Looking Glass B7

https://looking-glass.io/docs/B7/
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Looking Glass is an open-source application that enables the use of a KVM with VGA PCI Pass-through...
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### Install OBS plugin for all users with sudo

Source: https://looking-glass.io/docs/B7/obs/

Run sudo make install when installing for all users.

```bash
sudo make install
```

--------------------------------

### Install client system-wide with make install

Source: https://looking-glass.io/docs/B7/install_client/

Run as root to install the built Looking Glass client system-wide. Requires building the client from source first.

```bash
make install
```

--------------------------------

### Build OBS plugin for user install

Source: https://looking-glass.io/docs/B7/obs/

Build the plugin with USER_INSTALL=1 to install for the current user.

```bash
mkdir obs/build
cd obs/build
cmake -DUSER_INSTALL=1 ../
make
```

--------------------------------

### Install build dependencies with apt-get

Source: https://looking-glass.io/docs/B7/build/

Installs all required and optional dependencies for building the Looking Glass client on Debian. Adjust the list based on whether you use PipeWire or PulseAudio; installing PipeWire libraries on a PulseAudio system results in a broken partial install.

```bash
apt-get install binutils-dev cmake fonts-dejavu-core libfontconfig-dev \
gcc g++ pkg-config libegl-dev libgl-dev libgles-dev libspice-protocol-dev \
nettle-dev libx11-dev libxcursor-dev libxi-dev libxinerama-dev \
libxpresent-dev libxss-dev libxkbcommon-dev libwayland-dev wayland-protocols \
libpipewire-0.3-dev libpulse-dev libsamplerate0-dev
```

--------------------------------

### Install client for local user with cmake prefix

Source: https://looking-glass.io/docs/B7/install_client/

Installs the client only for the current user by setting the install prefix to ~/.local. Run from the build directory after configuring with cmake.

```bash
cmake -DCMAKE_INSTALL_PREFIX=~/.local .. && make install
```

--------------------------------

### Example INI configuration file

Source: https://looking-glass.io/docs/B7/usage/

Shows the INI format used by Looking Glass config files. The example sets fullScreen=yes under [win], nvGain=1 under [egl], and includes a comment. Config files are loaded in order from /etc/looking-glass-client.ini, ~/.looking-glass-client.ini, and $XDG_CONFIG_HOME/looking-glass/client.ini, with later files overriding earlier ones. Command line arguments override config file options.

```ini
[win]
fullScreen=yes

[egl]
nvGain=1

; this is a comment
```

--------------------------------

### Install libobs-dev with apt-get

Source: https://looking-glass.io/docs/B7/obs/

Install the required libobs-dev package using apt-get.

```bash
apt-get install libobs-dev
```

--------------------------------

### Build Windows installer with makensis

Source: https://looking-glass.io/docs/B7/build/

Runs makensis on installer.nsi from the host/build/platform/Windows directory. Produces looking-glass-host-setup.exe in the same directory.

```bash
cd host/build/platform/Windows
makensis installer.nsi
```

--------------------------------

### Install NSIS on Linux

Source: https://looking-glass.io/docs/B7/build/

Installs the NSIS package via apt-get, required for building the Windows installer.

```bash
apt-get install nsis
```

--------------------------------

### Build OBS plugin for all users

Source: https://looking-glass.io/docs/B7/obs/

Build the plugin without USER_INSTALL to install for all users.

```bash
mkdir obs/build
cd obs/build
cmake ../
make
```

--------------------------------

### QEMU command-line options for SPICE guest agent

Source: https://looking-glass.io/docs/B7/install_libvirt/

Use these QEMU command-line options to enable the SPICE guest agent for clipboard synchronization. Install the SPICE guest tools from spice-space.org first.

```bash
-device virtio-serial-pci \
-chardev spicevmc,id=vdagent,name=vdagent \
-device virtserialport,chardev=vdagent,name=com.redhat.spice.0
```

