GVT-G + Wayland guest: garbled, pixelated, black white graphics

chaos_prevails · Today 14:49:58

Hello,

I have a E7470 laptop with skylake (i7-6650u with Iris 540) "9th" Gen Intel GPU and configured GVT-g according to the howto at archlinux: https://wiki.archlinux.org/title/Intel_GVT-g

passthrough works fine for a Windows 11 VM - I see the GPU correctly in device manager, etc. I've done it also on another E7450 with broadwell and GPU performance is notably better (under Windows).

here is my grub commandline:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash module.sig_enforce=yes intel_iommu=on iommu=pt i915.enable_guc=3 i915.enable_gvt=1 i915.enable_fbc=1 snd_hda_intel.align_buffer_size=1"

I know that in the archlinux documentation, it is written that gvt-g cannot be combined with guc/huc, but at least to my experience/testing, it still does: gvt-g works (in windows), and intel_gpu_top shows that my GPU is used when playing e.g. VP8 videos.

However, when trying to use the vGPU on a VM configured for wayland (tuxedo OS with wayland session), the screen gets garbled as soon as I login. When I logout, the problem disappears. When I switch the session to X11, the problem disappears as well (still using gpu passthrough).

My laptop runs Ubuntu 24.04 and is updated. I didn't find a lot of information about using wayland and GVT-g. I've tried these config settings (as found here: https://gitlab.freedesktop.org/mesa/mesa/-/issues/2678)

<qemu:commandline>
    <qemu:env name="INTEL_DEBUG" value="norbc"/>
  </qemu:commandline>

(setting MESA_LOADER_DRIVER_OVERRIDE to i965 or i915 results in an error)

But this doesn´t change a thing. I'm not sure where to look in the logfiles, which are hard to read having all this pixelation. So I was wondering if somebody can give me a pointer for what to look at?

Here is my qemu config:

