For the main linked benchmark there are no dedicated test hypervisors. It's all based on GH runners with all the limitations and quirks that came with it.

Real hardware is used in: https://bartosz.fenski.pl/modern-fs-benchmark/real-hw/ https://bartosz.fenski.pl/modern-fs-benchmark/sas-hdd/

But unfortunatelly it's much more limited number of actual runs. sas-hdd is still in progress so numbers for it should increase over time.