Bug 1029080

+++ This bug was initially created as a clone of Bug #1029073 +++

This bug is to track the qemu-kvm part of the work.  Output of:
{"execute":"qom-list-types"}
might look like:
{"return":[{"name":"AC97", bus: 'PCI', categories:['sound']}, ...

Upstream QEMU already outputs this info when using 'qemu-kvm -device \?'

The 'bus' field in the output is not mandatory.


Description of problem:
Libvirt does not check whether requested devices are supported by current qemu-kvm binary.  It relies on qemu itself reporting an error, which is fine most of the time.  However, newer versions of libvirt are checking the supported devices when starting the guest.  QEMU also the information to provide list of categories and buses the device can be attached to.

Version-Release number of selected component (if applicable):
libvirt-1.1.1-12.el7
qemu-kvm-1.5.3-19.el7

How reproducible:
101%

Steps to Reproduce:
1. Add the following device into domain XML:

  a.
<interface type='network'>
  <source network='default'/>
  <model type='non-existing_device'/>
</interface>

  b.
<interface type='network'>
  <source network='default'/>
  <model type='AC97'/>
</interface>

2. Start the domain

Actual results:
a. "error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -device non-existing_device,...: Parameter 'driver' expects device type"

b. "error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -device AC97,...: Property '.netdev' not found"


Expected results:
a. "error: unsupported configuration: Device "non-existing_device" is not supported by this QEMU binary"

b. "error: unsupported configuration: Device "AC97" cannot be used as an interface" ("with this QEMU binary"


Additional info:
Libvirt gets enough information to check for case "a." when executing "qom-list-types".
QEMU does not provide enough information to check for proper usage in case "b.".