Add nvidia GPU Pre Init command

README.md

@@ -17,7 +17,7 @@ TrueNAS SCALE already has everything onboard to create persistent Linux 'jails'
 - Setting up the jail so it won't be lost when you update SCALE
 - Choosing a distro (Debian 11 strongly recommended, but Ubuntu, Arch Linux or Rocky Linux seem good choices too)
 - Optional: configuring the jail so you can run Docker inside it
-- Optional: GPU passthrough (including nvidia GPU with the drivers bind mounted from the host)
+- Optional: GPU passthrough (including [nvidia GPU](README.md#nvidia-gpu) with the drivers bind mounted from the host)
 - Starting the jail with your config applied
 
 ## Installation
@@ -114,6 +114,16 @@ See [Advanced Networking](./NETWORKING.md) for more.
 
 Jailmaker won't install Docker for you, but it can setup the jail with the capabilities required to run docker. You can manually install Docker inside the jail using the [official installation guide](https://docs.docker.com/engine/install/#server) or use [convenience script](https://get.docker.com).
 
+## Nvidia GPU
+
+To make passthrough of the nvidia GPU work, you need to schedule a Pre Init command. The reason is that TrueNAS SCALE by default doesn't load the nvidia kernel modules (and jailmaker doesn't do that either).
+
+```
+[ ! -f /dev/nvidia-uvm ] && modprobe nvidia-current-uvm && /usr/bin/nvidia-modprobe -c0 -u
+```
+
+![Pre Init config screenshot](https://user-images.githubusercontent.com/1704047/222915803-d6dd51b0-c4dd-4189-84be-a04d38cca0b3.png)
+
 ## Comparison
 
 TODO: write comparison between systemd-nspawn (without jailmaker), LXC, VMs, Docker (on the host).