The bulk of the changes here is for x86. And for once it's not for silicon that no one owns: these are really new features for everyone. * ARM: several features are in progress but missed the 4.2 deadline. So here is just a smattering of bug fixes, plus enabling the VFIO integration. * s390: Some fixes/refactorings/optimizations, plus support for 2GB pages. * x86: 1) host and guest support for marking kvmclock as a stable scheduler clock. 2) support for write combining. 3) support for system management mode, needed for secure boot in guests. 4) a bunch of cleanups required for 2+3. 5) support for virtualized performance counters on AMD; 6) legacy PCI device assignment is deprecated and defaults to "n" in Kconfig; VFIO replaces it. On top of this there are also bug fixes and eager FPU context loading for FPU-heavy guests. * Common code: Support for multiple address spaces; for now it is used only for x86 SMM but the s390 folks also have plans. There are some x86 conflicts, one with the rc8 pull request and the rest with Ingo's FPU rework.