Bug 1585931

(In reply to Jing Qi from comment #0)
> Description of problem:
> Cold unplug memory device in a running vm, the currentMemory is reduced.
> 
> Version-Release number of selected component (if applicable):
> 
> 
> How reproducible:
> 
> 
> Steps to Reproduce:
> 1. Start a vm and dumpxml
>   <maxMemory slots='8' unit='KiB'>2560000</maxMemory>
>   <memory unit='KiB'>1036288</memory>
>   <currentMemory unit='KiB'>1036288</currentMemory>
>   <vcpu placement='static' cpuset='0-3'>4</vcpu>
>   .....
>    <cpu>
>     <numa>
>       <cell id='0' cpus='0-1' memory='512000' unit='KiB' memAccess='shared'/>
>     </numa>
>   </cpu>
>   ....
>    <devices>
>   ....
>    <memory model='dimm'>
>       <target>
>         <size unit='KiB'>524288</size>
>         <node>0</node>
>       </target>
>       <address type='dimm' slot='0'/>

This does not look like a live XML as the <alias> element is missing.

>     </memory>
>   </devices>

Please attach untruncated XMLs

Created attachment 1447752 [details]
the domain xml

(In reply to Jing Qi from comment #3)
> Created attachment 1447752 [details]
> the domain xml

That is not a live XML.

Please attach live XML, after you start up the VM and both live and config/inactive XML after you unplug the device.

Created attachment 1448566 [details]
The running xml

Created attachment 1448567 [details]
The running xml after detach

Created attachment 1448569 [details]
the inactive xml after detach

I need to correct the description of the bug.  The correct steps are as below.
1. Start a vm and dumpxml
  <maxMemory slots='8' unit='KiB'>2560000</maxMemory>
  <memory unit='KiB'>1036288</memory>
  <currentMemory unit='KiB'>512000</currentMemory>
  <vcpu placement='static' cpuset='0-3'>4</vcpu>
  .....
   <cpu>
    <numa>
      <cell id='0' cpus='0-1' memory='512000' unit='KiB' memAccess='shared'/>
    </numa>
  </cpu>
  ....
   <devices>
  ....
   <memory model='dimm'>
      <target>
        <size unit='KiB'>524288</size>
        <node>0</node>
      </target>
      <address type='dimm' slot='0'/>
    </memory>
  </devices>


2. Then do "virsh dumpxml" for several times. At first, the currentMemory is "1036288"

#virsh dumpxml avocado-vt-vm-numa2 |grep -i memory -A5
  <maxMemory slots='8' unit='KiB'>2560000</maxMemory>
  <memory unit='KiB'>1036288</memory>
  <currentMemory unit='KiB'>1036288</currentMemory>
  <vcpu placement='static' cpuset='0-3'>4</vcpu>
  <resouces>
     <partition>/machine</partition>
  </resources>
  <os>
  
  Run the "virsh dumpxml" for several times or wait a while. the currentMemory become "512000".
 #virsh dumpxml avocado-vt-vm-numa2 |grep -i memory -A5
  <maxMemory slots='8' unit='KiB'>2560000</maxMemory>
  <memory unit='KiB'>1036288</memory>
  <currentMemory unit='KiB'>512000</currentMemory>
  <vcpu placement='static' cpuset='0-3'>4</vcpu>
  <resouces>
     <partition>/machine</partition>
  </resources>
  <os>

 It wasn't affected by the cold unplug, and it's decreased automatically. It may be as expected. Can you please help to confirm?

And if hotplug the memory after the machine is started, the currentmemory will increase.

b.xml
<memory model='dimm'>
      <target>
        <size unit='KiB'>524288</size>
        <node>0</node>
      </target>
      <address type='dimm' slot='0'/>
    </memory>

# virsh attach-device avocado-vt-vm-numa2 b.xml

And dumpxml the active domain, 
 #virsh dumpxml avocado-vt-vm-numa2 |grep -i memory -A5
  <maxMemory slots='8' unit='KiB'>2560000</maxMemory>
  <memory unit='KiB'>1036288</memory>
  <currentMemory unit='KiB'>1036288</currentMemory>
  <vcpu placement='static' cpuset='0-3'>4</vcpu>
  <resouces>
     <partition>/machine</partition>
  </resources>
  <os>

The behaviors are different when the above xml is attached and it's in the domain xml before started. Is it as expected?

This bug is going to be addressed in the next major release.

With some investigation, the bug need be closed since the issue in the description can't be reproduced in current release.
And the questions in the comment 8 & 9 should be expected.  

libvirt-5.5.0-1.virtcov.el8.x86_64