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IGVT-g: Difference between revisions

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imported>Gnidorah
Created page with "Intel GVT-g is a full GPU virtualization solution with mediated pass-through which allows host and multiple guests to share same Intel integrated videocard. Guest gets a near-..."
 
imported>Whazor
Add note about GVT-g removal and SR-IOV future
 
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Intel GVT-g is a full GPU virtualization solution with mediated pass-through which allows host and multiple guests to share same Intel integrated videocard. Guest gets a near-native graphics peformance.
Intel GVT-g is a technology that allows to "slice" an Intel GPU into virtualized GPUs that can be then passed into virtual machines.


Win7-32 / Win7-64 / Win8.1-64 /Win10-RS1-64 are validated. Install recent Intel driver into the guest.
Note that Intel GVT-g only supports Intel Broadwell (5th gen) to Comet Lake (10th gen), where in 10th gen support for IVGT-g was removed. For 11th gen, and 12th gen, there is SR-IOV coming up for virtualized GPUs, but that did not yet arrive in Linux mainline.


== Hardware Requirements ==
== Configuring GPU ==


For client platforms, 5th, 6th or 7th Generation Intel® Core Processor Graphics is required. For server platforms, E3_v4, E3_v5 or E3_v6 Xeon Processor Graphics is required.
First, enable iGVT-g with:


== NixOS configuration ==
{{file|/etc/nixos/configuration.nix|nix|<nowiki>
virtualisation.kvmgt.enable = true;
</nowiki>}}
... then rebuild and reboot.


/etc/nixos/configuration.nix
  boot.kernelPackages = pkgs.linuxPackages_4_16;
  boot.kernelParams = [ "i915.enable_gvt=1" ];
  nixpkgs.config.packageOverrides = super: let self = super.pkgs; in {
    linux_4_16 = super.linux_4_16.override {
      extraConfig = ''
  # since 4.16-rc1
  DRM_I915_GVT y
  DRM_I915_GVT_KVMGT m
      '';
    };
  };
  environment.systemPackages = with pkgs; [
  virtmanager
  virt-viewer
  libossp_uuid
  ];
  virtualisation.libvirtd.enable = true;
  users.extraUsers.'''user'''.extraGroups = [ "libvirtd" ];


== Create or destroy VGPU ==
After rebooting, check if the driver was successfully loaded:
 
  $ ls /sys/bus/pci/devices/0000:00:02.0/mdev_supported_types/
 
... if you get <code>No such file or directory</code>, it means you might be using an older CPU that needs an extra configuration option:
 
{{file|/etc/nixos/configuration.nix|nix|<nowiki>
boot.extraModprobeConfig = "options i915 enable_guc=2";
</nowiki>}}
... then rebuild and reboot once again (unless that previous <code>ls</code> succeeded, in which case you don't have to modify that <code>extraModprobeConfig</code> at all).
 
 
Now, using <code>ls</code> you can list which variants your Intel GPU is able to virtualise:
 
  $ ls /sys/bus/pci/devices/0000:00:02.0/mdev_supported_types/
  i915-GVTg_V5_4/  i915-GVTg_V5_8/
 
E.g.:


Show mode information
  $ cat /sys/bus/pci/devices/0000:00:02.0/mdev_supported_types/i915-GVTg_V5_8/description
  low_gm_size: 64MB
  high_gm_size: 384MB
  fence: 4
  resolution: 1024x768
  weight: 2


<pre>
Find some variant that matches your expectations (resolution, memory size etc.), note down its name, generate a random UUID:
$ cat /sys/bus/pci/devices/0000:00:02.0/mdev_supported_types/i915-GVTg_V5_8/description
low_gm_size: 64MB
high_gm_size: 384MB
fence: 4
resolution: 1024x768
weight: 2
</pre>


Create
  # If you're using Nix Flakes:
  $ nix shell nixpkgs#libossp_uuid -c uuid
  a297db4a-f4c2-11e6-90f6-d3b88d6c9525


<pre>
  # If you're not using Nix Flakes:
# uuid
  $ nix run nixpkgs.libossp_uuid -c uuid
a297db4a-f4c2-11e6-90f6-d3b88d6c9525
  a297db4a-f4c2-11e6-90f6-d3b88d6c9525
# echo "a297db4a-f4c2-11e6-90f6-d3b88d6c9525" > "/sys/bus/pci/devices/0000:00:02.0/mdev_supported_types/i915-GVTg_V5_8/create"
</pre>


Destroy
... and add that variant's name into your configuration:


<pre>
{{file|/etc/nixos/configuration.nix|nix|<nowiki>
# echo 1 > /sys/bus/pci/devices/0000:00:02.0/a297db4a-f4c2-11e6-90f6-d3b88d6c9525/remove
virtualisation.kvmgt.enable = true;
</pre>
virtualisation.kvmgt.vgpus = {
  "i915-GVTg_V5_8" = {
    uuid = [ "a297db4a-f4c2-11e6-90f6-d3b88d6c9525" ];
  };
};


== Configure KVM ==
environment.systemPackages = with pkgs; [
  virtmanager
];


Support for local display is present in Qemu 2.12. Only BIOS (SeaBIOS) machine is supported, UEFI (OVMF) is not supported.
virtualisation.libvirtd.enable = true;
users.extraUsers.user.extraGroups = [ "libvirtd" ];
</nowiki>}}
 
Rebuild & voilá - your virtualized GPU is ready; now you just have to attach it to some virtual machine.
 
