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Bug 1470582 - [UPDATES] Target CPU mode custom does not match source host-model
Summary: [UPDATES] Target CPU mode custom does not match source host-model
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.4
Hardware: x86_64
OS: Linux
high
high
Target Milestone: rc
: ---
Assignee: Jiri Denemark
QA Contact: Luyao Huang
URL:
Whiteboard:
Depends On: 1463957
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-07-13 09:06 UTC by Jaroslav Reznik
Modified: 2017-08-01 11:30 UTC (History)
29 users (show)

Fixed In Version: libvirt-3.2.0-14.el7_4.1
Doc Type: Bug Fix
Doc Text:
Cause: Previously libvirt transformed a host-model CPU into a real model everytime it needed to know the actual CPU model. Current libvirt does this transformation only once when a new domain with a host-model CPU is started to make sure the same CPU model is used for the whole life time of the domain. Consequence: When libvirtd is restarted after an upgrade from an earlier version, it reconnects to running domains some of which might have been started with a host-model CPU that was not transformed into an actual model. Current libvirt does not expect a host-model CPU in a definition of a running domain which caused several issues when trying to migrate such domain. Fix: Libvirt transforms host-model CPUs into actual CPU models of all running domains when reconnecting to them. Result: Domains started on RHEL-7.3 can be successfully migrated even after libvirt is upgraded to a newer version.
Clone Of: 1463957
Environment:
Last Closed: 2017-08-01 11:30:30 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2017:2334 0 normal SHIPPED_LIVE libvirt bug fix update 2017-08-14 22:56:05 UTC

Description Jaroslav Reznik 2017-07-13 09:06:28 UTC 
This bug has been copied from bug #1463957 and has been proposed to be backported to 7.4 z-stream (EUS).
Comment 5 Luyao Huang 2017-07-17 09:09:17 UTC 
Verify this bug with libvirt-3.2.0-14.el7_4.1.x86_64:

S1: start guest on 7.3 -> update to 7.4 -> migrate guest to 7.4 host

1. prepare 3 guest, which have custom, host-model and host-passthrough cpu:

# virsh dumpxml r7-mig
...
  <cpu mode='custom' match='minimum'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'/>
...

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
...

2. start guest:

# virsh start r7-mig3
Domain r7-mig3 started

# virsh start r7-mig2
Domain r7-mig2 started

# virsh start r7-mig
Domain r7-mig started

3. update libvirt to 7.4:

yum update libvirt* qemu*

4. recheck guest xml:

# virsh dumpxml r7-mig
  <cpu mode='custom' match='minimum' check='partial'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>

# virsh dumpxml r7-mig2
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>


5. migrate to rhel7.4 host (same cpu with source):

# virsh migrate r7-mig qemu+ssh://target/system --live

# virsh migrate r7-mig2 qemu+ssh://target/system --live

# virsh migrate r7-mig3 qemu+ssh://target/system --live


6. recheck guest one the target host:

# virsh dumpxml r7-mig | grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig2 | grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 | grep -A28 '<cpu'
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>

7. migrate back to source:

# virsh migrate r7-mig qemu+ssh://source/system --live

# virsh migrate r7-mig2 qemu+ssh://source/system --live

# virsh migrate r7-mig3 qemu+ssh://source/system --live

8. recheck guest in the source host:

# virsh dumpxml r7-mig2 |grep -A28 "<cpu"
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig |grep -A28 "<cpu"
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 |grep -A28 "<cpu"
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>


9. check the qemu command and log in guest log


S2: guest migrate from 7.3 host -> update to 7.4  -> migrate to 7.4

1. prepare 3 guest, which have custom, host-model and host-passthrough cpu:

# virsh dumpxml r7-mig
...
  <cpu mode='custom' match='minimum'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'/>
...

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
...