--------------------------------

### Install Looking Glass service manually

Source: https://looking-glass.io/docs/B7/faq/

Run this command to install the Looking Glass service manually. This allows the host to run as the SYSTEM user, enabling high-priority GPU capture and secure desktop capture.

```text
looking-glass-host.exe InstallService
```

--------------------------------

### Install Linux headers and DKMS

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Install the required Linux kernel headers and DKMS to build and manage the KVMFR module.

```bash
apt-get install linux-headers-$(uname -r) dkms
```

--------------------------------

### Downsampling configuration examples

Source: https://looking-glass.io/docs/B7/usage/

Three downsample configuration examples: exact downsample of 3840x2160 to 1920x1080, downsample anything greater than 1920x1080 to 1920x1080, and a comma-separated list of two rules for different source resolutions.

```ini
; Downsample exactly 3840x2160 to 1920x1080
downsample=3840x2160:1920x1080

; Downsample anything greater then 1920x1080 to 1920x1080
downsample=>1920x1080:1920x1080

; Downsample 3840x2160 to 1920x1080, or 3840x2400 to 1920x1200
downsample=3840x2160:1920x1080,3840x2400:1920x1200
```

--------------------------------

### Install MSYS2 build dependencies with pacman

Source: https://looking-glass.io/docs/B7/build/

Run these commands in the MSYS2 shell to download build dependencies for the Windows host build. Installs git, make, mingw-w64-x86_64-gcc, and mingw-w64-x86_64-cmake.

```bash
pacman -Fy
pacman -Sy git make mingw-w64-x86_64-gcc mingw-w64-x86_64-cmake
```

--------------------------------

### IVSHMEM device listing from looking-glass-host.txt log

Source: https://looking-glass.io/docs/B7/usage/

Example log output showing IVSHMEM devices with their bus/device/function addresses. The asterisk (*) marks the currently selected device.

```log
[I]     19989544      …      IVSHMEM 0  on bus 0x6, device 0x3, function 0x0
[I]     19990438      …      IVSHMEM 1* on bus 0x6, device 0x5, function 0x0
```

--------------------------------

### Configure os:shmDevice to select the second IVSHMEM device

Source: https://looking-glass.io/docs/B7/usage/

Sets the shmDevice option to 1 in the [os] section, selecting the second IVSHMEM device (ordered by PCI slot, starting from 0). The option ignores actual PCI slot numbers and uses the Nth slot occupied by an IVSHMEM device.

```ini
[os]
; Select the second IVSHMEM device
shmDevice=1
```

--------------------------------

### Build the client with cmake and make

Source: https://looking-glass.io/docs/B7/build/

Creates a build directory, configures with cmake, and compiles the client. Produces the looking-glass-client binary.

```bash
mkdir client/build
cd client/build
cmake ../
make
```

--------------------------------

### Install KVMFR module into DKMS

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Install the KVMFR module into DKMS using the dkms install command.

```bash
dkms install "."
```

--------------------------------

### looking-glass-client --help

Source: https://looking-glass.io/docs/B7/usage/

Displays a full list of command line options. Use -h as a short alias.

```text
looking-glass-client --help
```

--------------------------------

### Run the client from the build directory

Source: https://looking-glass.io/docs/B7/build/

Runs the built looking-glass-client binary directly from the build directory.

```bash
./looking-glass-client
```

--------------------------------

### Configure and build host on Linux

Source: https://looking-glass.io/docs/B7/build/

Creates the host/build directory, configures the project with CMake, and builds with make. Run from the source tree root.

```bash
mkdir host/build
cd host/build
cmake ..
make
```

--------------------------------

### QEMU commandline block for legacy syntax (QEMU <6.2 or libvirt <7.9)

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Use this legacy XML block for older QEMU/libvirt versions. Using it on newer versions may cause QEMU to abort with a PCI slot error.

```xml
<qemu:commandline>
  <qemu:arg value="-device"/>
  <qemu:arg value="ivshmem-plain,id=shmem0,memdev=looking-glass"/>
  <qemu:arg value="-object"/>
  <qemu:arg value="memory-backend-file,id=looking-glass,mem-path=/dev/kvmfr0,size=32M,share=yes"/>
</qemu:commandline>
```

