8 ms·

Looking Glass: Run a Windows VM on Linux in a Window with Native Performance

126 points by cercatrova 7y ago

cercatrova 7y ago
I saw a recent thread about running an X server on Windows for Linux applications, and this is sort of the opposite. You can run a Windows VM with GPU passthrough on a Linux host and if you want to run them side by side without switching windows, you can use a VNC window or other, but the problem is you don't get hardware acceleration. Looking Glass solves this by copying the Windows GPU frame buffer onto the Linux side so it can be read transparently. It's also open source. Source: https://github.com/gnif/LookingGlass https://github.com/gnif/LookingGlass Quickstart: https://looking-glass.hostfission.com/wiki/Installation https://looking-glass.hostfission.com/wiki/Installation Reddit discussion: https://old.reddit.com/r/vfio https://old.reddit.com/r/vfio This only works on a Linux host with Windows. There have been rumors that Apple might implement their own version for running perhaps a Windows VM or other VM transparently on a macOS host but those are just based on some virtIO development that seems to be going on in macOS. Or maybe it's to virtualize iOS or iPadOS, who knows? Personally I use Proxmox, which is a Linux hypervisor based on QEMU / KVM but with other features and a web GUI for administration, to run Windows, macOS, and Linux simultaneously, as well as host containers for side projects and other self hosted services.
- beagle3 7y ago
  What's your experience with running macOS under ProxMox? Do you have a guide for that you can point to?
  - cercatrova 7y ago
    Nick Sherlock has great guides: https://www.nicksherlock.com/2019/10/installing-macos-catalina-10-15-on-proxmox-6/ https://www.nicksherlock.com/2019/10/installing-macos-catali... I'd recommend trying to use OpenCore instead of Clover though. It's more stable even in a VM, and you don't need all the kexts as what the kexts are emulating for a bare metal machine are, in fact, emulated already as a VM. You can also check out /r/Hackintosh, they have some info on it.
- lostlogin 7y ago
  Thanks for this. > Personally I use Proxmox How do you find it to manage? With ESXi it’s quite easy to manage with Fusion, so I keep going back. Are you using the browser for Proxmox and Apple Remote Desktop/VNC to get into the machine?
  - cercatrova 7y ago
    Proxmox is very easy to manage, they have a web GUI. As for macOS, I either use VNC (NoMachine) or I switch the inputs on my monitor. I have each GPU hooked up to my monitor which has 4 display inputs. Then I have to use something like evdev or Barrier but it's usable.
    - lostlogin 7y ago
      Thanks - that way of passing through the graphics would never have occurred.
    - lazylizard 7y ago
      And pct can execute things inside containers so you can do everything from the host.
- Yetanfou 7y ago
  I use Proxmox on a server where it manages a herd of containers plus a few VMs for those times I need to run Windows. On a single DL380G7 Proxmox shepherds the following: Containers: - router (OpenWRT) - mail - web - media (serves audio, video, books, photos etc) - database - authentication, central letsencrypt instance - remote desktop/app session - build services - hydra (NSA's decompiler) - peer to peer apps - 'cloud' (Nextcloud) - comms (Jitsi meet, Nextcloud Talk + related services) VM: - Windows, several versions for experimenting - ELSA (VAG online service manual) All on a single box, easily managed through either the Proxmox web interface or - for those things which the web interface does not facilitate - through the CLI tools or by editing LXC or QEMU config files. While there are some areas where I have had to intervene to make things behave the way I want them to behave (e.g. I don't want to use ZFS since I prefer LVM raid so I had to set up storage 'by hand', the snapshot backup system does not cope with FUSE filesystems so I have to use hook scripts to unmount those before backup and remount them afterwards, etc) all in all the experience with Proxmox has been mostly positive.
  - beagle3 7y ago
    Impressive. Can you give a rough guideline about how much men and CPI you allocate to each task (and how much physical men and CPU are in the host)?
    - Yetanfou 7y ago
