Arch Linux

SayCheeseOrDie

Member

From: Saint-Petersburg, Russia

Registered: 2016-11-07

Posts: 16

No /dev/kvm on Arch but system is set up correctly

EDIT:
Should've write entire post to realize that I'm stupid.

Doing...

# echo kvm > /etc/modules-load.d/kvm.conf
# echo kvm_amd > /etc/modules-load.d/kvm-amd.conf

...made both modules load on boot and now everything works!
However, I still don't get why they're not loaded by default because I can swear that I've used kvm out of the box in Arch before with no need to enable modules load manually.

Booted Arch on the different machine (laptop on 5 5500U) - same behavior.

Original post:
Hi!

I've recently switched my machine from Debian to Arch. I know for a fact that virtualization is enabled in UEFI settings since on Debian /dev/kvm exist and works perfectly fine.
However, I don't know what's happening with Arch here since there is nothing.

So, here is the output:

lsmod:

$ lsmod | grep kvm
kvm                  1200128  0
irqbypass              16384  1 kvm

Checking in /dev:

$ ls /dev/ | grep kv*
block
disk
kfd
kmsg
rfkill
vhost-vsock

dmesg:

# dmesg | grep kvm
/*NOTHING*/

systemd:

# journalctl -xre | grep kvm
июл 04 20:25:25 amdPC sudo[1718]:   andrew : TTY=pts/0 ; PWD=/home/andrew ; USER=root ; COMMAND=/usr/bin/modprobe kvm
июл 04 20:25:25 amdPC dbus-daemon[444]: [system] Activating via systemd: service name='org.freedesktop.home1' unit='dbus-org.freedesktop.home1.service' requested by ':1.80' (uid=0 pid=1718 comm="sudo modprobe kvm")
июл 04 20:25:22 amdPC sudo[1716]:   andrew : TTY=pts/0 ; PWD=/home/andrew ; USER=root ; COMMAND=/usr/bin/rm /etc/modprobe.d/kvm.conf
июл 04 20:25:22 amdPC dbus-daemon[444]: [system] Activating via systemd: service name='org.freedesktop.home1' unit='dbus-org.freedesktop.home1.service' requested by ':1.79' (uid=0 pid=1716 comm="sudo rm /etc/modprobe.d/kvm.conf")
июл 04 20:24:54 amdPC sudo[1692]:   andrew : TTY=pts/0 ; PWD=/home/andrew ; USER=root ; COMMAND=/usr/bin/modprobe kvm
июл 04 20:24:52 amdPC dbus-daemon[444]: [system] Activating via systemd: service name='org.freedesktop.home1' unit='dbus-org.freedesktop.home1.service' requested by ':1.78' (uid=0 pid=1692 comm="sudo modprobe kvm")

libvirtd status:

● libvirtd.service - Virtualization daemon
     Loaded: loaded (/usr/lib/systemd/system/libvirtd.service; enabled; vendor preset: disabled)
     Active: active (running) since Mon 2022-07-04 20:40:01 MSK; 3s ago
TriggeredBy: ● libvirtd.socket
             ● libvirtd-admin.socket
             ● libvirtd-ro.socket
       Docs: man:libvirtd(8)
             https://libvirt.org
   Main PID: 2392 (libvirtd)
      Tasks: 19 (limit: 32768)
     Memory: 12.0M
        CPU: 90ms
     CGroup: /system.slice/libvirtd.service
             └─2392 /usr/bin/libvirtd --timeout 120

июл 04 20:40:01 amdPC systemd[1]: Starting Virtualization daemon...
июл 04 20:40:01 amdPC systemd[1]: Started Virtualization daemon.
июл 04 20:40:01 amdPC libvirtd[2392]: libvirt version: 8.4.0
июл 04 20:40:01 amdPC libvirtd[2392]: hostname: amdPC
июл 04 20:40:01 amdPC libvirtd[2392]: Не удалось открыть /dev/kvm: Нет такого файла или каталога

Note: last line says "Cannot open /dev/kvm. No such file or directory."

I've managed to get it working once by doing

# modprobe kvm

But after reboot I can't replicate that. Module seems to be loaded, but there is still no /dev/kvm. I've never experienced any problems before with kvm (believe it or not ), so I don't even know where to look besides where I already did.
I've also tried to make this module load on boot by

# echo kvm > /etc/modules-load.d/kvm.conf

But it solved absolutely nothing.

Appreciate any ideas on where I can investigate further.

Thanks!

P.S.: forgot the config.

CPU: AMD 5 5600G (RENOIR)
Chipset: AMD B550
Kernel: Latest Arch-supplied Zen but it behaves the same on vanilla as well.
FS: /boot is using FAT32 and / is btrfs.

...and about few month ago everything worked perfectly fine on Arch as well.

Last edited by SayCheeseOrDie (2022-07-04 18:16:12)

loqs

Member

Registered: 2014-03-06

Posts: 18,967

Re: No /dev/kvm on Arch but system is set up correctly

Please post the full output of

dmesg
lscpu
lsmod