Linux guest on bhyve graphic driver

I am running arch Linux guest via bhyve. I already installed xorg-server and xorg-xinit on the guest. But I am not sure which graphic driver I should install and I don't know if I have to install any graphic components at the host as well?
I don't really get what UEFI-Firmware boot has to do with running a desktop environment in the guest system. If I boot a bhyve vm via GRUB, then why I can't run a desktop environment? Could you please give me short explanations?