      I assume that by 'men' you mean 'cores'? If so, the host has two 6-core/12-thread CPU's (X5675@3.07GHz) and 128GB of memory, the internal array is populated with 8x146GB, the machine is hooked up to a NetApp DS4243 with 24x600GB (20 of which are in use, 4 cold spares). The machine has plenty of spare capacity, both CPU-wise as well as memory-wise. Storage is getting a bit short, eventually I'll start swapping drives in the DS4243 with higher-capacity versions. The whole contraption is housed in a sound-proofed cabinet with equipment in top, produce drying racks in the bottom. A forced draft fan all the way in the bottom of the rack draws in air through a large truck air filter in the top. This was the spare heat is used for a productive purpose instead of just wasted. Resources are used as needed, when a container seems to be running close to capacity I add cores, memory or storage. In the current configuration I assigned 2 cores/1GB to mail, 2 cores/1GB to auth, 8 cores/8GB to build, 6 cores/16GB to (data)base, 8 cores/16GB to serve (which runs a host of web services), 6 cores/8GB to session (which runs remote desktop/single app sessions through X2go), 4 cores/1GB to panopticon (CCTV), 2 cores/1GB to p2p, 4 cores/4GB to comms and 4 cores/512MB to router. Total load on the machine is negligible, memory pressure is... absent (currently ~8GB in use, ~84GB buffer/cache, ~36GB free). A machine like this one can be had for not that much ex-lease. As long as you get a G7 or newer power usage is acceptable, G6 and under are power hogs.
devit 7y ago
As far as I can tell you need two GPUs and all this does is efficiently copy the second GPU (assigned to a VM) output to a window on the main GPU (assigned to the host). This seems mostly useful for laptops with both integrated and discrete GPUs but no extra monitor output and for non-fullscreen 3D on desktops, since for fullscreen 3D on desktop you can just run a second cable to the monitor, which will be faster and allows the guest to drive monitor sync.
- serf 7y ago
  >This seems mostly useful for laptops with both integrated and discrete GPUs but no extra monitor output and for non-fullscreen 3D on desktops, since for fullscreen 3D on desktop you can just run a second cable to the monitor, which will be faster and allows the guest to drive monitor sync. i've been doing it for years (albeit with qemu), even with additional monitors available. It's nice to keep your workflow where you want it. I use a unix-alike OS nearly always, but work will inevitably pull me into a windows software that'll bitch about GPU acceleration (say.. autodesk fusion) even if it doesn't need it for the task. It's nice to keep that window where I want it. Sure, I loses sync/cec stuff, but I can drag that window across my entire workspace of monitors, and that's pretty powerful when you're stuck in a VM for a single piece of software. When I use a VM for gaming, that's when I run the GPU by itself to a separate monitor. Gaming VMs are ran weirdly anyway -- it'd probably have access to an entire block device rather than some VDI equivalent, PCI access, etc. That's more like just running two computers off of one mainboard at that point; not much to keep isolation sanitary.
  - NikolaeVarius 7y ago
    Can you play multiplayer games and not get banned?
    - Johnnynator 7y ago
      This depends on the Game, but most work and VM is usually not a reason to ban players. But some AntiCheat systems like the one from Valorant try to detect VM's and refuse to run on them.
DoofusOfDeath 7y ago
Slightly off-topic: I'm getting ready to build a new Linux gaming PC. I'm considering installing Windows 10 in a guest VM so I can run a few modern games that do poorly under Steam / Proton. Anyone suggestions for good sources of info regarding which software stacks (e.g., Ubuntu 19.10 + VMWare) are likely to provide a good experience? Graphics performance matters. I'm unwilling to run Windows 10 as the host OS because of personal feelings about telemetry.
- swebs 7y ago
  I haven't tried it myself, but there's a bit of info on the /g/ wiki with a hardware database linked at the bottom. https://wiki.installgentoo.com/index.php/PCI_passthrough https://wiki.installgentoo.com/index.php/PCI_passthrough
  - dehrmann 7y ago
    I've used PCI passthrough with VMWare ESXi. It's good when it works, but when it doesn't, you're out of luck. I doubt GP will have much luck with VMs once it gets to 3d acceleration.
    - deadbunny 7y ago
      GPU passthrough with qemu/kvm works spectacularly to 3D applications, I've been using it for years to play Windows only games from my linux desktop.
- pvik 7y ago