--------------------------------

### QEMU command line arguments for direct QEMU usage

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Add these arguments to your QEMU command line when not using libvirt. The 'size' must match the static_size_mb used when loading the kernel module.

```bash
-device ivshmem-plain,id=shmem0,memdev=looking-glass
-object memory-backend-file,id=looking-glass,mem-path=/dev/kvmfr0,size=32M,share=yes
```

--------------------------------

### Load KVMFR module with static_size_mb

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Load the KVMFR module with the static_size_mb parameter, using the value calculated as per the Determining Memory guide.

```bash
modprobe kvmfr static_size_mb=32
```

--------------------------------

### Configure and build host on Windows (MSYS2)

Source: https://looking-glass.io/docs/B7/build/

Creates the host/build directory, configures the project with CMake using the 'MSYS Makefiles' generator, and builds with make. Run from the source tree root.

```bash
mkdir host/build
cd host/build
cmake -G "MSYS Makefiles" ..
make
```

--------------------------------

### Service log file path

Source: https://looking-glass.io/docs/B7/faq/

The log file for the Looking Glass service is located at this path. Useful for troubleshooting errors related to the host application not starting.

```text
%ProgramData%\Looking Glass (host)\looking-glass-host-service.txt
```

--------------------------------

### Load KVMFR module at boot with systemd-modules-load

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Create /etc/modules-load.d/kvmfr.conf to load the KVMFR module automatically at system startup.

```bash
# KVMFR Looking Glass module
kvmfr
```

--------------------------------

### QEMU commandline block for JSON syntax (QEMU 6.2+ and libvirt 7.9+)

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Use this XML block for QEMU 6.2 or later and libvirt 7.9 or later. The 'size' value is in bytes; calculate as size_in_MB x 1024 x 1024.

```xml
<qemu:commandline>
  <qemu:arg value="-device"/>
  <qemu:arg value="{'driver':'ivshmem-plain','id':'shmem0','memdev':'looking-glass'}"/>
  <qemu:arg value="-object"/>
  <qemu:arg value="{'qom-type':'memory-backend-file','id':'looking-glass','mem-path':'/dev/kvmfr0','size':33554432,'share':true}"/>
</qemu:commandline>
```

--------------------------------

### Disable VirtIO memballoon device

Source: https://looking-glass.io/docs/B7/install_libvirt/

Set the memballoon model to 'none' to disable the device, which causes major performance issues with VFIO passthrough setups. Find the <memballoon> tag in your libvirt XML and replace it with this.

```xml
<memballoon model="none"/>
```

--------------------------------

### looking-glass-client -f /dev/shm/my-lg-shmem (short with parameter)

Source: https://looking-glass.io/docs/B7/usage/

Uses the specified shared memory file with the short option -f.

```text
looking-glass-client -f /dev/shm/my-lg-shmem
```

--------------------------------

### Cross-compile Windows host on Linux with mingw64

Source: https://looking-glass.io/docs/B7/build/

Like the Linux build, but uses the mingw64 toolchain file to cross-compile a Windows .exe. Run from the source tree root.

```bash
mkdir host/build
cd host/build
cmake -DCMAKE_TOOLCHAIN_FILE=../toolchain-mingw64.cmake ..
make
```

--------------------------------

### looking-glass-client app:shmFile=/dev/shm/my-lg-shmem (long with parameter)

Source: https://looking-glass.io/docs/B7/usage/

Uses the specified shared memory file with the long option app:shmFile.

```text
looking-glass-client app:shmFile=/dev/shm/my-lg-shmem
```

