 Advanced Vector eXtension (AVX) | ✓ [ 4 ] | ✓ | ✓ | |
| High Availability and Fault Tolerance | ||||
| Live Migration, Save & Restore | ✓ | ✓ | ✓ | ✓ |
| Remus Fault Tolerance | ✓ | ✓ | ✓ | ✓ |
| vMCE Forward Machine Check Exceptions to Appropriate guests |
? | ? | ✓ | ✓ |
| Network and Storage | ||||
| Blktap2 | ✓ | ✓ | ✓ | ✓ |
| Online resize of virtual disks | ✓ | ✓ | ✓ | ✓ |
| Security (also see this presentation or this document) | ||||
| Driver Domains | ✓ | ✓ | ✓ | ✓ |
| Device Model Stub Domains | ✓ | ✓ | ✓ | ✓ |
| Memaccess API enabling integration of 3rd party security solutions into Xen virtualized environments |
✓ | ✓ | ✓ | |
| XSM & FLASK mandatory access control policy providing fine-grained controls over Xen domains, similar to SELinux |
✓ | ✓ | ✓ | ✓ |
| XSM & FLASK support for IS_PRIV | ✓ | |||
| vTPM Support |
✓ | ✓ | ✓ | ✓ updates and new functionality |
| Tooling | ||||
| gdbsx debugger to debug ELF guests |
✓ | ✓ | ✓ | ✓ |
| vPMU Virtual Performance Management Unit for HVM guests |
✓ [ 4 ] | ✓ [ 4 ] | ✓ [ 4 ] | ✓ [ 4 ] |
| Serial console | ✓ | ✓ | ✓ | ✓Add EHCI debug support |
| xentrace performance analysis |
✓ | ✓ | ✓ | ✓ |
| Device Models and Virtual Firmware for HVM guests | ||||
| For X86 Architectures | ||||
| Traditional Device Model Device emulator based on Xen fork of Qemu |
✓ | ✓ | ✓ | ✓ |
| Qemu Upstream Device Model Device emulator based on upstream Qemu |
✓tech preview | ✓default, unless stubdomains are used | ||
| ROMBIOS BIOS used with traditional device model only |
✓ | ✓ | ✓ | ✓ |
| SeaBIOS BIOS used with upstream qemu device model and XL only |
✓ | ✓ | ||
| OVMF/Tianocore UEFI Firmware used with upstream qemu device model and XL only |
✓experimental [ 4 ] | ✓experimental [ 4 ] | ||
| PV Bootloader support | ||||
| For X86 Architectures | ||||
| PyGrub support for GRUB 2 | ✓ | ✓ | ✓ | ✓ |
| PyGrub support for /boot on ext4 | ✓ | ✓ | ✓ | ✓ |
| pvnetboot support Bootloader supporting network boot of PV guests |
✓ | ✓ | ||
[ 0 ] Compile time limit, can be increased
[ 1 ] Requires hardware virtualisation support
[ 2 ] Disabled by default (enable with hypervisor command line option). Not supported in production and doesn't have full security support
[ 3 ] Preview, due to limited tools support. Hypervisor side in good shape
[ 4 ] Disabled by default (enable with hypervisor command line option)
[ 5 ] Used as a fallback if blkback and/or blktap2 are not available
[ 6 ] See Xen ARM with Virtualization Extensions; basic functionality implemented; lack of real hardware to validate against
[ 7 ] tech preview, depending on test coverage in Xen Test Days
