Rename External subsections to avoid name collision

QubesOS/qubes-issues#4693

external/os-guides/linux-hvm-tips.md

@@ -0,0 +1,96 @@
+---
+layout: doc
+title: Linux HVM Tips
+permalink: /doc/linux-hvm-tips/
+redirect_from:
+- /en/doc/linux-hvm-tips/
+- /doc/LinuxHVMTips/
+- /wiki/LinuxHVMTips/
+---
+
+Tips for Linux in HVM domain
+============================
+
+How to fix bootup kernel error 
+-------------------------------
+
+The HVM may pause on boot, showing a fixed cursor.
+After a while a series of warnings may be shown similar to this:
+
+    BUG: soft lockup - CPU#0 stuck for 23s! [systemd-udevd:244]
+
+To fix this:
+
+1.  Kill the HVM.
+1.  Start the HVM
+1.  Press "e" at the grub screen to edit the boot parameters
+1.  Find the /vmlinuz line, and edit it to replace "rhgb" with "modprobe.blacklist=bochs_drm"
+1.  Press "Ctrl-x" to start the HVM
+
+If this solves the problem then you will want to make the change permanent:
+
+1.  Edit the file `/etc/default/grub`.
+1.  Find the line which starts:
+    ~~~
+    GRUB_CMDLINE_LINUX=
+    ~~~
+1.  Remove this text from that line:
+    ~~~
+    rhgb
+    ~~~
+1.  Add this text to that line:
+    ~~~
+    modprobe.blacklist=bochs_drm
+    ~~~
+1.  Run this command:
+    ~~~
+    grub2-mkconfig --output=/boot/grub2/grub.cfg
+    ~~~
+
+The HVM should now start normally.
+
+
+Screen resolution
+-----------------
+
+Some kernel/Xorg combinations use only 640x480 in HVM, which is quite small. 
+To enable maximum resolution, some changes in the Xorg configuration are needed:
+1.  Force "vesa" video driver
+2.  Provide wide horizontal synchronization range
+
+To achieve it (all commands to be run as root):
+
+1.  Generate XOrg configuration (if you don't have it):
+    ~~~
+    X -configure :1 && mv ~/xorg.conf.new /etc/X11/xorg.conf
+    ~~~
+
+1.  Add HorizSync line to Monitor section, it should look something like:
+    ~~~
+    Section "Monitor"
+            Identifier   "Monitor0"
+            VendorName   "Monitor Vendor"
+            ModelName    "Monitor Model"
+            HorizSync    30.0 - 60.0
+    EndSection
+    ~~~
+
+1.  Change driver to "vesa" in Device section:
+    ~~~
+    Section "Device"
+            # (...)
+            Identifier  "Card0"
+            Driver      "vesa"
+            VendorName  "Technical Corp."
+            BoardName   "Unknown Board"
+            BusID       "PCI:0:2:0"
+    EndSection
+    ~~~
+
+Now you should get resolution of at least 1280x1024 and should be able to choose other modes.
+
+Qubes agents
+------------
+
+Linux Qubes agents are written primarily for PV qubes, but it is possible to run them also in a HVM qube.
+However some work may be required to achieve this. Check [this thread](https://groups.google.com/group/qubes-devel/browse_thread/thread/081df4a43e49e7a5).