[tom@localhost ~]$ ls -l /usr/lib/udev/rules.d/65-kvm.rules
ls: cannot access /usr/lib/udev/rules.d/65-kvm.rules: No such file or directory
[tom@localhost ~]$ grep kvm /usr/lib/udev/rules.d/70-uaccess.rules 
SUBSYSTEM=="misc", KERNEL=="kvm", TAG+="uaccess"
[tom@localhost ~]$ sudo getfacl /dev/kvm 
getfacl: Removing leading '/' from absolute path names
# file: dev/kvm
# owner: root
# group: root
user::rw-
user:tom:rw-
group::---
mask::rw-
other::---

[tom@localhost ~]$ grep test /etc/libvirt/qemu.conf 
user = "test"
group = "test"
[tom@localhost ~]$ sudo systemctl start libvirtd
[tom@localhost ~]$ journalctl -b -f -u libvirtd
-- Logs begin at Sat 2015-10-24 08:33:25 HKT. --
Oct 24 12:48:49 localhost systemd[1]: Starting Virtualization daemon...
Oct 24 12:48:50 localhost systemd[1]: Started Virtualization daemon.
Oct 24 12:48:50 localhost libvirtd[410]: libvirt version: 1.2.20
Oct 24 12:48:50 localhost libvirtd[410]: Cannot check dnsmasq binary /sbin/dnsmasq: No such file or directory
Oct 24 12:48:50 localhost libvirtd[410]: direct firewall backend requested, but /sbin/ebtables is not available: No such file or directory
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to initialize a valid firewall backend
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to find path for dmidecode binary
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to find path for dmidecode binary
Oct 24 12:49:28 localhost libvirtd[410]: failed to connect to monitor socket: No such process
Oct 24 12:49:28 localhost libvirtd[410]: internal error: process exited while connecting to monitor: 
                                         (process:466): GLib-WARNING **: gmem.c:482: custom memory allocation vtable not supported
                                         Could not access KVM kernel module: Permission denied
                                         failed to initialize KVM: Permission denied
^C
[tom@localhost ~]$ sudo chown root:test /dev/kvm
[tom@localhost ~]$ journalctl -b -f -u libvirtd
-- Logs begin at Sat 2015-10-24 08:33:25 HKT. --
Oct 24 12:48:50 localhost libvirtd[410]: libvirt version: 1.2.20
Oct 24 12:48:50 localhost libvirtd[410]: Cannot check dnsmasq binary /sbin/dnsmasq: No such file or directory
Oct 24 12:48:50 localhost libvirtd[410]: direct firewall backend requested, but /sbin/ebtables is not available: No such file or directory
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to initialize a valid firewall backend
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to find path for dmidecode binary
Oct 24 12:48:50 localhost libvirtd[410]: internal error: Failed to find path for dmidecode binary
Oct 24 12:49:28 localhost libvirtd[410]: failed to connect to monitor socket: No such process
Oct 24 12:49:28 localhost libvirtd[410]: internal error: process exited while connecting to monitor: 
                                         (process:466): GLib-WARNING **: gmem.c:482: custom memory allocation vtable not supported
                                         Could not access KVM kernel module: Permission denied
                                         failed to initialize KVM: Permission denied
Oct 24 12:50:04 localhost libvirtd[410]: failed to connect to monitor socket: No such process
Oct 24 12:50:04 localhost libvirtd[410]: internal error: process exited while connecting to monitor: 
                                         (process:476): GLib-WARNING **: gmem.c:482: custom memory allocation vtable not supported
                                         Could not access KVM kernel module: Permission denied
                                         failed to initialize KVM: Permission denied
^C