Commit Graph

3 Commits

Author SHA1 Message Date
Peter Krempa
1a691fe1c8 qemu: capabilities: Re-enable JSON syntax for -device
Now that qemu fixed device unplug when JSON syntax is used with -device
we can re-enable the feature.

Since the old capability string representation is condemned by
suggesting filtering it as a workaround we must introduce a new string.
To achieve this the original capability position is renamed to
X_QEMU_CAPS_DEVICE_JSON_BROKEN_HOTPLUG and a new position with the
original name QEMU_CAPS_DEVICE_JSON is introduced to prevent us having
to change the rest of the code.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-01-17 09:26:17 +01:00
Peter Krempa
bd3d00babc qemu: Revert to using non-JSON commandline for -device
When -device is configured via JSON a bug [1] is triggered in qemu were
the DEVICE_DELETED event for the removal of the device frontend is no
longer delivered to libvirt. Without the DEVICE_DELETED event we don't
remove the corresponding entries in the VM XML.

Until qemu will be fixed we must stop using the JSON syntax for -device.

This patch removes the detection of the capability. The capability is
used only during startup of a fresh VM so we don't need to consider any
compaitibility steps for existing VMs.

For users who wish to use 'libvirt-7.9' and 'libvirt-7.10' with
'qemu-6.2' there are two possible workarounds:

 - filter out the 'device.json' qemu capability '/etc/libvirt/qemu.conf':

   capability_filters = [ "device.json" ]

 - filter out the 'device.json' qemu capability via qemu namespace XML:

   <domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
     [...]
     <qemu:capabilities>
       <qemu:del capability='device.json'/>
     </qemu:capabilities>
   </domain>

We must never again use the same capability name as we are now
instructing users to filter it as a workaround so once qemu is fixed
we'll need to pick a new capability value for it.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2036669

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2035237
Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ani Sinha <ani@anisinha.ca>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2022-01-10 09:35:00 +01:00
Michal Privoznik
58bf03f85e qemu: Generate command line for tb-cache feature
Generating command line is pretty easy - just put tb-size=XXX
onto -accel tcg part. Note, that QEMU expects the size in MiB.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/229
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Tested-by: Kashyap Chamarthy <kchamart@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
2021-12-13 17:10:03 +01:00