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

97 lines
2.5 KiB
Markdown

---
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).