<domain xmlns:qemu="http://libvirt.org/schemas/domain/qemu/1.0" type="kvm">
  <name>daron</name>
  <uuid>f3abbbfe-9eb6-4427-92fd-47c7f9b32279</uuid>
  <metadata>
    <libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
      <libosinfo:os id="http://ubuntu.com/ubuntu/24.04"/>
    </libosinfo:libosinfo>
  </metadata>
  <memory unit="KiB">4194304</memory>
  <currentMemory unit="KiB">4194304</currentMemory>
  <vcpu placement="static">2</vcpu>
  <os firmware="efi">
    <type arch="x86_64" machine="pc-q35-8.2">hvm</type>
    <firmware>
      <feature enabled="no" name="enrolled-keys"/>
      <feature enabled="yes" name="secure-boot"/>
    </firmware>
    <loader readonly="yes" secure="yes" type="pflash">/usr/share/OVMF/OVMF_CODE_4M.secboot.fd</loader>
    <nvram template="/usr/share/OVMF/OVMF_VARS_4M.fd">/var/lib/libvirt/qemu/nvram/daron_VARS.fd</nvram>
    <boot dev="hd"/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <vmport state="off"/>
    <smm state="on"/>
  </features>
  <cpu mode="host-passthrough" check="none" migratable="on">
    <topology sockets="1" dies="1" cores="2" threads="1"/>
  </cpu>
  <clock offset="utc">
    <timer name="rtc" tickpolicy="catchup"/>
    <timer name="pit" tickpolicy="delay"/>
    <timer name="hpet" present="no"/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <pm>
    <suspend-to-mem enabled="no"/>
    <suspend-to-disk enabled="no"/>
  </pm>
  <devices>
    <emulator>/usr/bin/qemu-system-x86_64</emulator>
    <disk type="file" device="disk">
      <driver name="qemu" type="qcow2" discard="unmap"/>
      <source file="/var/lib/libvirt/images/daron.qcow2"/>
      <target dev="vda" bus="virtio"/>
      <address type="pci" domain="0x0000" bus="0x04" slot="0x00" function="0x0"/>
    </disk>
    <disk type="file" device="cdrom">
      <driver name="qemu" type="raw"/>
      <target dev="sda" bus="sata"/>
      <readonly/>
      <address type="drive" controller="0" bus="0" target="0" unit="0"/>
    </disk>
    <controller type="usb" index="0" model="qemu-xhci" ports="15">
      <address type="pci" domain="0x0000" bus="0x02" slot="0x00" function="0x0"/>
    </controller>
    <controller type="sata" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1f" function="0x2"/>
    </controller>
    <controller type="pci" index="0" model="pcie-root"/>
    <controller type="pci" index="1" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="1" port="0x8"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0" multifunction="on"/>
    </controller>
    <controller type="pci" index="2" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="2" port="0x9"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x1"/>
    </controller>
    <controller type="pci" index="3" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="3" port="0xa"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x2"/>
    </controller>
    <controller type="pci" index="4" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="4" port="0xb"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x3"/>
    </controller>
    <controller type="pci" index="5" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="5" port="0xc"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x4"/>
    </controller>
    <controller type="pci" index="6" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="6" port="0xd"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x5"/>
    </controller>
    <controller type="pci" index="7" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="7" port="0xe"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x6"/>
    </controller>
    <controller type="pci" index="8" model="pcie-root-port">
      <model name="pcie-root-port"/>
      <target chassis="8" port="0xf"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x7"/>
    </controller>
    <controller type="virtio-serial" index="0">
      <address type="pci" domain="0x0000" bus="0x03" slot="0x00" function="0x0"/>
    </controller>
    <interface type="network">
      <mac address="52:54:00:f3:63:c9"/>
      <source network="default"/>
      <model type="virtio"/>
      <address type="pci" domain="0x0000" bus="0x01" slot="0x00" function="0x0"/>
    </interface>
    <serial type="pty">
      <target type="isa-serial" port="0">
        <model name="isa-serial"/>
      </target>
    </serial>
    <console type="pty">
      <target type="serial" port="0"/>
    </console>
    <channel type="unix">
      <target type="virtio" name="org.qemu.guest_agent.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>
    <channel type="spicevmc">
      <target type="virtio" name="com.redhat.spice.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="2"/>
    </channel>
    <input type="tablet" bus="usb">
      <address type="usb" bus="0" port="1"/>
    </input>
    <input type="mouse" bus="ps2"/>
    <input type="keyboard" bus="ps2"/>
    <tpm model="tpm-crb">
      <backend type="emulator" version="2.0"/>
    </tpm>
    <graphics type="spice">
      <listen type="none"/>
      <image compression="off"/>
      <gl enable="yes" rendernode="/dev/dri/by-path/pci-0000:00:02.0-render"/>
    </graphics>
    <sound model="ich9">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x1b" function="0x0"/>
    </sound>
    <audio id="1" type="spice"/>
    <video>
      <model type="none"/>
    </video>
    <hostdev mode="subsystem" type="mdev" managed="no" model="vfio-pci" display="on">
      <source>
        <address uuid="4d1cb2aa-f678-4516-b065-3059a218244b"/>
      </source>
      <address type="pci" domain="0x0000" bus="0x08" slot="0x00" function="0x0"/>
    </hostdev>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="2"/>
    </redirdev>
    <redirdev bus="usb" type="spicevmc">
      <address type="usb" bus="0" port="3"/>
    </redirdev>
    <watchdog model="itco" action="reset"/>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x06" slot="0x00" function="0x0"/>
    </memballoon>
    <rng model="virtio">
      <backend model="random">/dev/urandom</backend>
      <address type="pci" domain="0x0000" bus="0x07" slot="0x00" function="0x0"/>
    </rng>
  </devices>
  <qemu:commandline>
    <qemu:env name="INTEL_DEBUG" value="norbc"/>
  </qemu:commandline>
  <qemu:override>
    <qemu:device alias="hostdev0">
      <qemu:frontend>
        <qemu:property name="romfile" type="string" value="/usr/share/vgabios/vbios_gvt_uefi.rom"/>
        <qemu:property name="x-igd-opregion" type="bool" value="true"/>
        <qemu:property name="ramfb" type="bool" value="true"/>
        <qemu:property name="driver" type="string" value="vfio-pci-nohotplug"/>
        <qemu:property name="xres" type="unsigned" value="1024"/>
        <qemu:property name="yres" type="unsigned" value="768"/>
      </qemu:frontend>
    </qemu:device>
  </qemu:override>
</domain>

here is a sample image

Arch Linux

#1 Today 14:49:58

GVT-G + Wayland guest: garbled, pixelated, black white graphics

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