Re: [PATCH v6 3/6] failover: fix unplug pending detection

[Laurent Vivier]

On 07/12/2021 05:13, Ani Sinha wrote:
> On Mon, 6 Dec 2021, Laurent Vivier wrote:
>
> > 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")
>
> This has already been merged upstream:
> https://git.qemu.org/?p=qemu.git;a=commit;h=9323f892b39d133eb69b301484bf7b2f3f49737d

Sorry, I forgot to rebase my series before sending.

Thank you for the remark.

Laurent