[vfio-users] Help on IGD legacy, VBIOS and OPS HDMI

[Chen Zhang]

Hi,


I'm trying to configure kvm to pass through IGD (skylake 6100 with HD530) in legacy mode. The mainboard has an OPS (Intel Open Pluggable Spec [1]) connector, which is an 80-pin connector including HDMI output.



Besides one DP(VGA) and one HDMI on board, the mainboard provides ports for display links (DP-1, HDMI-A-1, HDMI-A-2 as reported in kernel log by i915). Xorg utilized these ports smoothly.



The trouble is that when the IGD is assigned with OPS-HDMI (HDMI-A-1) as primary display in mainboard BIOS (CSM of course), kvm would not boot and halt with a 100% CPU usage.


If a romfile dumped[2] before assignment is used in -device options, the kvm would boot regardless of the primary display configuration, but the output of SeaBIOS POST and initial stage of booting (i.e. the Windows 10 logo before login screen) would not be available. It is speculated that the displays would not be detected correctly until the guest driver took over.



--------------------

The arguments for kvm (qemu-2.10.1):



/usr/local/bin/qemu-system-x86_64 -name vm1 \
 -nodefaults \
 -machine pc,igd-passthru=on,accel=kvm,usb=off \
 -global PIIX4_PM.disable_s4=0 \
 -global PIIX4_PM.disable_s3=1 \
 -global ICH9-LPC.disable_s3=1 \
 -global ICH9-LPC.disable_s4=0 \
 -enable-kvm -rtc base=localtime \
 -nographic -vga none \
 -m 3000m -realtime mlock=off -smp 4,sockets=1,cores=2 \
 -device vfio-pci,host=00:02.0,id=hostdev0,bus=pci.0,addr=0x2,x-vga=on,x-igd-gms=6,romfile=/root/vbios1 \
 -drive file=/root/disks/test.img,media=disk,if=none,id=drive-c \
 -device ide-hd,bus=ide.0,unit=0,drive=drive-c,bootindex=0 \
 -no-user-config \
 -cpu host,kvm=off


The kernel (ubuntu 16.04/4.15.0-13-generic) arguments:



ro quiet splash intel_iommu=on iommu=pt drm.debug=0xe vt.handoff=7


The version/build of Intel VBIOS is 1040.



[1] https://www.intel.com/content/www/us/en/embedded/retail/digital-signage/open-pluggable-specification/overview.html



[2] https://01.org/zh/linuxgraphics/documentation/development/how-dump-video-bios?langredirect=1


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