From a test I conducted this week, I observed a problem with the HPET driver and the E1000 driver when trying to boot Serenity in VirtualBox.
How to reproduce:

1. Create a vdi image (https://docs.oracle.com/en/virtualization/virtualbox/6.1/user/vboxmanage-convertfromraw.html), after you created a grub image with build-image-grub.sh.
2. To check if HPET is not working, create a new VM, import the image you created and in the settings of the machine, switch the Chipset to ICH9 instead of PIIX3. Run the machine, it should exit with an error. With the Chipset being set to PIIX3 there's no problem booting Serenity.
3. To check if E1000 driver is not working, switch the chosen adapter type to be 82540EM. I booted with the same card type within Archlinux ISO, and I verified that this type corresponds to be PCI 8086:100e.

It is very possible that the QEMU variant of E1000 card is different from the one in VirtualBox (a different model in the E1000 cards' family).

Also, @jcs mentioned a problem with the HPET driver on his Thinkpad x61.
Clearly, we have problems with both of these drivers.