From 9d40292bf98919b71b3ce2b610871c6ab70c7b7f Mon Sep 17 00:00:00 2001
From: unman <unman@thirdeyesecurity.org>
Date: Wed, 19 Apr 2017 23:27:01 +0100
Subject: [PATCH] Explain how to boot with HVM kernel errors.

---
 managing-os/linux-hvm-tips.md | 52 +++++++++++++++++------------------
 1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/managing-os/linux-hvm-tips.md b/managing-os/linux-hvm-tips.md
index 554fbbb3..c1c99fa3 100644
--- a/managing-os/linux-hvm-tips.md
+++ b/managing-os/linux-hvm-tips.md
@@ -14,60 +14,58 @@ Tips for Linux in HVM domain
 How to fix bootup kernel error 
 -------------------------------
 
-This concerns the following:
+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]
 
-This has been tested with Qubes `R3.2-RC3`. Note that the issue may be related
-to the `bochs_drm` video driver. To fix this:
+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`.
-
-2.  Find the line which starts:
-
+1.  Find the line which starts:
     ~~~
     GRUB_CMDLINE_LINUX=
     ~~~
-
-3.  Remove this text from that line:
-
+1.  Remove this text from that line:
     ~~~
     rhgb
     ~~~
-
-4.  Add this text to that line:
-
+1.  Add this text to that line:
     ~~~
     modprobe.blacklist=bochs_drm
     ~~~
-
-5.  Run this command:
-
+1.  Run this command:
     ~~~
     grub2-mkconfig --output=/boot/grub2/grub.cfg
     ~~~
 
-The HVM should no longer display the error if it's related to the `bochs_drm`
-kernel driver.
+The HVM should now start normally.
+
 
 Screen resolution
 -----------------
 
-Some kernel/Xorg combination use only 640x480 in HVM, which is quite small. To enable maximum resolution, some changes in Xorg configuration are needed:
-
+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 run as root):
+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
     ~~~
 
-2.  Add HorizSync line to Monitor section, it should look something like:
-
+1.  Add HorizSync line to Monitor section, it should look something like:
     ~~~
     Section "Monitor"
             Identifier   "Monitor0"
@@ -77,8 +75,7 @@ To achieve it (all commands run as root):
     EndSection
     ~~~
 
-3.  Change driver to "vesa" in Device section:
-
+1.  Change driver to "vesa" in Device section:
     ~~~
     Section "Device"
             # (...)
@@ -90,9 +87,10 @@ To achieve it (all commands run as root):
     EndSection
     ~~~
 
-Now you should get at least 1280x1024 and be able to choose other modes.
+Now you should get resolution of at least 1280x1024 and should be able to choose other modes.
 
 Qubes agents
 ------------
 
-Linux Qubes agents are written with PV domain in mind, but it looks to be possible to run them also in HVM domain. However some work is required to achieve it. Check [this thread](https://groups.google.com/group/qubes-devel/browse_thread/thread/081df4a43e49e7a5).
+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).