I have been using linux for 14 years as my main operating system. Today I use native ubuntu for productivity increase reasons. My systems and emulators are all natively installed on ubuntu. I really like VirtualBox to run my various virtual machines, I've been using it for many years and I've already tested other solutions like VirtualPC, VMWare and Parallels. I honestly don't see the need to pay for Parallels or VMWare because VirtualBox offers more than I could use in terms of features. I'm installing the B4X environment today and I chose to use a windows virtual machine for that. My only doubt would be in relation to android emulators, currently I use emulators provided natively by AVD Manager provided by AndroidStudio, I use it to test android APK compiled in IONIC and it works very well like that.
Therefore, I would like to run the ANdroid APK compilation with B4X on the windows virtual machine communicating with the emulated android via AVD on my native linux(ubuntu).
I don't know if that would be possible, but it would be perfect due to the performance gain at the hardware level.
But since you said that you use GenyMotion from Linux, it gave me hope knowing that you've already managed to do what I intend to do

If I can't get it my way, I'll try GenyMotion the way you said you're doing.