Description of problem:
qemu 0.12 introduced -chardev arguments, but libvirt 0.8.7 doesn't know how to parse those back into XML.  As a result, the conversion from qemu command line to libvirt XML ends up sucking in the <qemu:commandline> namespace, even though a proper conversion to <devices> would be more appropriate.

Round-tripping ALL libvirt-generated qemu command lines back to libvirt is not quite possible, at least, not without further enhancing virsh domxml-to-native to support a new 'argz' or 'shell' mode (where the arguments are either NUL-terminated or shell-quoted); the current output is ambiguous for any qemu argument that legitimately contains whitespace (such as smbios entries).  But that may also be worth fixing upstream.

Version-Release number of selected component (if applicable):
libvirt-0.8.7-4.el6

How reproducible:
100%

Steps to Reproduce:
1. find a simple libvirt XML for a domain with at least one device. To save me typing, I did cp libvirt/tests/qemuxml2argvdata/qemuxml2argv-console-virtio.xml dom.xml
2. convert the xml to native: virsh domxml-to-native qemu-argv dom.xml > dom.args
3. try to convert it back: virsh domxml-from-native dom.args

Actual results:
the resulting output is full of <qemu:arg> entries that libvirt couldn't parse, even though the original XML was completely understood by libvirt to generate the qemu command line in the first place

Expected results:
the output should be more or less identical to the original input (this doesn't completely have to be true, since libvirt may have modernized old xml constructs into newer), at least to the point of no <qemu:...> namespace elements.

Additional info:
So far, no one has reported this as a bug upstream, so it might not be a very-often used feature.  But since RHEL supports only libvirt and not direct qemu invocation, getting this to work well would ease conversion from people with qemu setups into supported libvirt setups.