  My main desktop runs Linux, I do have a Windows VM (on qemu/libvirt) that I use primarily for Fusion360 and some gaming. I had to setup GPU passthrough with a second GPU for this. It is not that hard, you will however need to make sure your motherboard supports proper IOMMU grouping. This however, is the tricky part since most motherboard manufacturers do not really provide this information. [1] More info on ArchWiki: https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVM...
atum47 7y ago
I'll give this a try. On my last job I needed windows to run spark ar, Facebook's tool to create augmented reality for their Instagram filters. I was using vm ware, but it was glitchy
zelon88 7y ago
On a side note, this is an excellent landing page. My first thought when looking at the title was "I wonder if it does VGA pass-through." The second line of the landing page answered my question. Good job on the details so far! Can't wait to test it out.
jchw 7y ago
This works well for the most part. However, there are some things worth considering. For one, the frame relay program will need to start in your guest before Looking Glass can connect. Last I checked the best you can do is have it start at login, so you need autologin to have a somewhat seamless setup. Secondly, the cursor is sent through using the SPICE protocol, which is convenient. Unfortunately Looking Glass has no support for also handling audio, and no intent to merge such functionality in the future. So if you want audio, you’ll have to set up Qemu to forward audio directly to the host. Finally, GPU passthrough setups is the thing that sold me on NixOS. If you’re a fairly experienced Linux user, setting up this complicated and multifaceted setup in a mostly reproducible way using a single file of configuration is pretty pleasing. Most of my configuration was this: https://gist.github.com/jchv/b0e4b39679e450536a17cc6a5d69169a https://gist.github.com/jchv/b0e4b39679e450536a17cc6a5d69169... Really, all you need is to substitute the right IDs and it should practically work anywhere, all you have to do is setup a VM with the requirements met (UEFI, PCI-e device passthrough, Looking Glass device attached, and KVM FR server running) and run Looking Glass. Ultimately, I dropped Looking Glass and GPU passthrough. It was a little cumbersome and performance wasn’t perfect. I ran GPU passthrough on a physical monitor for a little while, and then dropped it entirely after finding out that Steam Proton and Wine actually covered all of my bases anyways.
- tbenst 7y ago
  Huh, cool! I’d love to run Illustrator/Photoshop on my NixOS box. I presume you use looking-glass-client from nixpkgs. Any other parts of the config you can share/recommend?
  - jchw 7y ago
    Not that I can recall! Yeah, I was using that one. In fact, when I wanted to upgrade, I actually submitted PRs to Nixpkgs for it. In the meantime, though, you can of course just use overlays or overrides to get a more up to date looking-glass-client in your local setup. Now, that does actually bring up at least one nice bit of configuration, which is how to configure your overlays to be consistent system-wide. It's covered on the wiki. I'll be honest, I still find overlays a little bit confusing, but I eventually got this setup working. It has a lot of advantages over other methods, my favorite of which is that all of my overlay stuff is consistent across the machine and stored in my Git-versioned NixOS configuration. You might already have this, but it's worth noting. https://nixos.wiki/wiki/Overlays#Using_nixpkgs.overlays_from_configuration.nix_as_.3Cnixpkgs-overlays.3E_in_your_NIX_PATH https://nixos.wiki/wiki/Overlays#Using_nixpkgs.overlays_from... Other than that and setting up the libvirt box, there wasn't really much else to it. I had it done in an hour or two. Pretty sure the only other NixOS configuration I had was setting my user to be in the `libvirtd` group.
bootloop 7y ago
If you are just running full-screen applications (like games or software) and you have multiple screens it is better to just use scripts to switch display inputs (via dcc). I wasn't really able to find a usecase for looking glass. (But it's an interesting idea.)
- cercatrova 7y ago
  You can also use evdev or Barrier.
LambdaB 7y ago
Funny coincidence to have this article on the front page while fixing the last sentences in my blog post. This post might help some people in regard to audio passthrough with PulseAudio in QEMU/KVM, which had a lot of problems until recently. Check it out: https://bitkeks.eu/blog/2020/04/compile-qemu-42-on-debian-buster-fix-pulseaudio-kvm-libvirt.html https://bitkeks.eu/blog/2020/04/compile-qemu-42-on-debian-bu... Related Tweet: https://twitter.com/bitkeks/status/1251892611343880194 https://twitter.com/bitkeks/status/1251892611343880194