== Attaching GPU ==


=== Bare Qemu ===
=== Bare Qemu ===
   qemu-system-x86_64 \
   qemu-system-x86_64 \
     -enable-kvm \
     -enable-kvm \
     -m 1G \
     -m 1G \
     -nodefaults \
     -nodefaults \
    -M graphics=off \
    -serial stdio \
     -display gtk,gl=on \
     -display gtk,gl=on \
     -device vfio-pci,sysfsdev=/sys/bus/mdev/devices/'''a297db4a-f4c2-11e6-90f6-d3b88d6c9525''',x-igd-opregion=on
     -device vfio-pci,sysfsdev=/sys/bus/mdev/devices/'''a297db4a-f4c2-11e6-90f6-d3b88d6c9525''',display=on,x-igd-opregion=on,driver=vfio-pci-nohotplug,ramfb=on,xres=1920,yres=1080
 
=== libvirt ===


=== libvirtd ===
If using virt-manager, create new or open existing VM. Change existing <code><graphics></code> and <code><video></code> sections.
If using virt-manager, create new or open existing VM. Its impossible to remove primary QXL videocard, but it will conflict, so change it to Cirrus.


sudo -E virsh edit '''win10'''
sudo -E virsh edit win10
<domain type='kvm' '''xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0''''>
<syntaxHighlight lang="xml" highlight="1,12">
<nowiki><!-- ... --></nowiki>
<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
<devices>
  <devices>
<nowiki><!-- ... --></nowiki>
    <graphics type='spice'>
<graphics type='spice'>
      <listen type='none'/>
  <listen type='none'/>
      <gl enable='yes'/>
  <nowiki><!-- choose renderer via virt-manager --></nowiki>
    </graphics>
  <gl enable='yes'/>
    <video>
</graphics>
      <model type='none'/>
<'''hostdev''' mode='subsystem' type='mdev' managed='no' model='vfio-pci'>
    </video>
  <nowiki><source></nowiki>
    <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-pci' display='on'>
    <address uuid=''''a297db4a-f4c2-11e6-90f6-d3b88d6c9525''''/>
      <source>
  <nowiki></source></nowiki>
        <address uuid='a297db4a-f4c2-11e6-90f6-d3b88d6c9525'/>
  <nowiki><!-- assign to first available slot --></nowiki>
      </source>
  <address type='pci' domain='0x0000' bus='0x00' slot=''''0x05'''' function='0x0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/>
</hostdev>
    </hostdev>
</devices>
  </devices>
   <qemu:commandline>
   <qemu:commandline>
  <qemu:arg value='-set'/>
    <qemu:arg value='-set'/>
  <qemu:arg value='device.'''hostdev0'''.x-igd-opregion=on'/>
    <qemu:arg value='device.hostdev0.x-igd-opregion=on'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.ramfb=on'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.driver=vfio-pci-nohotplug'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.xres=1920'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.yres=1080'/>
    <qemu:env name="MESA_LOADER_DRIVER_OVERRIDE" value="i965"/>
   </qemu:commandline>
   </qemu:commandline>
</domain>
</domain>
</syntaxHighlight>
 
== FAQ ==
 
* No video output
 
** use BIOS (SeaBIOS) machine, EFI (OVMF) is not supported. You may use the following workarounds https://wiki.archlinux.org/index.php/Intel_GVT-g#Using_DMA-BUF_with_UEFI/OVMF
 
** ensure that the recent Intel graphics driver is installed in the guest
 
* (libvirtd) "Element domain has extra content: qemu:commandline" error after editing via virsh
 
** you forgot to add <nowiki>xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'</nowiki>
 
* (libvirtd) "no drm render node available" error in virt-manager
 
** in virt-manager change SPICE display render node from auto to available one
 
* "write_loop: No space left on device" error when creating mdev device
 
** check whether available instances are left
  $ cat /sys/bus/pci/devices/0000\:00\:02.0/mdev_supported_types/i915-GVTg_V5_4/available_instances
  1
also check dmesg output for gvt related error, most likely there is not enough VRAM
 
* (libvirtd) VM stops immediately with no error other than "internal error: process exited while connecting to monitor"
 
** qemu might be exiting due to SIGSYS, which may be related to this bug: https://github.com/intel/gvt-linux/issues/47
Try disabling seccomp sandboxing in qemu like so:
<syntaxHighlight lang="nix">
  virtualisation.libvirtd = {
    qemuVerbatimConfig = ''
      seccomp_sandbox = 0
    '';
  };
</syntaxHighlight>
== Useful sources ==


Finally use sudo virt-viewer --attach '''win10'''
* https://www.kraxel.org/blog/2019/02/ramfb-display-in-qemu/ - Info about ramfb parameter
* https://lists.01.org/hyperkitty/list/igvt-g@lists.01.org/thread/LAB74CANVVRKGPBJMHULMMUFX43LRH55/ - Info about x-igd-opregion parameter
* https://www.kraxel.org/blog/2019/03/edid-support-for-qemu/ - Info about xres and yres parameters
[[Category:Video]]
[[Category:Virtualization]]
Retrieved from "https://wiki.nixos.org/wiki/IGVT-g"