Add HVM Troubleshooting

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

@@ -14,41 +14,7 @@ Tips for Linux in HVM domain
 How to fix bootup kernel error 
 -------------------------------
 
-The HVM may pause on boot, showing a fixed cursor.
+If the HVM pauses on boot and shows a series of warnings, visit [HVM Troubleshooting](/doc/hvm-troubleshooting/#hvm-pauses-on-boot-followed-by-kernel-error) for a fix. 
-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
 -----------------

user/troubleshooting/hvm-troubleshooting.md

@@ -0,0 +1,64 @@
+---
+layout: doc
+title: HVM Troubleshooting
+permalink: /doc/hvm-troubleshooting/
+redirect_from:
+- /en/doc/wireless-troubleshooting/
+- /doc/wireless-troubleshooting/
+---
+
+# HVM Troubleshooting #
+
+## HVM pauses on boot, followed by 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.
+
+## Can't start an OS in an HVM / "Probing EDD (edd=off to disable!... ok" message ##
+
+If you see a screen popup with SeaBios and 4 lines, last one being `Probing EDD (edd=off to disable!... ok`, then enter the following command from a `dom0` prompt:
+
+    qvm-prefs <HVMname> kernel ""
+
+## HVM crashes when booting from ISO ##
+If your HVM crashes when trying to boot an ISO, first ensure that ` qvm-prefs <HVMname>` is empty, as shown above. 
+If this doesn't help, then disable memory balancing and set the minimum memory to 2GB.
+
+You can disable memory-balancing in the settings, under the “Advanced” tab.
+
+To give the VM a RAM of 2GB, open a terminal in `dom0` and enter:
+
+    qvm-prefs <HVMname> memory 2000
+