VirtIO GPU DOD vs QXL

[benbaker76]

Is the VirtIO GPU DOD controller superior to the QXL controller? Is there any information you can provide in regard to the viogpudo driver and the performance differences?

Is there a signed version available to download?

Can you add support for these resolutions?

[vrozenfe]

As display only drivers both virtio-dod and qxl-dod are almost the same.
I don't have any performance numbers to compare viogpudod vs. qxldod,
but I did some GPU benchmark comparing viogpudod vs. in-box MSFT driver,
and the differences were extremely small.
As for me virtio gpu dod is a base for the future improvement and extension to
a Full Graphics or Render-Only WDDM driver https://docs.microsoft.com/en-us/windows-hardware/drivers/display/wddm-driver-and-feature-caps

Regarding to the signed drivers, you can try our latest drivers at
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/virtio-win-0.1.208-1/
All Win10 drivers there are attestation signed by Microsoft which should be enough to use those drivers
in UEFI setups.

Yes, it shouldn't be a problem to add the most of the resolutions from that list.
But just in case if you don't know, virtio-gpu provides dynamic resolutions changing
mechanism that supported by Windows driver. You just need to add and run some
binaries inside of your VM https://bugzilla.redhat.com/show_bug.cgi?id=1923886#c4
There only one restriction. The maximum size of the frame-buffer for Win10 platforms is
16MB at the moment which means that Height x Width should be less or equal 4MB
We have another issue opened for tracing this problem
#560

Best,
Vadim.

[benbaker76]

I was reading kraxel's blog post virtio-gpu and qemu graphics in 2021 regarding the new virtio-vga and virtio-vga-gl devices in qemu 6.1.

Second, blob resource support for the simple virtio-vga device is in progress, and it will bring support shared resource mappings to qemu. This will accelerate the display path due to less or no copying of pixel data.

Will the "blob resource support" improve the performance of this driver?

[vrozenfe]

You are probably asking about https://patchwork.kernel.org/project/dri-devel/patch/[email protected]/
Unfortunately, this feature will not be able to improve 2d rendering on Windows VMs

[BruceMok]

As for me virtio gpu dod is a base for the future improvement and extension to
a Full Graphics or Render-Only WDDM driver

Is any plan for this? I really need a full graphics WDDM driver because DOD driver's capability is so limited, more and more applications i can't run in VM(e.g. some application request VMR9).

[YanVugenfirer]

@BruceMok Sorry, the full graphics driver (with DirectX support) is not on a visible horizon.

[matheuswillder]

@BruceMok Sorry, the full graphics driver (with DirectX support) is not on a visible horizon.

@YanVugenfirer There are any open issue to track when this is added? Even if it takes a few years I'm interested in waiting, because I can't use GPU passthrough so this is the only thing that still holds me to VirtualBox.

[YanVugenfirer]

@matheuswillder I don't think there is an open issues. You can added.

In any case, technically QXL is not virtio-win driver and not managed in this repo, although our installer includes it. This is a project page: https://gitlab.freedesktop.org/spice/win32/qxl-wddm-dod

For virtio-gpu you can create an issue here.

[matheuswillder]

Okay thank you for the explanation. I searched before but only found #742 asking about 3D Acceleration in Windows 7. I opened a new issue about this here #773. Please feel free to suggest a better title for it if what I've created isn't good or if it's inaccurate (English is not my main language).

[YanVugenfirer]

@matheuswillder Thanks! The title looks OK.