126 points by cercatrova 7y ago

I saw a recent thread about running an X server on Windows for Linux applications, and this is sort of the opposite. You can run a Windows VM with GPU passthrough on a Linux host and if you want to run them side by side without switching windows, you can use a VNC window or other, but the problem is you don't get hardware acceleration. Looking Glass solves this by copying the Windows GPU frame buffer onto the Linux side so it can be read transparently. It's also open source. Source: https://github.com/gnif/LookingGlass https://github.com/gnif/LookingGlass Quickstart: https://looking-glass.hostfission.com/wiki/Installation https://looking-glass.hostfission.com/wiki/Installation Reddit discussion: https://old.reddit.com/r/vfio https://old.reddit.com/r/vfio This only works on a Linux host with Windows. There have been rumors that Apple might implement their own version for running perhaps a Windows VM or other VM transparently on a macOS host but those are just based on some virtIO development that seems to be going on in macOS. Or maybe it's to virtualize iOS or iPadOS, who knows? Personally I use Proxmox, which is a Linux hypervisor based on QEMU / KVM but with other features and a web GUI for administration, to run Windows, macOS, and Linux simultaneously, as well as host containers for side projects and other self hosted services.

beagle3 7y ago
What's your experience with running macOS under ProxMox? Do you have a guide for that you can point to?
- cercatrova 7y ago
  Nick Sherlock has great guides: https://www.nicksherlock.com/2019/10/installing-macos-catalina-10-15-on-proxmox-6/ https://www.nicksherlock.com/2019/10/installing-macos-catali... I'd recommend trying to use OpenCore instead of Clover though. It's more stable even in a VM, and you don't need all the kexts as what the kexts are emulating for a bare metal machine are, in fact, emulated already as a VM. You can also check out /r/Hackintosh, they have some info on it.
lostlogin 7y ago
Thanks for this. > Personally I use Proxmox How do you find it to manage? With ESXi it’s quite easy to manage with Fusion, so I keep going back. Are you using the browser for Proxmox and Apple Remote Desktop/VNC to get into the machine?
- cercatrova 7y ago
  Proxmox is very easy to manage, they have a web GUI. As for macOS, I either use VNC (NoMachine) or I switch the inputs on my monitor. I have each GPU hooked up to my monitor which has 4 display inputs. Then I have to use something like evdev or Barrier but it's usable.
  - lostlogin 7y ago
    Thanks - that way of passing through the graphics would never have occurred.
  - lazylizard 7y ago
    And pct can execute things inside containers so you can do everything from the host.
Yetanfou 7y ago
I use Proxmox on a server where it manages a herd of containers plus a few VMs for those times I need to run Windows. On a single DL380G7 Proxmox shepherds the following: Containers: - router (OpenWRT) - mail - web - media (serves audio, video, books, photos etc) - database - authentication, central letsencrypt instance - remote desktop/app session - build services - hydra (NSA's decompiler) - peer to peer apps - 'cloud' (Nextcloud) - comms (Jitsi meet, Nextcloud Talk + related services) VM: - Windows, several versions for experimenting - ELSA (VAG online service manual) All on a single box, easily managed through either the Proxmox web interface or - for those things which the web interface does not facilitate - through the CLI tools or by editing LXC or QEMU config files. While there are some areas where I have had to intervene to make things behave the way I want them to behave (e.g. I don't want to use ZFS since I prefer LVM raid so I had to set up storage 'by hand', the snapshot backup system does not cope with FUSE filesystems so I have to use hook scripts to unmount those before backup and remount them afterwards, etc) all in all the experience with Proxmox has been mostly positive.
- beagle3 7y ago
  Impressive. Can you give a rough guideline about how much men and CPI you allocate to each task (and how much physical men and CPU are in the host)?
  - Yetanfou 7y ago
    I assume that by 'men' you mean 'cores'? If so, the host has two 6-core/12-thread CPU's (X5675@3.07GHz) and 128GB of memory, the internal array is populated with 8x146GB, the machine is hooked up to a NetApp DS4243 with 24x600GB (20 of which are in use, 4 cold spares). The machine has plenty of spare capacity, both CPU-wise as well as memory-wise. Storage is getting a bit short, eventually I'll start swapping drives in the DS4243 with higher-capacity versions. The whole contraption is housed in a sound-proofed cabinet with equipment in top, produce drying racks in the bottom. A forced draft fan all the way in the bottom of the rack draws in air through a large truck air filter in the top. This was the spare heat is used for a productive purpose instead of just wasted. Resources are used as needed, when a container seems to be running close to capacity I add cores, memory or storage. In the current configuration I assigned 2 cores/1GB to mail, 2 cores/1GB to auth, 8 cores/8GB to build, 6 cores/16GB to (data)base, 8 cores/16GB to serve (which runs a host of web services), 6 cores/8GB to session (which runs remote desktop/single app sessions through X2go), 4 cores/1GB to panopticon (CCTV), 2 cores/1GB to p2p, 4 cores/4GB to comms and 4 cores/512MB to router. Total load on the machine is negligible, memory pressure is... absent (currently ~8GB in use, ~84GB buffer/cache, ~36GB free). A machine like this one can be had for not that much ex-lease. As long as you get a G7 or newer power usage is acceptable, G6 and under are power hogs.

