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Bug 1366498 - Failed to save guest with vhostuser network device with mult-queues.
Summary: Failed to save guest with vhostuser network device with mult-queues.
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.3
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: rc
: ---
Assignee: Victor Kaplansky
QA Contact: Pei Zhang
URL:
Whiteboard:
Depends On: 1321299 1335865
Blocks:
TreeView+ depends on / blocked
 
Reported: 2016-08-12 06:54 UTC by chhu
Modified: 2018-02-06 06:41 UTC (History)
17 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-02-06 06:41:09 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description chhu 2016-08-12 06:54:09 UTC 
Description of problems:
Failed to save guest with vhostuser network device with mult-queues.

Version:
libvirt-2.0.0-4.el7.x86_64
qemu-kvm-rhev-2.6.0-19.el7.x86_64
kernel: 3.10.0-489.el7.x86_64
openvswitch-dpdk-2.5.0-4.el7.x86_64
dpdk-2.2.0-3.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Start VM in libvirt with vhostuser multi-queues.
# virsh start r7-raw
# virsh list --all
 Id    Name                           State
----------------------------------------------------
 4     r7-raw                         running

# virsh dumpxml r7-raw
<domain type='kvm' id='4'>
  <name>r7-raw</name>
  <uuid>2ccf719b-d968-48e6-a37f-8f3d3b41877a</uuid>
  <memory unit='KiB'>1024000</memory>
  <currentMemory unit='KiB'>1024000</currentMemory>
  <memoryBacking>
    <hugepages>
      <page size='2048' unit='KiB' nodeset='0'/>
    </hugepages>
  </memoryBacking>
  <vcpu placement='static'>4</vcpu>
  <numatune>
    <memory mode='strict' nodeset='0'/>
  </numatune>
......
  <cpu mode='host-model'>
    <model fallback='allow'/>
    <numa>
      <cell id='0' cpus='0-1' memory='1024000' unit='KiB' memAccess='shared'/>
    </numa>
  </cpu>
......
    <interface type='vhostuser'>
      <mac address='52:54:00:bb:25:74'/>
      <source type='unix' path='/var/run/openvswitch/vhost-user1' mode='client'/>
      <model type='virtio'/>
      <driver queues='4'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
......

2. Try to save the guest.
# virsh save r7-raw r7-raw.save
error: Failed to save domain r7-raw to r7-raw.save
error: internal error: unable to execute QEMU command 'migrate': Migration disabled: vhost-user backend lacks VHOST_USER_PROTOCOL_F_LOG_SHMFD feature.

Actual results:
In step2: Try to save the guest failed with error.

Expected results:
In step2: The guest is saved successfully.

Logs in libvirtd:
2016-08-10 04:16:59.345+0000: 21770: debug : qemuMonitorJSONCheckError:376 : unable to execute QEMU command {"execute":"migrate","arguments":{"detach":true,"blk":false,"inc":false,"uri":"fd:migrate"},"id":"libvirt-48"}: {"id":"libvirt-48","error":{"class":"GenericError","desc":"Migration disabled: vhost-user backend lacks VHOST_USER_PROTOCOL_F_LOG_SHMFD feature."}}
Comment 3 Michal Privoznik 2017-03-23 12:18:07 UTC 
So, after some examination I don't think this is a libvirt bug. If I understand correctly, the capability that qemu is missing - it's in fact the openvswitch that is missing the capability. Switching to qemu to confirm that.
Comment 4 Victor Kaplansky 2017-06-06 12:44:40 UTC 
Looks like openvswitch indeed doesn't set VHOST_USER_PROTOCOL_F_LOG_SHMFD.

Flavio, could you check if this is the case?

Thanks.
Comment 7 Flavio Leitner 2017-08-16 14:11:34 UTC 
(In reply to Victor Kaplansky from comment #4)
> Looks like openvswitch indeed doesn't set VHOST_USER_PROTOCOL_F_LOG_SHMFD.
> 
> Flavio, could you check if this is the case?

That was added to DPDK 16.11, so our 2.7.2 package should be ok.
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