Created attachment 873794 [details]
This is guest xml

Description of problem:

Libvirt-cim should ensure to keep/define the <controller> elements.
Otherwise the domain xml generated by libvirt-cim lacks pci controller,
so that libvirtd will reject the change from cim client.

Version-Release number of selected component (if applicable):
# rpm -q libvirt-cim
libvirt-cim-0.6.3-6.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. define a guest like:

# virsh dumpxml test
<domain type='kvm'>
  <name>test</name>
  <uuid>1536d0ce-e8e8-11e2-9094-5fff350163f4</uuid>
  <memory dumpCore='on' unit='KiB'>1048576</memory>
  <currentMemory unit='KiB'>1048576</currentMemory>
  <vcpu placement='static'>1</vcpu>
  <os>
    <type arch='x86_64' machine='rhel6.4.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
  </features>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='kvm' type='raw' cache='none'/>
      <source file='/tmp/test.img'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <shareable/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hdc' bus='ide'/>
      <readonly/>
      <address type='drive' controller='0' bus='1' target='0' unit='0'/>
    </disk>
    <controller type='usb' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <serial type='pty'>
      <target port='0'/>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='tablet' bus='usb'/>
    <input type='mouse' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1' keymap='en-us'>
      <listen type='address' address='127.0.0.1'/>
    </graphics>
    <video>
      <model type='cirrus' vram='9216' heads='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </memballoon>
  </devices>
</domain>

2. Then change machine property from 'rhel6.4.0' to 'fedora' using test_machine.xml

# cat test_machine.xml 
<?xml version="1.0" encoding="utf-8" ?>
<CIM CIMVERSION="2.0" DTDVERSION="2.0">
<MESSAGE ID="4711" PROTOCOLVERSION="1.0">
<SIMPLEREQ>
<METHODCALL NAME="ModifySystemSettings">
<LOCALINSTANCEPATH>
 <LOCALNAMESPACEPATH>
  <NAMESPACE NAME="root"></NAMESPACE><NAMESPACE NAME="virt"></NAMESPACE>
 </LOCALNAMESPACEPATH>
 <INSTANCENAME CLASSNAME="KVM_VirtualSystemManagementService">
  <KEYBINDING NAME="CreationClassName"><KEYVALUE VALUETYPE="string">KVM_VirtualSystemManagementService</KEYVALUE></KEYBINDING>
  <KEYBINDING NAME="Name"><KEYVALUE VALUETYPE="string">Management Service</KEYVALUE></KEYBINDING>
  <KEYBINDING NAME="SystemCreationClassName"><KEYVALUE VALUETYPE="string">KVM_HostSystem</KEYVALUE></KEYBINDING>
  <KEYBINDING NAME="SystemName"><KEYVALUE VALUETYPE="string">unknown</KEYVALUE></KEYBINDING>
 </INSTANCENAME>
</LOCALINSTANCEPATH>

<PARAMVALUE NAME="SystemSettings" PARAMTYPE="string">
 <VALUE>
instance of KVM_VirtualSystemSettingData{
 VirtualSystemIdentifier ="test";
 Machine = "fedora";
};
 </VALUE>
</PARAMVALUE>

</METHODCALL>
</SIMPLEREQ>
</MESSAGE>
</CIM>

# wbemexec test_machine.xml 
<?xml version="1.0" encoding="utf-8"?>
<CIM CIMVERSION="2.0" DTDVERSION="2.0">
<MESSAGE ID="4711" PROTOCOLVERSION="1.0">
<SIMPLERSP>
<METHODRESPONSE NAME="ModifySystemSettings">
<ERROR CODE="1" DESCRIPTION="CIM_ERR_FAILED: Failed to define domain: XML error: No PCI buses available"/>
</METHODRESPONSE>
</SIMPLERSP>
</MESSAGE>
</CIM>

As we see, libvirtd said "No PCI buses available", the request is rejected.
The domain xml libvirt-cim generated (check it from libvirt log) is:
<domain type='kvm'>
  <name>test</name>
  <on_poweroff>destroy</on_poweroff>
  <on_crash>destroy</on_crash>
  <uuid>1536d0ce-e8e8-11e2-9094-5fff350163f4</uuid>
  <clock offset="utc"/>
  <os>
    <type machine="fedora">hvm</type>
    <boot dev="hd"/>
  </os>
  <features>
    <acpi/>
  </features>
  <currentMemory>1048576</currentMemory>
  <memory dumpCore="on">1048576</memory>
  <vcpu>1</vcpu>
  <cputune>
    <shares>0</shares>
  </cputune>
  <devices>
    <disk type="file" device="disk">
      <driver name="kvm" type="raw" cache="none"/>
      <source file="/tmp/test.img"/>
      <target dev="hda" bus="ide"/>
      <readonly/>
      <shareable/>
    </disk>
    <disk type="file" device="cdrom">
      <driver name="qemu" type="raw"/>
      <target dev="hdc" bus="ide"/>
      <readonly/>
    </disk>
    <input type="tablet" bus="usb"/>
    <input type="mouse" bus="ps2"/>
    <serial type="pty">
      <source/>
      <target port="0"/>
    </serial>
    <console type="pty">
      <source/>
      <target port="0"/>
    </console>
    <graphics type="vnc" port="-1" autoport="yes" listen="127.0.0.1" keymap="en-us"/>
    <emulator>/usr/libexec/qemu-kvm</emulator>
  </devices>
</domain>

This xml generated by libvirt-cim lacks pci controller.