Dear Laurent,
Thank you for your quick reply. We used qemu-7.1, but it is reproducible
with qemu from v6.2 to the recent v8.0 release candidates.
I found that it's introduced by the commit 9323f892b39 (between v6.2.0-rc2
and v6.2.0-rc3).
If it doesn't break anything else, it suffices to remove the line below
from acpi_pcihp_device_unplug_request_cb():
pdev->qdev.pending_deleted_event = true;
but you may have a reason to keep it. First of all, I'll open a bug in the
bug tracker and let you know.
Best regards,
Yu Zhang
On Mon, Apr 3, 2023 at 6:32 PM Laurent Vivier <[email protected]> wrote:
> Hi Yu,
>
> please open a bug in the bug tracker:
>
> https://gitlab.com/qemu/qemu/-/issues
>
> It's easier to track the problem.
>
> What is the version of QEMU you are using?
> Could you provide QEMU command line?
>
> Thanks,
> Laurent
>
>
> On 4/3/23 15:24, Yu Zhang wrote:
> > Dear Laurent,
> >
> > recently we run into an issue with the following error:
> >
> > command '{ "execute": "device_del", "arguments": { "id": "virtio-diskX"
> } }' for VM "id"
> > failed ({ "return": {"class": "GenericError", "desc": "Device
> virtio-diskX is already in
> > the process of unplug"} }).
> >
> > The issue is reproducible. With a few seconds delay before hot-unplug,
> hot-unplug just
> > works fine.
> >
> > After a few digging, we found that the commit 9323f892b39 may incur the
> issue.
> > ------------------
> > failover: fix unplug pending detection
> >
> > Failover needs to detect the end of the PCI unplug to start
> migration
> > after the VFIO card has been unplugged.
> >
> > To do that, a flag is set in pcie_cap_slot_unplug_request_cb() and
> reset in
> > pcie_unplug_device().
> >
> > But since
> > 17858a169508 ("hw/acpi/ich9: Set ACPI PCI hot-plug as default
> on Q35")
> > we have switched to ACPI unplug and these functions are not called
> anymore
> > and the flag not set. So failover migration is not able to detect
> if card
> > is really unplugged and acts as it's done as soon as it's started.
> So it
> > doesn't wait the end of the unplug to start the migration. We don't
> see any
> > problem when we test that because ACPI unplug is faster than PCIe
> native
> > hotplug and when the migration really starts the unplug operation is
> > already done.
> >
> > See c000a9bd06ea ("pci: mark device having guest unplug request
> pending")
> > a99c4da9fc2a ("pci: mark devices partially unplugged")
> >
> > Signed-off-by: Laurent Vivier <[email protected] <mailto:
> [email protected]>>
> > Reviewed-by: Ani Sinha <[email protected] <mailto:[email protected]>>
> > Message-Id: <[email protected]
> > <mailto:[email protected]>>
> > Reviewed-by: Michael S. Tsirkin <[email protected] <mailto:
> [email protected]>>
> > Signed-off-by: Michael S. Tsirkin <[email protected] <mailto:
> [email protected]>>
> > ------------------
> > The purpose is for detecting the end of the PCI device hot-unplug.
> However, we feel the
> > error confusing. How is it possible that a disk "is already in the
> process of unplug"
> > during the first hot-unplug attempt? So far as I know, the issue was
> also encountered by
> > libvirt, but they simply ignored it:
> >
> > https://bugzilla.redhat.com/show_bug.cgi?id=1878659
> > <https://bugzilla.redhat.com/show_bug.cgi?id=1878659>
> >
> > Hence, a question is: should we have the line below in
> acpi_pcihp_device_unplug_request_cb()?
> >
> > pdev->qdev.pending_deleted_event = true;
> >
> > It would be great if you as the author could give us a few hints.
> >
> > Thank you very much for your reply!
> >
> > Sincerely,
> >
> > Yu Zhang @ Compute Platform IONOS
> > 03.04.2013
>
>
