First, make sure the iommu and vfio features are enabled. If not, see here.
Step1. Download the vgabios romfile for HD600 and copy it to /usr/share/kvm
Step2. Edit your VM config file at /etc/pve/qemu-server/[vmid].conf
#add or edit # args: -device vfio-pci,host=00:02.0,addr=0x02,x-igd-gms=1,romfile=HD600.bin vga: none #
Done! Try to start your vm and enjoy it. If there is any problem on boot. Select the OVMF(UEFI) Bios may will fix it.
If there is a problem of ‘failed to open /dev/vfio/1: No such file or directory’. It means the vfio isn’t configured correctly. This may caused by vfio-pci is no longer a module but compiled-in since kernel 4.18.16.