I am using libvirt with lxc to create fedora 16 & 18 containers on fedora 18 host.

first I did the setup with libvirt 1.0.3 and everything worked fine, then after upgrading to libvirt 1.0.4, I could not create character device on the guests :

Test on the guest1 : 

# ls -l /dev

total 0

lrwxrwxrwx. 1 root root   10 Apr 17 21:18 console -> /dev/pts/0

lrwxrwxrwx. 1 root root   11 Apr 17 21:18 core -> /proc/kcore

lrwxrwxrwx. 1 root root   13 Apr 17 21:18 fd -> /proc/self/fd

crw-rw-rw-. 1 root root 1, 7 Apr 17 21:18 full

drwxr-xr-x. 2 root root    0 Apr 17 21:18 hugepages

prw-------. 1 root root    0 Apr 17 21:18 initctl

srw-rw-rw-. 1 root root    0 Apr 17 21:18 log

drwxrwxrwt. 2 root root   40 Apr 17 21:18 mqueue

crw-rw-rw-. 1 root root 1, 3 Apr 17 21:18 null

crw-rw-rw-. 1 root root 5, 2 Apr 18 10:31 ptmx

drwxr-xr-x. 2 root root    0 Apr 17 21:18 pts

crw-r--r--. 1 root root 1, 8 Apr 17 21:19 random

drwxrwxrwt. 2 root root   40 Apr 17 21:18 shm

lrwxrwxrwx. 1 root root   15 Apr 17 21:18 stderr -> /proc/self/fd/2

lrwxrwxrwx. 1 root root   15 Apr 17 21:18 stdin -> /proc/self/fd/0

lrwxrwxrwx. 1 root root   15 Apr 17 21:18 stdout -> /proc/self/fd/1

lrwxrwxrwx. 1 root root   10 Apr 17 21:18 tty1 -> /dev/pts/0

crw-rw-rw-. 1 root root 1, 9 Apr 17 21:18 urandom

crw-rw-rw-. 1 root root 1, 5 Apr 17 21:18 zero  

# rm -f /dev/random      (successful)

# mknod random c 1 8

mknod: `random': Operation not permitted

Config on the host :

knowing that selinux is set to permissive and c 1:8 rwm is in the cgroup devices list of the guest1 

# cat /sys/fs/cgroup/devices/libvirt/lxc/guest1/devices.list