5 ms·
You don't need this for general productivity software, only stuff where QEMU's emulated GPU is too slow or otherwise insufficient (so games, video editing, etc)
by Nullabillity 5y ago
You don't need this for general productivity software, only stuff where QEMU's emulated GPU is too slow or otherwise insufficient (so games, video editing, etc).
The caveats are basically:
1. Setup is a bit annoying
LG can feed input into any VM but requires guest support for capture, so you need to do the setup with a direct monitor.
2. The passed-through card must have a monitor connected.
IIRC, this is an API issue since it just captures what would go to that monitor.
3. Some things are only visible on the real monitor.
They need different capture strategies for the regular desktop, system desktops (such as lock screens), and secure desktops (UAC prompts). Sometimes the transition fails, sometimes there is no strategy implemented for what you're trying to show.
4. Your CPU and motherboard must support IOMMU passthrough.
For Intel this means using Skylake+ and ensuring that it supports VT-d. For AMD this means using Ryzen with an X-series motherboard.
5. You need separate GPUs for the host and guest.
Blame GPU vendors for making VT-g an enterprise-only feature.
- gnif 5y ago1. We are working on it 2. Not if it's a vGPU or a Quadro where EDID spoofing is allowed 3. No, we capture everything now, even the windows Login screen and windows updates, etc. 4. Yes 5. Very yes!
- Nullabillity 5y ago> 3. No, we capture everything now, even the windows Login screen and windows updates, etc. B3 and B4 both have pretty huge improvements here, but there are still a few rough corners. For example, when logging out the host shuts down immediately upon request, so you can't see the "program X is blocking shutdown" dialog. But ultimately this is a very minor papercut for a very impressive and useful project.
- gnif 5y agoReally? I see this all the time with my VM when I shutdown via LG.
- Nullabillity 5y agoHuh, so this is a bit more involved than I thought. I just tried again to confirm (still on B4). The first time I tried I just got the Looking Glass splash as soon as I clicked shut down. When I cancelled that and tried again I was able to see both the throbber and the prompt. When I let the VM sit idle for a while before trying again, the LG splash was back. Rebooting the VM also seems to bring back the splash reliably.
- carlhjerpe 5y agoCreate a desktop shortcut to "shutdown -s -t 1" it'll keep shutting down even if an application might try to keep the system running.
- sm_ts 5y ago> 2. The passed-through card must have a monitor connected. Regarding this, I don't know about LG, but with a standard QEMU VFIO setup, one use a single monitor connected to the two cards, and switch the input when required.
- gnif 5y agoYup, this is a good option too, makes it easy to debug/diagnose when things go wrong with the guest VM too. Just note that not all multi-input monitors are equal though, a small minority appear to the GPU as unplugged when the input selection is changed.