devit 7y ago

As far as I can tell you need two GPUs and all this does is efficiently copy the second GPU (assigned to a VM) output to a window on the main GPU (assigned to the host). This seems mostly useful for laptops with both integrated and discrete GPUs but no extra monitor output and for non-fullscreen 3D on desktops, since for fullscreen 3D on desktop you can just run a second cable to the monitor, which will be faster and allows the guest to drive monitor sync.

serf 7y ago
>This seems mostly useful for laptops with both integrated and discrete GPUs but no extra monitor output and for non-fullscreen 3D on desktops, since for fullscreen 3D on desktop you can just run a second cable to the monitor, which will be faster and allows the guest to drive monitor sync. i've been doing it for years (albeit with qemu), even with additional monitors available. It's nice to keep your workflow where you want it. I use a unix-alike OS nearly always, but work will inevitably pull me into a windows software that'll bitch about GPU acceleration (say.. autodesk fusion) even if it doesn't need it for the task. It's nice to keep that window where I want it. Sure, I loses sync/cec stuff, but I can drag that window across my entire workspace of monitors, and that's pretty powerful when you're stuck in a VM for a single piece of software. When I use a VM for gaming, that's when I run the GPU by itself to a separate monitor. Gaming VMs are ran weirdly anyway -- it'd probably have access to an entire block device rather than some VDI equivalent, PCI access, etc. That's more like just running two computers off of one mainboard at that point; not much to keep isolation sanitary.
- NikolaeVarius 7y ago
  Can you play multiplayer games and not get banned?
  - Johnnynator 7y ago
    This depends on the Game, but most work and VM is usually not a reason to ban players. But some AntiCheat systems like the one from Valorant try to detect VM's and refuse to run on them.

DoofusOfDeath 7y ago

Slightly off-topic: I'm getting ready to build a new Linux gaming PC. I'm considering installing Windows 10 in a guest VM so I can run a few modern games that do poorly under Steam / Proton. Anyone suggestions for good sources of info regarding which software stacks (e.g., Ubuntu 19.10 + VMWare) are likely to provide a good experience? Graphics performance matters. I'm unwilling to run Windows 10 as the host OS because of personal feelings about telemetry.

swebs 7y ago
I haven't tried it myself, but there's a bit of info on the /g/ wiki with a hardware database linked at the bottom. https://wiki.installgentoo.com/index.php/PCI_passthrough https://wiki.installgentoo.com/index.php/PCI_passthrough
- dehrmann 7y ago
  I've used PCI passthrough with VMWare ESXi. It's good when it works, but when it doesn't, you're out of luck. I doubt GP will have much luck with VMs once it gets to 3d acceleration.
  - deadbunny 7y ago
    GPU passthrough with qemu/kvm works spectacularly to 3D applications, I've been using it for years to play Windows only games from my linux desktop.
pvik 7y ago
My main desktop runs Linux, I do have a Windows VM (on qemu/libvirt) that I use primarily for Fusion360 and some gaming. I had to setup GPU passthrough with a second GPU for this. It is not that hard, you will however need to make sure your motherboard supports proper IOMMU grouping. This however, is the tricky part since most motherboard manufacturers do not really provide this information. [1] More info on ArchWiki: https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVMF https://wiki.archlinux.org/index.php/PCI_passthrough_via_OVM...

