I have a asrock j4105(Gemini Lake) running esxi 6.7 u1, and I succeed passthrough IGD to a LibreELEC vm(will try Windows10 later)
as qemu document, it may running in UPT mode , which won't get video output , but my HDMI output works!
settings I changed is:
1. set bios mode to EFI
2. set svga.present to FALSE in vmx
It's magically works! hope this is helpful for you guys.