2. start and migrate to 7.3 host:


# virsh start r7-mig3
Domain r7-mig3 started

# virsh start r7-mig2
Domain r7-mig2 started

# virsh start r7-mig
Domain r7-mig started

# virsh migrate r7-mig qemu+ssh://target/system --live

# virsh migrate r7-mig2 qemu+ssh://target/system --live

# virsh migrate r7-mig3 qemu+ssh://target/system --live

3. check the guest xml in target:

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>
...

# virsh dumpxml r7-mig

  <cpu mode='custom' match='exact'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>

4. update target and source host to 7.4:

# yum update libvirt* qemu*

5. recheck guest xml:

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>

# virsh dumpxml r7-mig2 |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 |grep -A28 '<cpu'
  <cpu mode='host-passthrough' check='none'>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>

9. migrate to source host:

10. recheck the guest xml:

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig2 |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

11. check the qemu command and log in guest log



S3: start guest on 7.3 -> update to 7.4 -> migrate guest to 7.4 host with --xml

1. prepare 3 guest, which have custom, host-model and host-passthrough cpu:

# virsh dumpxml r7-mig
...
  <cpu mode='custom' match='minimum'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'/>
...

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
...

2. start guest:

# virsh start r7-mig3
Domain r7-mig3 started

# virsh start r7-mig2
Domain r7-mig2 started

# virsh start r7-mig
Domain r7-mig started

3. update libvirt to 7.4:

yum update libvirt* qemu*

4. recheck guest xml:

# virsh dumpxml r7-mig
  <cpu mode='custom' match='minimum' check='partial'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>

# virsh dumpxml r7-mig2
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>


5. migrate to rhel7.4 host the --xml (same cpu with source):
# virsh dumpxml r7-mig2 --migratable > /tmp/r7-mig2.xml 
# virsh migrate r7-mig2 qemu+ssh://target/system --live --xml /tmp/r7-mig2.xml

# virsh dumpxml r7-mig --migratable > /tmp/r7-mig.xml 
# virsh migrate r7-mig qemu+ssh://target/system --live --xml /tmp/r7-mig.xml

# virsh dumpxml r7-mig3 --migratable > /tmp/r7-mig3.xml 
# virsh migrate r7-mig3 qemu+ssh://target/system --live --xml /tmp/r7-mig3.xml



6. recheck guest one the target host:

# virsh dumpxml r7-mig | grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig2 | grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 | grep -A28 '<cpu'
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>

7. migrate back to source:

# virsh dumpxml r7-mig3 --migratable > /tmp/r7-mig3.xml
# virsh migrate r7-mig3 qemu+ssh://source/system --live --xml /tmp/r7-mig3.xml

# virsh dumpxml r7-mig2 --migratable > /tmp/r7-mig2.xml
# virsh migrate r7-mig2 qemu+ssh://source/system --live --xml /tmp/r7-mig2.xml

# virsh dumpxml r7-mig --migratable > /tmp/r7-mig.xml
# virsh migrate r7-mig qemu+ssh://source/system --live --xml /tmp/r7-mig.xml


8. recheck guest in the source host:

# virsh dumpxml r7-mig2 |grep -A28 "<cpu"
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig |grep -A28 "<cpu"
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 |grep -A28 "<cpu"
  <cpu mode='host-passthrough' check='none'>
    <numa>
      <cell id='0' cpus='0-2' memory='524288' unit='KiB'/>
      <cell id='1' cpus='3-5' memory='524288' unit='KiB'/>
    </numa>
  </cpu>


9. check the qemu command and log in guest log


S4: guest migrate from 7.3 host -> update to 7.4  -> migrate to 7.4 with --xml

1. prepare 3 guest, which have custom, host-model and host-passthrough cpu:

# virsh dumpxml r7-mig
...
  <cpu mode='custom' match='minimum'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'/>
...

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
...


