Xen 4.2 Feature List
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High Level features
- Security:
- Support for Intel Supervisor Mode Execution Protection (SEMP), which prevents the execution usermode of pages by the Xen hypervisor, making many application-to-hypervisor exploits much harder.
- Various Xen Security Modules (XSM) / Flask improvements. The XSM framework and the Xen Flask security module is an application of the Flask architecture to the Xen hypervisor.
- Scalability:
- Increased VM density for VDI use-cases
- up to 256 Host CPUs for 64 bit HV
- Multiple PCI segment support
- Prefer oxenstored when present
- Performance
- PCI pass-through for Linux Guests
- AMD SVM DecodeAssist support
- Remus memory image compression
- New scheduler parameters [1]
- EFI support
- Libvchan cross domain comms in Xen mainline
- XL improvements, XEND is formally deprecated
- Documentation improvements (e.g. man pages)
- RAS:
- Enhanced MCA support to include more failure types
- APEI support (ACPI Platform Error Interface)
Detailed List
General
- Documentation improvements (e.g. man pages)
- Lots of bug fixing of course.
Tools
- xl is now default toolstack and xend is formally deprecated
- lots of xl improvements, e.g.
- Support for Network driver domains in xl
- we should highlight xend deprecation (not effectively maintained since 2008)
- lots of xl improvements, e.g.
- Remus compression (compression of memory image improves performance)
- Prefer oxenstored when available (improves scalability!)
- Support for upstream qemu; nearing feature parity (non default still, but we want people to be testing it)
- Added libvchan to xen mainline(cross domain comms)
Xen
- Improvements to paging and sharing, enabling higher VM density for VDI use-cases
- EFI (extensible Firmware Interface) support for HV (i.e. if I have a machine that has EFI, I can use Xen on it)
- Support up to 256 Host CPUs for 64 bit h/v (from 128)
- Support dom0 kernels compressed with xz
- Per-device interrupt remapping (increases scalability)
- Support for pvhvm guest direct pirq injection (Performance improvement for PCI passthrough for Linux Guests)
- Intel SMEP (Supervisor Mode Execution Protection) support
- Mem event stuff? (Allows to externally observe what guests are up to and can be used for external virus checking - not sure what the right terminology is)
- Multiple PCI segment support
- Added xsave support(floating point)
- Lots of XSM / Flask fixes (security)
- AMD SVM "DecodeAssist" support (AMD CPU feature that avoids emulation and increases performance)
- RAS:
- Enhanced MCA support to include more failure types
- APEI support (ACPI Platform Error Interface)
- New scheduler parameters [2]
Removed Functionality
- ACM (alternative XSM to Flask) was removed (unmaintained)
- Removed vnet (unmaintained)
- The IA64 port was removed (unmaintained)
Xen Development Support
- Can build with clang
- Added "make deb" target
- Lots of xentrace improvements
- update ocaml bindings and make them usable by xapi (which previously had it's own fork of the same codebase)
Also See
- Category:Xen 4.2 - Contains articles and tutorials related to new functionality in Xen 4.2