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Description of problem:
libvirt fails to start a guest with an mdev device on s390.
Version-Release number of selected component (if applicable):
libvirt-4.5.0-4.el7
How reproducible:
Steps to Reproduce:
1. define a guest foo with an vfio-ccw mdev
...
<hostdev mode='subsystem' type='mdev' model='vfio-ccw'>
<source>
<address uuid='cfbb5f90-0465-4ed2-8949-248c9eeba1ee'/>
</source>
<address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0003'/>
</hostdev>
...
2. start the guest
# virsh start foo
3.
Actual results:
error: unsupported configuration: <hostdev> attribute 'display' is only
supported with model='vfio-pci'
Expected results:
libvirt starts a guest with an mdev on s390 successfully
Additional info:
upstream commit d54e45b6 introduced a new <hostdev> attribute 'display' which is only supported with vfio-pci backends
- the error is kind of confusing on s390 because the definition doesn't even contain the attribute, because libvirt adds it by default, which is wrong with vfio-ccw
fixed upstream by:
commit d6f97d1338ba9470f7c745fab317d272cde84d38
Refs: v4.7.0-rc2-2-gd6f97d1338
Author: Farhan Ali <alifm.com>
AuthorDate: Thu Aug 30 13:07:34 2018 -0400
Commit: Erik Skultety <eskultet>
CommitDate: Fri Aug 31 14:18:16 2018 +0200
qemu: mdev: Use vfio-pci 'display' property only with vfio-pci mdevs
S390 is aware of both vfio-pci and vfio-ccw devices, so
on S390 the capability QEMU_CAPS_VFIO_PCI_DISPLAY will be
available. Add an extra check to make sure we only set the
display to off for vfio-pci mediated devices. Otherwise we
add display for vfio-ccw device and this breaks vfio-ccw
device qemu command line.
Fixes: d54e45b6e conf: Introduce new <hostdev> attribute 'display'
Signed-off-by: Farhan Ali <alifm.com>
Reviewed-by: Marc Hartmayer <mhartmay.com>
Reviewed-by: Erik Skultety <eskultet>
Package:
libvirt-4.5.0-8.virtcov.el7.s390x
qemu-kvm-ma-2.12.0-12.el7.s390x
kernel-4.14.0-106.el7a.s390x
Steps:
1. Add below in the guest xml and save
<hostdev mode='subsystem' type='mdev' model='vfio-ccw'>
<source>
<address uuid='cfbb5f90-0465-4ed2-8949-248c9eeba1ee'/>
</source>
</hostdev>
2. Dump guest xml
# virsh dumpxml guest |grep hostdev -A4
<hostdev mode='subsystem' type='mdev' managed='no' model='vfio-ccw'>
<source>
<address uuid='cfbb5f90-0465-4ed2-8949-248c9eeba1ee'/>
</source>
</hostdev>
3. Start the guest
# virsh start guest
error: Failed to start domain guest
error: device not found: mediated device 'cfbb5f90-0465-4ed2-8949-248c9eeba1ee' not found
As I do not have mdev device in the beaker machine, so above error messages are as expected.
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/RHSA-2018:3113
Description of problem: libvirt fails to start a guest with an mdev device on s390. Version-Release number of selected component (if applicable): libvirt-4.5.0-4.el7 How reproducible: Steps to Reproduce: 1. define a guest foo with an vfio-ccw mdev ... <hostdev mode='subsystem' type='mdev' model='vfio-ccw'> <source> <address uuid='cfbb5f90-0465-4ed2-8949-248c9eeba1ee'/> </source> <address type='ccw' cssid='0xfe' ssid='0x0' devno='0x0003'/> </hostdev> ... 2. start the guest # virsh start foo 3. Actual results: error: unsupported configuration: <hostdev> attribute 'display' is only supported with model='vfio-pci' Expected results: libvirt starts a guest with an mdev on s390 successfully Additional info: upstream commit d54e45b6 introduced a new <hostdev> attribute 'display' which is only supported with vfio-pci backends - the error is kind of confusing on s390 because the definition doesn't even contain the attribute, because libvirt adds it by default, which is wrong with vfio-ccw