As a quick refresher, PVHVM is the Hardware Assisted Virtualization for Xen that's supported in conjunction with specialized drivers that are common to most modern Linux distributions and is an alternative to Xen's classic PV (para-virtualized) configuration. If you are unfamiliar, you can read more via the Xen Wiki.
The Xen Orchestra crew ran some fresh benchmarks to succeed the numbers they put out two years ago. As with their previous results, they utilized the Phoronix Test Suite for this fresh round of Xen PV vs. PVHVM benchmarking.
Their results show PVHVM now winning by a larger gap than previously with the newer hardware having more virtualization instructions with less overhead compared to older hardware. In worst case scenario, the PVHVM performance matches PV but in best case was around 40% faster on their Core i5 Haswell hardware. More details via this Xen Orchestra blog post.