## 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:
