Hi Peter, Thank you for pointing that out, I will track the issue on that bug instead.
Yalan On Thu, Sep 8, 2022 at 3:58 PM Peter Krempa <pkre...@redhat.com> wrote: > On Thu, Sep 08, 2022 at 15:16:56 +0800, Yalan Zhang wrote: > > Hi Laine, > > > > As for the hot-unplug behavior, I have one more question about it, could > > you please help to confirm? > > > > unplugging a PCI device properly requires cooperation from the guest OS. > > > If the guest OS isn't running yet, the unplug won't complete, so qemu > > > (and libvirt) still show the device as plugged into the guest. > > > > > > virsh reports success on the unplug because unplugging a device is done > > > asynchronously - the "success" means "libvirt successfully told qemu to > > > unplug the device, qemu has told the virtual machine to unplug the > > > device, and is waiting for acknowledgment from the virtual machine that > > > the guest has completed removal". At some later time the guest OS may > > > complete its part of the unplug; when that happens, qemu will get a > > > notification and will send an event to libvirt - at that time the > device > > > will be removed from libvirt's list of devices. > > > > > > tl;dr - this is all expected. > > > > > > > The question is that, when I unplug it during boot, the virsh cmd will > > succeed but the interface still exists, which is expected. > > After the vm boot successfully, the guest OS will *not* complete this > > removal. When I tried to detach it again, it reported that the device was > > in the process of unplugging. > > Is this acceptable? > > > > # virsh detach-interface rhel_new network 52:54:00:36:a8:d4 > > Interface detached successfully > > # virsh domiflist rhel_new > > Interface Type Source Model MAC > > ------------------------------------------------------------- > > vnet4 network default virtio 52:54:00:36:a8:d4 > > > > # virsh detach-interface rhel_new network 52:54:00:36:a8:d4 > > error: Failed to detach interface > > error: internal error: unable to execute QEMU command 'device_del': > Device > > net0 is already in the process of unplug > > The same problem was already reported for disks: > > https://bugzilla.redhat.com/show_bug.cgi?id=2087047 > > https://gitlab.com/libvirt/libvirt/-/issues/309 > > The main problem is that qemu doesn't re-send the request to unplug the > device and rather reprots an eroror. At the same time the guest OS > doesn't notice it any more, so the unplug can't be finished until the VM > is rebooted. > >
