For "disk access" I assume that is for folder sharing? However I don't understand the "internet connection" part, can you elaborate? Thank you!
@Mark Fine, I would argue that the connectivity can be achieved by emulating e1000e (which is supported by the stock kernels) and that if one wants to run console only VM then the only benefit they would get from Parallels Tools would be the ability to mount shared folders (and, as you correctly pointed out, better disk I/O).
I am running Ubuntu and selected nvme when creating the vm. I installed the tool now and, the network drive is virtio-pci, storage driver is nvme. I think those are the same before and after I install the tool.
AFAIK there are no tools related to network or disk subsystem for Linux. The only reason to install tools is to get video resolution higher then default 1024x768
Incorrect. Look at the code, which hooks virtually all I/O to make it seamless with Darwin. In fact two modules deal for the majority with disk I/O.