Migrating from KVM for IBM z to SLES12

In case you are contemplating a migration from KVM for IBM z to SLES12 SP2 or later, you might find the instructions published by SuSE here helpful.

QEMU v2.9 released

QEMU v2.9 is out. Here are the highlights from a KVM on z perspective:

• Added support for virtio-crypto, providing a virtual crypto device as a front-end to the host's crypto capabilities on z Systems.
• Added multiqueue support for virtio-ccw devices, improving throughput in presence of multiple processors.
• Provided network boot enablement. See here for further details.

Linux kernel 4.11 released

Linux kernel 4.11 (available here) has been released, improving Kernel Samepage Merging (KSM) support for KVM on z:

KSM is an existing feature of the Linux kernel that allows the kernel to merge pages with identical content, indicated as MADV_MERGEABLE via madvise(), across different processes to save memory.
This z Systems specific extension improves the performance of userspace applications (e.g. QEMU) in case large amounts of empty/zeroed pages are merged.
This feature is disabled by default, enable as follows:

   $ echo 1 > /sys/kernel/mm/ksm/use_zero_pages