RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1450072 - Libvirt provides a confusing error message on a mediated device hotplug
Summary: Libvirt provides a confusing error message on a mediated device hotplug
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.3
Hardware: Unspecified
OS: Unspecified
low
low
Target Milestone: rc
: ---
Assignee: Erik Skultety
QA Contact: zhe peng
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2017-05-11 13:37 UTC by Erik Skultety
Modified: 2017-08-02 01:32 UTC (History)
3 users (show)

Fixed In Version: libvirt-3.2.0-5.el7
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2017-08-02 00:08:25 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHEA-2017:1846 0 normal SHIPPED_LIVE libvirt bug fix and enhancement update 2017-08-01 18:02:50 UTC

Description Erik Skultety 2017-05-11 13:37:27 UTC 
Description of problem:
When a mediated device is to be hot-plugged to a VM, libvirt returns the following error:

error: Failed to attach device from mdev.xml
error: unsupported configuration: hostdev subsys type 'mdev' not supported

From the message itself, it's not clear whether emitting it is the bug, or just the hot-plug is unsupported. And it this case it should be the latter, since hot-plug is unsupported at the moment.

Version-Release number of selected component (if applicable):
libvirt-3.2.0

How reproducible:
100%

Steps to Reproduce:
1. prepare an mdev device to be attached

$ cat mdev.xml
<hostdev mode='subsystem' type='mdev' model='vfio-pci'>
  <source>
    <address uuid='9c131fd0-cecb-4f99-98e2-c2f7e2de6e11'/>
  </source>
</hostdev>

2. start a VM
3. perform virsh attach-device myvm mdev.xml

Actual results:
error: unsupported configuration: hostdev subsys type 'mdev' not supported

Expected results:
Make it clear, that hot-(un)plugging an mdev device is currently an unsupported operation.

Additional info:
Comment 1 Erik Skultety 2017-05-11 15:00:45 UTC 
Fixed upstream by:

commit f4829df9aeb54d246ee9a816921a78e268ba7701
Refs: [master], {origin/master}, {origin/HEAD}, v3.3.0-27-gf4829df9a
Author:     Erik Skultety <eskultet>
AuthorDate: Thu May 11 15:26:47 2017 +0200
Commit:     Erik Skultety <eskultet>
CommitDate: Thu May 11 16:43:11 2017 +0200

    qemu: Provide a much clearer message on device hot-plug

    Adjust the current message to make it clear, that it is the hotplug
    operation that is unsupported with the given host device type.

    https://bugzilla.redhat.com/show_bug.cgi?id=1450072

    Signed-off-by: Erik Skultety <eskultet>
Comment 4 zhe peng 2017-06-14 08:07:00 UTC 
verify with build:
libvirt-3.2.0-9.virtcov.el7.x86_64

step:

hotplug:
# virsh attach-device rhel7 mdev.xml 
error: Failed to attach device from mdev.xml
error: unsupported configuration: hotplug is not supported for hostdev subsys type 'mdev'

hotunplug:
1.start a guest with mdev.
2.hotunplug
# virsh detach-device rhel7 mdev.xml 
error: Failed to detach device from mdev.xml
error: unsupported configuration: hot unplug is not supported for hostdev subsys type 'mdev'

move to verified.
Comment 5 errata-xmlrpc 2017-08-02 00:08:25 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/RHEA-2017:1846
Comment 6 errata-xmlrpc 2017-08-02 01:32:35 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/RHEA-2017:1846
Note You need to log in before you can comment on or make changes to this bug.