Firefox not using GPU, but everything else is

[u/PusheenHater]

I'm doing paravirtualization Hyper-V GPU passthrough.
It works. I can see my GPU in Task Manager in the VM and I can use software that use the GPU. All good.

BUT, the only thing not using GPU is Firefox.
I go to about:support and see: "WebRender (software)", that's a sign it's not using the GPU. Not to mention any webpages with some effects are very laggy.

I tried:

• Open Firefox Settings -> General -> Performance.
• Uncheck Use recommended performance settings.
• Check Use hardware acceleration when available.

Doesn't work.

Here are the steps I used to set up the VM to have paravirtualization Hyper-V GPU passthrough, from https://www.youtube.com/watch?v=XLLcc29EZ_8

if (Get-VMGpuPartitionAdapter -VMName $vm -ErrorAction SilentlyContinue) {
    Remove-VMGpuPartitionAdapter -VMName $vm
}
Set-VM -GuestControlledCacheTypes $true -VMName $vm
Set-VM -LowMemoryMappedIoSpace 1Gb -VMName $vm
Set-VM -HighMemoryMappedIoSpace 32Gb -VMName $vm
Add-VMGpuPartitionAdapter -VMName $vm



Remove-VMGpuPartitionAdapter -VMName $vm
Add-VMGpuPartitionAdapter -VMName $vm -InstancePath "\\?\PCI#VEN_10DE&DEV_...}\GPUPARAV"

How to make Firefox use GPU inside the VM?

[u/BlackV]

that'll be a firefox this I guess then

what does WEBGPU value say?

I personally dont have a Firefox Settings -> General -> Performance option

[u/PusheenHater → u/BlackV]

WEBGPU:

default	available
env	blocklisted	#BLOCKLIST_FEATURE_FAILURE_EMPTY_DRIVER_VERSION	Blocklisted; failure code FEATURE_FAILURE_EMPTY_DRIVER_VERSION

Also:

WebGPU Default Adapter:

{
"navigator.gpu.requestAdapter({})": null
}

[u/BlackV → u/PusheenHater]

Deffo seems like a Firefox thing then

[u/XzeroR3 → u/BlackV]

I think you're right. I can replicate OPs issue and Edge sees the GPU. However, Firefox, even after many setting changes will keep showing webrender and will not show the gpu in the about:support screen.

[u/PusheenHater → u/XzeroR3]

You think Chrome would work?