In yet another impressive feat, KVM’s release today supports hardware assisted memory virtualization feature called Extended Page Tables (EPT) to be released on future intel chips codenamed Nehalem. AMD’s version of this is called Nested Page Tables which KVM supported from release 61. This technology will allow VM guests to see their own contiguous memory address space although it is not actually contiguous on the underlying hardware. The guest OS will actually store the mapping of virtual to physical memory addresses in page tables.

This should really improve guest performance significantly as more partitioning is done by hardware. I would sure like to have one of those running on my laptop or even just a prototype for testing. However, you’ll have to wait till late 2008 to see Nehalem in high end chips and 2009 before seeing it in mainstream chips if you’re interested in getting one.

Below is an excerpt of the changelog as posted on the devel mailing list.

Changes from kvm-67:
- Intel EPT support (Sheng Yang)
- Code cleanups (Harvey Harrison)
- Fix task switch busy bit setting (Izik Eidus)
- Reduce guest idle cpu usage on ppc (Hollis Blanchard)
- Support floating point instructions on ppc (Christian Ehrhardt)
- Fix lmsw emulation
- fixes host oops on AMD
- Add PIT mode 4 support (Marcelo Tosatti)
- fixes DragonflyBSD
- Avoid spurious exceptions on state reload (Jan Kiszka)
- Add SVM kvmtrace support (Joerg Roedel)
- Avoid schedule-in-atomic on 2.6.26 hosts (Andrea Arcangeli)
- Handle vma regions with no backing page (Anthony Liguori)
- yet another step on the way to pci device assignment
- move external module compatibility code into .c file
- build: sync non-x86 kvm headers
- avoid using kernel headers; use installed libc headers instead
- don't exit iothread berfore all vcpus are stopped (Dor Laor)
- libkvm uninitialized variable fix (Marcelo Tosatti)
- remove old user/config.mak (Jerone Young)
- fix vcpu startup race (Anthony Liguori)
- dump all libkvm errors to stderr (Jan Kiszka)
- fix cross-compilation (Jerone Young)
- fix kvm_show_code() to work on ROM and real-mode (Jan Kiszka)
- allow qemu -kernel option with extboot (Mark McLoughlin)

You can download KVM-68 here.