Reviewing Unused and Up-coming Hardware Virtualization Features

We review unused and up-coming hardware virtualization (Intel VT) features to discuss how they can improve virtualization for open source.

First, we review the existing hardware features that are not used by KVM or Xen today, showing examples for use cases.

1) For example, The descriptor-table exiting should be useful for the guest kernels or security agent to enhance security features. 2) The VMX-preemption timer allows the hypervisor to preempt guest VM execution after a specified amount of time, which is useful to implement fair scheduling. The hardware can save the timer value on each successive VM exit, after setting the initial VM quantum. 3) VMFUNC is an operation provided by the processor that can be invoked from VMX non-root operation without a VM exit. Today, EPTP switching is available, and we discuss how we can use the feature.

Second, we talk about the new hardware features, especially for interrupt optimizations.

Jun Nakajima is a Principal Engineer leading open source virtualization projects, such as Xen and KVM at the Intel Open Source Technology Center. He presented a number of times at technical conferences, including Xen Summit, OLS, KVM Forum, and USENIX.