bhyve: Warning: Unable to reuse host address of Graphics Stolen Memory. GPU passthrough might not work properly. bhyve: gvt_d_setup_opregion: Unable to get OpRegion base and length bhyve: gvt_d_init: Unable to setup OpRegion device emulation initialization error: Operation not supported by device

Hello.

I've tried to passthru my CoffeeLake-S GT2 [UHD Graphics 630] on a Linux VM
but it failed. This graphic card :

ppt4@pci0:0:2:0:        class=0x038000 rev=0x02 hdr=0x00 vendor=0x8086
device=0x3e98 subvendor=0x1458 subdevice=0xd000
   vendor     = 'Intel Corporation'
   device     = 'CoffeeLake-S GT2 [UHD Graphics 630]'
   class      = display

below there are the bhyve parameters that I've used :

bhyve -S -c sockets=1,cores=2,threads=2 -m 4G -w -H -A \
-s 0,hostbridge \
-s 1,nvme,/dev/$vmdisk0,bootindex=1 \
-s 2,ahci-hd,/dev/$vmdisk2 \
-s 3,ahci-hd,/dev/$vmdisk4 \
-s 4,passthru,0/2/0 \
-s 7,virtio-net,tap4 \
-s 10,hda,play=/dev/dsp,rec=/dev/dsp \
-s 29,fbuf,tcp=0.0.0.0:5904,w=1500,h=950 \
-s 30,xhci,tablet \
-s 31,lpc \
-l bootrom,/usr/local/share/uefi-firmware/BHYVE_BHF_CODE.fd \
vm4 < /dev/null & sleep 2 && vncviewer 0:4

this is the error I get :

bhyve: Warning: Unable to reuse host address of Graphics Stolen Memory.
GPU passthrough might not work properly.
bhyve: gvt_d_setup_opregion: Unable to get OpRegion base and length
bhyve: gvt_d_init: Unable to setup OpRegion
device emulation initialization error: Operation not supported by device

Should I apply some patches ? I know for sure that I can pass through this
kind of gpu,using the Corvin patches,but I don't know if I have found a bug
that should be fixed. Let me know.

-- 
Mario.