--------------------------------

### systemd-tmpfiles configuration for shared memory permissions

Source: https://looking-glass.io/docs/B7/ivshmem_shm/

Create /etc/tmpfiles.d/10-looking-glass.conf with this content to pre-create /dev/shm/looking-glass with proper permissions. Change 'user' to the username that will run Looking Glass. The file must be owned by that user and group 'kvm' with mode 0660.

```conf
# Type Path               Mode UID  GID Age Argument

f /dev/shm/looking-glass 0660 user kvm -
```

--------------------------------

### QEMU command-line arguments for IVSHMEM

Source: https://looking-glass.io/docs/B7/ivshmem_shm/

Use these arguments when running QEMU directly without libvirt. Adjust the 'bus' parameter to match your configuration. The memory size (32M) may need adjustment per the 'Determining memory' section.

```bash
-device ivshmem-plain,memdev=ivshmem,bus=pcie.0 \
-object memory-backend-file,id=ivshmem,share=on,mem-path=/dev/shm/looking-glass,size=32M
```

--------------------------------

### Restart libvirtd after cgroups change

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Run this command to restart libvirtd after editing /etc/libvirt/qemu.conf to include /dev/kvmfr0 in the cgroup_device_acl block.

```bash
sudo systemctl restart libvirtd.service
```

--------------------------------

### AppArmor profile for /dev/kvmfr0

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Add this line to /etc/apparmor.d/local/abstractions/libvirt-qemu to allow access to /dev/kvmfr0. Required to avoid AppArmor blocking the VM.

```apparmor
# Looking Glass
/dev/kvmfr0 rw,
```

--------------------------------

### Create udev rule for KVMFR permissions

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Create /etc/udev/rules.d/99-kvmfr.rules with this content to set ownership and permissions for the kvmfr device.

```bash
SUBSYSTEM=="kvmfr", OWNER="user", GROUP="kvm", MODE="0660"
```

--------------------------------

### looking-glass-client -F (short)

Source: https://looking-glass.io/docs/B7/usage/

Automatically enters full screen using the short option -F.

```text
looking-glass-client -F
```

--------------------------------

### Make static_size_mb permanent via modprobe.d

Source: https://looking-glass.io/docs/B7/ivshmem_kvmfr/

Create /etc/modprobe.d/kvmfr.conf with the options line to set static_size_mb permanently.

```bash
options kvmfr static_size_mb=32
```

--------------------------------

### Enable NvFBC capture in looking-glass-host.ini

Source: https://looking-glass.io/docs/B7/faq/

Add this configuration to the host ini file at `%ProgramFiles%\Looking Glass (host)\looking-glass-host.ini` to enable NvFBC capture. Create the file if it doesn't exist. NvFBC is only supported on professional-grade GPUs.

```ini
[app]
capture=nvfbc
```

--------------------------------

### AppArmor permission for shared memory file

Source: https://looking-glass.io/docs/B7/install_libvirt/

Add this line to /etc/apparmor.d/local/abstractions/libvirt-qemu to allow QEMU to access the shared memory file. Required for libvirt versions before 5.10.0 when using AppArmor.

```text
/dev/shm/looking-glass rw,
```

--------------------------------

### libvirt XML channel configuration for SPICE guest agent

Source: https://looking-glass.io/docs/B7/install_libvirt/

Add this channel configuration to your libvirt VM XML to enable the SPICE guest agent. The VirtIO Serial device is added automatically, so no need to add it manually.

```xml
<channel type="spicevmc">
  <target type="virtio" name="com.redhat.spice.0"/>
  <address type="virtio-serial" controller="0" bus="0" port="1"/>
</channel>
<!-- No need to add a VirtIO Serial device, it will be added automatically -->
```

--------------------------------

### Host log file path

Source: https://looking-glass.io/docs/B7/faq/

The log file for the host application is located at this path. You can also open it by right-clicking the system tray icon and selecting 'Open Log File'.

```text
%ProgramData%\Looking Glass (host)\looking-glass-host.txt
```
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