Today Proxmox releases version 1.5 of it's VE product featuring memory overcommit support for KVM using KSM. In an earlier post I wrote about using KSM for memory overcommit with KVM. This release features support for three linux kernel branches. Only the 2.6.32 branch supports KSM which is expected since KSM was only recently added to this linux kernel version. Proxmox lists the following features with this latest release

•  support different kernel versions
• new 2.6.18 Linux kernel - default (OpenVZ, KVM)
• new 2.6.24 Linux kernel (OpenVZ, KVM)
• new 2.6.32 Linux kernel (KVM only, KSM support)
• use update-initramfs
• DRBD: update to drbd 8.3.4
• AOE: update to AOE6-73
• SCST: update to latest SCST modules
• new KVM user-space tools
• we now use the qemu-kvm stable branch (0.11.1)
• new virtual packages for better kernel dependency handling - proxmox-ve-2.6.18, proxmox-ve-2.6.24 and proxmox-ve-2.6.32
• updated most appliances
• installation CD now use/install proxmox-ve-2.6.18
• updated vzctl, with improved init-logger patch
• updated Russian and Japanese translation
• many other small improvements and bug fixes

You can read more at the following link.

http://pve.proxmox.com/wiki/Proxmox_VE_News