From: "Daniel P. Berrangé" <berrange@redhat.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>,
Juan Quintela <quintela@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel@nongnu.org, Ani Sinha <ani@anisinha.ca>,
Igor Mammedov <imammedo@redhat.com>,
Jens Freimann <jfreimann@redhat.com>
Subject: Re: [PATCH v3] failover: fix unplug pending detection
Date: Fri, 1 Oct 2021 11:48:55 +0100 [thread overview]
Message-ID: <YVbnl7hcvNLMYj/e@redhat.com> (raw)
In-Reply-To: <20211001104514.46bhlpenx4rz2qnm@sirius.home.kraxel.org>
On Fri, Oct 01, 2021 at 12:45:14PM +0200, Gerd Hoffmann wrote:
> On Fri, Oct 01, 2021 at 10:25:02AM +0200, 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().
>
> > + /*
> > + * pending_deleted_event is used by virtio-net failover to detect the
> > + * end of the unplug operation, the flag is set to false in
> > + * acpi_pcihp_eject_slot() when the operation is completed.
> > + */
> > + pdev->qdev.pending_deleted_event = true;
>
> This has the side effect of blocking a second 'device_del' command.
>
> So, in case the first time didn't work (for example due to the guest not
> listening because grub just doesn't do that), you can try a second time
> once the linux kernel is up'n'running.
>
> I suspect this patch will break that (didn't actually test though).
That's important because OpenStack will definitely trigger
multiple device_del commands in a row if they don't get a
success from an initial one.
Regards,
Daniel
--
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next prev parent reply other threads:[~2021-10-01 10:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-01 8:25 [PATCH v3] failover: fix unplug pending detection Laurent Vivier
2021-10-01 10:45 ` Gerd Hoffmann
2021-10-01 10:48 ` Daniel P. Berrangé [this message]
2021-10-01 11:01 ` Laurent Vivier
2021-10-01 12:49 ` Gerd Hoffmann
2021-10-01 13:17 ` Ani Sinha
2021-10-01 15:19 ` Ani Sinha
2021-10-05 15:14 ` Michael S. Tsirkin
2021-10-05 16:01 ` Laurent Vivier
2021-10-06 5:53 ` Ani Sinha
2021-10-18 7:19 ` Laurent Vivier
2021-10-18 8:27 ` Michael S. Tsirkin
2021-11-18 9:15 ` Laurent Vivier
2021-11-18 10:04 ` Ani Sinha
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