Loading virtio-input-host-pci drivers before boot? To allow using passthrough devices in grub and other preboot menus?

Currently virtio-input devices cannot be used before the kernel loads.  This is not really a full bug but it would be much more useful if you can use the keyboard+mouse this way.

This can not be fixed on the QEMU side. If you want to have virtio-input support in seabios or grub for example, you've got to ask the seabios or grub project to add it.