VirGL Driver Works, But Cannot Set VRAM Greater than 512 MiB

[SInisterPisces]

Hello,

I'm on the latest PVE, version 7.3-3. I just updated today.

My integrated GPU (Ryzen 5900HX: Cezanne-based hardware) has 16 GiB of system RAM allocated to it.

When I set up a VM with a VirGL Display, the GUI won't let me specify a VRAM value greater than 512 MB. It puts a red box around the entry field and refuses to allow me to specify anything greater than that.

I edited the VM config file directly.

root@andromeda-ii:/etc/pve/qemu-server# cat 2500.conf
agent: 1,fstrim_cloned_disks=1
audio0: device=ich9-intel-hda,driver=spice
bios: ovmf
boot: order=scsi0;net0
cores: 4
cpu: host
efidisk0: vmStore:vm-2500-disk-0,efitype=4m,pre-enrolled-keys=1,size=1M
machine: q35
memory: 6144
meta: creation-qemu=7.1.0,ctime=1671926505
name: DragonOS-A2
net0: virtio=E6:3F:C4:08:2C:3D,bridge=vmbr0
numa: 0
ostype: l26
scsi0: vmDisks64k:vm-2500-disk-0,discard=on,iothread=1,size=64G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=878d3834-6567-4e31-90fe-4bc5dfc4400c
sockets: 1
spice_enhancements: videostreaming=all
usb0: host=03eb:800c
vga: virtio-gl,memory=4096
vmgenid: 89a36cdd-d4c3-4fb8-bbb0-737f5823a91c

The GUI did not like that. Now it thinks it has the Default display driver again. In fact, it's acting like it has the default driver active, as I can't use SPICE anymore.

I assume I either (1) need to add something more to the VM config file; or (2) remove some sort of limiter setting from PVE? Is there actually anything I can do to fix this?

EDIT: Fixing it in the GUI (setting it to VirGL again) just overwrites the line where I set the custom GPU RAM value to whatever's set in the GUI.

 

[cheiss]

Looking at the code, the limit of 512 MiB is indeed just a hardcoded "limitation", on both sides.
This was just set as a reasonable upper limit back then, if I had to guess.

Best thing would be to create a ticket over at https://bugzilla.proxmox.com/, so that this will be fixed in the future.
Before raising it, it should be figured out what the new maximum should be or what heuristic to use for calculating it dynamically.

 

[SInisterPisces]

Looking at the code, the limit of 512 MiB is indeed just a hardcoded "limitation", on both sides.
This was just set as a reasonable upper limit back then, if I had to guess.

Best thing would be to create a ticket over at https://bugzilla.proxmox.com/, so that this will be fixed in the future.
Before raising it, it should be figured out what the new maximum should be or what heuristic to use for calculating it dynamically.

Thanks! I wouldn't have known where to start looking for it in the source.

I reported it here: https://bugzilla.proxmox.com/show_bug.cgi?id=4463

 

[SInisterPisces]

Can anyone confirm if this bug still exists in Proxmox 8? I don't have a node with a GPU right now to test.

 

[eth]

Can anyone confirm if this bug still exists in Proxmox 8? I don't have a node with a GPU right now to test.

still exists in 8.1.3

 

[Kav91]

Yep I'm on 8.1.3 and experiencing the same also. Would really like to dial this up.

There is also another problem with Spice where it doesn't work with anything over 128MB that I hit also.
https://forum.proxmox.com/threads/guest-has-not-initialized-display-yet.118883/ .