2. start and migrate to 7.3 host:


# virsh start r7-mig3
Domain r7-mig3 started

# virsh start r7-mig2
Domain r7-mig2 started

# virsh start r7-mig
Domain r7-mig started

# virsh migrate r7-mig qemu+ssh://target/system --live

# virsh migrate r7-mig2 qemu+ssh://target/system --live

# virsh migrate r7-mig3 qemu+ssh://target/system --live

3. check the guest xml in target:

# virsh dumpxml r7-mig3
...
  <cpu mode='host-passthrough'>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>
...

# virsh dumpxml r7-mig2
...
  <cpu mode='host-model'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>
...

# virsh dumpxml r7-mig

  <cpu mode='custom' match='exact'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>

4. update target and source host to 7.4:

# yum update libvirt* qemu*

5. recheck guest xml:

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='allow'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>

# virsh dumpxml r7-mig2 |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='allow'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig3 |grep -A28 '<cpu'
  <cpu mode='host-passthrough' check='none'>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='ht'/>
    <feature policy='require' name='monitor'/>
    <feature policy='require' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='require' name='ibs'/>
    <feature policy='require' name='skinit'/>
    <feature policy='require' name='wdt'/>
    <feature policy='require' name='lwp'/>
    <feature policy='require' name='tce'/>
    <feature policy='require' name='nodeid_msr'/>
    <feature policy='require' name='topoext'/>
    <feature policy='require' name='perfctr_core'/>
    <feature policy='require' name='perfctr_nb'/>

9. migrate to source host:

# virsh dumpxml r7-mig --migratable > /tmp/r7-mig.xml
# virsh migrate r7-mig qemu+ssh://source/system --live --xml /tmp/r7-mig.xml

# virsh dumpxml r7-mig2 --migratable > /tmp/r7-mig2.xml
# virsh migrate r7-mig2 qemu+ssh://source/system --live --xml /tmp/r7-mig2.xml

# virsh dumpxml r7-mig3 --migratable > /tmp/r7-mig3.xml
# virsh migrate r7-mig3 qemu+ssh://source/system --live --xml /tmp/r7-mig3.xml


10. recheck the guest xml:

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig2 |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

# virsh dumpxml r7-mig |grep -A28 '<cpu'
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>Opteron_G5</model>
    <feature policy='disable' name='invtsc'/>
    <feature policy='require' name='vme'/>
    <feature policy='disable' name='ht'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='osxsave'/>
    <feature policy='require' name='bmi1'/>
    <feature policy='require' name='mmxext'/>
    <feature policy='require' name='fxsr_opt'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='disable' name='extapic'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='require' name='osvw'/>
    <feature policy='disable' name='ibs'/>
    <feature policy='disable' name='skinit'/>
    <feature policy='disable' name='wdt'/>
    <feature policy='disable' name='lwp'/>
    <feature policy='disable' name='tce'/>
    <feature policy='disable' name='nodeid_msr'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='perfctr_core'/>
    <feature policy='disable' name='perfctr_nb'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='svm'/>

11. check the qemu command and log in guest log
Comment 6 Luyao Huang 2017-07-17 09:29:31 UTC 
Also retest with qemu-kvm (qemu-kvm-1.5.3-141.el7_4.1.x86_64) and libvirt (libvirt-3.2.0-14.el7_4.1.x86_64) with the same steps in comment 5, migrate success and no regression.
Comment 7 Luyao Huang 2017-07-17 09:45:09 UTC 
Test some basic test scenario with r7-mig, r7-mig2 and r7-mig3 (xml check comment 5), no regression been found.
Comment 8 Luyao Huang 2017-07-18 01:14:12 UTC 
Verify this bug with comment 5 and comment 6 and comment 7.
Comment 9 Luyao Huang 2017-07-19 07:04:08 UTC 
Hi Jirka,

