diff --git a/doc/builders/packages/linux.section.md b/doc/builders/packages/linux.section.md
index b64da85791a0d95..151f4820d857520 100644
--- a/doc/builders/packages/linux.section.md
+++ b/doc/builders/packages/linux.section.md
@@ -39,3 +39,20 @@ How to add a new (major) version of the Linux kernel to Nixpkgs:
 4.  Test building the kernel: `nix-build -A linuxKernel.kernels.kernel_2_6_22`. If it compiles, ship it! For extra credit, try booting NixOS with it.
 
 5.  It may be that the new kernel requires updating the external kernel modules and kernel-dependent packages listed in the `linuxPackagesFor` function in `linux-kernels.nix` (such as the NVIDIA drivers, AUFS, etc.). If the updated packages aren’t backwards compatible with older kernels, you may need to keep the older versions around.
+
+## Manual kernel configs {#sec-manual-kernel-configs}
+
+Sometimes it may not be desirable to use the kernels already packaged in Nixpkgs, especially if most of the default configuration has to be altered or disabled to achieve a kernel as expected by the target use case. An example of this is building a kernel for use in a VM or micro VM. Nixpkgs provides the `linuxManualConfig` function for these cases: it requires the caller to pass the kernel sources and a config file, allowing one to build their own kernel with specific tuning.
+
+An example usage of `linuxManualConfig`:
+
+```nix
+{ pkgs, ... }: {
+  version = "X.Y.Z";
+  src = pkgs.fetchurl { ... };
+  configfile = ./path_to_config_file;
+  linux = pkgs.linuxManualConfig { inherit version src configfile; };
+}
+```
+
+Additional properties can be used with `linuxManualConfig` for further customisation. Readers who need more than the barebones example above should read [`pkgs/os-specific/linux/kernel/manual-config.nix`](https://github.com/NixOS/nixpkgs/blob/master/pkgs/os-specific/linux/kernel/manual-config.nix).