On 2025-06-10 12:29, Trupti wrote:
On 2025-06-09 23:38, Andrea Bolognani wrote:
On Mon, Jun 09, 2025 at 09:50:24AM +0530, Trupti wrote:
Package: libvirt-daemon
Severity: important
Tags: trixie ppc64el
Version Info:
Host/Guest OS: Debian Trixie/sid (powerpc64le)
Kernel: 6.12.27-powerpc64le-64k
QEMU: 10.0.0
Libvirt: 11.3.0
Issue:
Live-attaching or detaching a device with virsh on a Debian Trixie
(ppc64le)
guest does not take effect immediately. While the host command
succeeds, the
guest OS only recognizes the change after a full reboot. This defeats
the
purpose of the hotplug feature.
Steps to reproduce:
1) Start a guest with Debian-Trixie OS same as Host
2) Attach an interface to guest using below virsh attach-device
command
'virsh attach-interface --live vm bridge --source virbr0'
3) The command executes successfully and give output as "Interface
attached
successfully"
4) But the interface is not immediately attached to guest. When the
guest is
rebooted , then the
interface is seen on the guest.
5) Same is happening with virsh detach-interface command. A guest
reboot is
required to remove
the interface from guest
What's the output of attach-interface if you pass the --print-xml
flag to it? What does the full live XML look like before and after
the operation?
I have gathered the diagnostic information you requested.
virsh attach-interface --live vm bridge --source virbr0 --print-xml
The command produced the following output:
<interface type='bridge'>
<source bridge='virbr0'/>
</interface>
I have attached the two files, before.xml and after.xml.
Honestly this sounds like a guest OS issue rather than a bug in
libvirt. Is any message produced in dmesg/journal as a consequence of
the hotplug operation?
The guest dmesg shows the RTAS hot-plug signal, but no further messages
appear.
Thanks Trupti
Hello,
I have a key update from further testing.
Libvirt appears to be working correctly, as the VM's live XML is updated
immediately after an attach-interface command.
The main finding comes from the guest kernel log. It reveals that both
attach-interface and detach-interface cause the guest to receive the
exact same signal: RTAS Hotplug Event (229).
Receiving the same signal for both adding and removing a device is the
probable cause of the hotplug failure.
Thanks Trupti.