Our auto job catch a problem on an old cpu model machine, the managedsave and migration have been broken on that machine, here is some info and reproduce steps:

virsh # capabilities 
<capabilities>

  <host>
    <uuid>00020003-0004-0005-0006-000700080009</uuid>
    <cpu>
      <arch>x86_64</arch>
      <model>Opteron_G2</model>
      <vendor>AMD</vendor>
      <topology sockets='1' cores='2' threads='1'/>
      <feature name='vme'/>
      <feature name='ht'/>
      <feature name='mmxext'/>
      <feature name='fxsr_opt'/>
      <feature name='3dnowext'/>
      <feature name='3dnow'/>
      <feature name='cmp_legacy'/>
      <feature name='extapic'/>
      <feature name='cr8legacy'/>
      <pages unit='KiB' size='4'/>
      <pages unit='KiB' size='2048'/>
    </cpu>

# virsh dumpxml avocado-vt-vm1
...
  <cpu mode='host-model' check='partial'>
    <model fallback='allow'/>
  </cpu>
...

# virsh dumpxml avocado-vt-vm1
...
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>phenom</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='cx16'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='tsc-deadline'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='arat'/>
    <feature policy='require' name='lahf_lm'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='svm'/>
    <feature policy='disable' name='popcnt'/>
    <feature policy='disable' name='pdpe1gb'/>
    <feature policy='disable' name='rdtscp'/>
    <feature policy='disable' name='abm'/>
    <feature policy='disable' name='sse4a'/>
  </cpu>
...

# virsh dumpxml avocado-vt-vm1 --migratable
...
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='forbid'>phenom</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='vme'/>
    <feature policy='require' name='cx16'/>
    <feature policy='require' name='x2apic'/>
    <feature policy='require' name='tsc-deadline'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='arat'/>
    <feature policy='require' name='lahf_lm'/>
    <feature policy='require' name='cmp_legacy'/>
    <feature policy='require' name='cr8legacy'/>
    <feature policy='disable' name='monitor'/>
    <feature policy='disable' name='svm'/>
  </cpu>
...

# virsh managedsave avocado-vt-vm1

Domain avocado-vt-vm1 state saved by libvirt

# virsh start avocado-vt-vm1 
error: Failed to start domain avocado-vt-vm1
error: operation failed: guest CPU doesn't match specification

And i have test on the libvirt 3.2.0-14, still can reproduce it.

Could you please help to check if this problem is a critical problem that need been fixed on the 7.4.z ?
Comment 11 Luyao Huang 2017-07-19 07:17:14 UTC 
And more information, i tried with different libvirt version and found libvirt-3.2.0-13.el7.x86_64 didn't have this problem, so it is a regression issue introduced in the libvirt-3.2.0-14.el7.x86_64.
Comment 13 Jiri Denemark 2017-07-20 12:51:54 UTC 
(In reply to Luyao Huang from comment #9)
> # virsh start avocado-vt-vm1 
> error: Failed to start domain avocado-vt-vm1
> error: operation failed: guest CPU doesn't match specification

Could you please file a new BZ for this issue? According to the log, the phenom CPU model defined in QEMU contains "npt" feature while libvirt doesn't know anything about the feature. When a new domain is started, QEMU disables this feature on your host, which is ignored by libvirt (it doesn't know the feature), but once restoring the domain it sees QEMU unexpectedly disabled some feature and complains about it.
Comment 14 Luyao Huang 2017-07-21 01:39:22 UTC 
(In reply to Jiri Denemark from comment #13)
> (In reply to Luyao Huang from comment #9)
> > # virsh start avocado-vt-vm1 
> > error: Failed to start domain avocado-vt-vm1
> > error: operation failed: guest CPU doesn't match specification
> 
> Could you please file a new BZ for this issue? According to the log, the
> phenom CPU model defined in QEMU contains "npt" feature while libvirt
> doesn't know anything about the feature. When a new domain is started, QEMU
> disables this feature on your host, which is ignored by libvirt (it doesn't
> know the feature), but once restoring the domain it sees QEMU unexpectedly
> disabled some feature and complains about it.

Got it ! thanks a lot for your help.
Comment 16 Luyao Huang 2017-07-21 04:50:58 UTC 
New bug is bug 1473516
Comment 21 errata-xmlrpc 2017-08-01 11:30:30 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:2334
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