I have the same problem using raw lvm logical volumes as disk on Ubuntu 18.04.
When i try to start a vm with virt-manager qemu says Permission denied on device.
The lvm uses device mapper to map the logical volumes so i need to handle devices like
brw-rw---- 1 libvirt-qemu kvm 253, 4 mar 17 13:24 /dev/dm-4
After a bunch of failure attempts to start the vm machine, the following steps was successful:
I run the aa-logprof (apparmor-utils package) util to update the apparmor profiles using the syslog, and
i add the following line in /etc/apparmor.d/abstractions/libvirt-qemu
...
/dev/dm* krw,
just before the /dev/net/tun rw, line.
If the line already exists just replace "rw" with "krw" to permit file lock operations.
I have the same problem using raw lvm logical volumes as disk on Ubuntu 18.04.
When i try to start a vm with virt-manager qemu says Permission denied on device.
The lvm uses device mapper to map the logical volumes so i need to handle devices like
brw-rw---- 1 libvirt-qemu kvm 253, 4 mar 17 13:24 /dev/dm-4
After a bunch of failure attempts to start the vm machine, the following steps was successful:
I run the aa-logprof (apparmor-utils package) util to update the apparmor profiles using the syslog, and d/abstractions/ libvirt- qemu
i add the following line in /etc/apparmor.
...
/dev/dm* krw,
just before the /dev/net/tun rw, line.
If the line already exists just replace "rw" with "krw" to permit file lock operations.
Now it seems vm runs well again.