nixos/docs: document new qemu-vm features

nixos/doc/manual/from_md/release-notes/rl-2111.section.xml

@@ -1020,6 +1020,40 @@ Superuser created successfully.
           <literal>linuxPackages_latest</literal>) remain untouched.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          In NixOS virtual machines (QEMU), the
+          <literal>virtualisation</literal> module has been updated with
+          new options to configure:
+        </para>
+        <itemizedlist spacing="compact">
+          <listitem>
+            <para>
+              IPv4 port forwarding
+              (<link xlink:href="options.html#opt-virtualisation.forwardPorts"><literal>virtualisation.forwardPorts</literal></link>),
+            </para>
+          </listitem>
+          <listitem>
+            <para>
+              shared host directories
+              (<link xlink:href="options.html#opt-virtualisation.sharedDirectories"><literal>virtualisation.sharedDirectories</literal></link>),
+            </para>
+          </listitem>
+          <listitem>
+            <para>
+              screen resolution
+              (<link xlink:href="options.html#opt-virtualisation.resolution"><literal>virtualisation.resolution</literal></link>).
+            </para>
+          </listitem>
+        </itemizedlist>
+        <para>
+          In addition, the default
+          <link xlink:href="options.html#opt-virtualisation.msize"><literal>msize</literal></link>
+          parameter in 9P filesystems (including /nix/store and all
+          shared directories) has been increased to 16K for improved
+          performance.
+        </para>
+      </listitem>
       <listitem>
         <para>
           The setting

nixos/doc/manual/release-notes/rl-2111.section.md

@@ -310,9 +310,17 @@ To be able to access the web UI this port needs to be opened in the firewall.
 
 ## Other Notable Changes {#sec-release-21.11-notable-changes}
 
+
 - The linux kernel package infrastructure was moved out of `all-packages.nix`, and restructured. Linux related functions and attributes now live under the `pkgs.linuxKernel` attribute set.
   In particular the versioned `linuxPackages_*` package sets (such as `linuxPackages_5_4`) and kernels from `pkgs` were moved there and now live under `pkgs.linuxKernel.packages.*`. The unversioned ones (such as `linuxPackages_latest`) remain untouched.
 
+- In NixOS virtual machines (QEMU), the `virtualisation` module has been updated with new options to configure:
+    - IPv4 port forwarding ([`virtualisation.forwardPorts`](options.html#opt-virtualisation.forwardPorts)),
+    - shared host directories ([`virtualisation.sharedDirectories`](options.html#opt-virtualisation.sharedDirectories)),
+    - screen resolution ([`virtualisation.resolution`](options.html#opt-virtualisation.resolution)).
+
+  In addition, the default [`msize`](options.html#opt-virtualisation.msize) parameter in 9P filesystems (including /nix/store and all shared directories) has been increased to 16K for improved performance.
+
 - The setting [`services.openssh.logLevel`](options.html#opt-services.openssh.logLevel) `"VERBOSE"` `"INFO"`. This brings NixOS in line with upstream and other Linux distributions, and reduces log spam on servers due to bruteforcing botnets.
 
   However, if [`services.fail2ban.enable`](options.html#opt-services.fail2ban.enable) is `true`, the `fail2ban` will override the verbosity to `"VERBOSE"`, so that `fail2ban` can observe the failed login attempts from the SSH logs.