atum47 7y ago

I'll give this a try. On my last job I needed windows to run spark ar, Facebook's tool to create augmented reality for their Instagram filters. I was using vm ware, but it was glitchy

zelon88 7y ago

On a side note, this is an excellent landing page. My first thought when looking at the title was "I wonder if it does VGA pass-through." The second line of the landing page answered my question. Good job on the details so far! Can't wait to test it out.

jchw 7y ago

This works well for the most part. However, there are some things worth considering. For one, the frame relay program will need to start in your guest before Looking Glass can connect. Last I checked the best you can do is have it start at login, so you need autologin to have a somewhat seamless setup. Secondly, the cursor is sent through using the SPICE protocol, which is convenient. Unfortunately Looking Glass has no support for also handling audio, and no intent to merge such functionality in the future. So if you want audio, you’ll have to set up Qemu to forward audio directly to the host. Finally, GPU passthrough setups is the thing that sold me on NixOS. If you’re a fairly experienced Linux user, setting up this complicated and multifaceted setup in a mostly reproducible way using a single file of configuration is pretty pleasing. Most of my configuration was this: https://gist.github.com/jchv/b0e4b39679e450536a17cc6a5d69169a https://gist.github.com/jchv/b0e4b39679e450536a17cc6a5d69169... Really, all you need is to substitute the right IDs and it should practically work anywhere, all you have to do is setup a VM with the requirements met (UEFI, PCI-e device passthrough, Looking Glass device attached, and KVM FR server running) and run Looking Glass. Ultimately, I dropped Looking Glass and GPU passthrough. It was a little cumbersome and performance wasn’t perfect. I ran GPU passthrough on a physical monitor for a little while, and then dropped it entirely after finding out that Steam Proton and Wine actually covered all of my bases anyways.

tbenst 7y ago
Huh, cool! I’d love to run Illustrator/Photoshop on my NixOS box. I presume you use looking-glass-client from nixpkgs. Any other parts of the config you can share/recommend?
- jchw 7y ago
  Not that I can recall! Yeah, I was using that one. In fact, when I wanted to upgrade, I actually submitted PRs to Nixpkgs for it. In the meantime, though, you can of course just use overlays or overrides to get a more up to date looking-glass-client in your local setup. Now, that does actually bring up at least one nice bit of configuration, which is how to configure your overlays to be consistent system-wide. It's covered on the wiki. I'll be honest, I still find overlays a little bit confusing, but I eventually got this setup working. It has a lot of advantages over other methods, my favorite of which is that all of my overlay stuff is consistent across the machine and stored in my Git-versioned NixOS configuration. You might already have this, but it's worth noting. https://nixos.wiki/wiki/Overlays#Using_nixpkgs.overlays_from_configuration.nix_as_.3Cnixpkgs-overlays.3E_in_your_NIX_PATH https://nixos.wiki/wiki/Overlays#Using_nixpkgs.overlays_from... Other than that and setting up the libvirt box, there wasn't really much else to it. I had it done in an hour or two. Pretty sure the only other NixOS configuration I had was setting my user to be in the `libvirtd` group.

bootloop 7y ago

If you are just running full-screen applications (like games or software) and you have multiple screens it is better to just use scripts to switch display inputs (via dcc). I wasn't really able to find a usecase for looking glass. (But it's an interesting idea.)

cercatrova 7y ago
You can also use evdev or Barrier.

LambdaB 7y ago

Funny coincidence to have this article on the front page while fixing the last sentences in my blog post. This post might help some people in regard to audio passthrough with PulseAudio in QEMU/KVM, which had a lot of problems until recently. Check it out: https://bitkeks.eu/blog/2020/04/compile-qemu-42-on-debian-buster-fix-pulseaudio-kvm-libvirt.html https://bitkeks.eu/blog/2020/04/compile-qemu-42-on-debian-bu... Related Tweet: https://twitter.com/bitkeks/status/1251892611343880194 https://twitter.com/bitkeks/status/1251892611343880194